Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University Table of Contents 1 INTRODUCTION ..............................................................................................................................................1 2 RESEARCH OBJECTIVES ..............................................................................................................................5 3 LITERATURE REVIEW ..................................................................................................................................6 3.1 INTRODUCTION ..............................................................................................................................................6 3.2 TREATMENT OF MULTICOMPONENT DIFFUSION PROCESSES ..........................................................................6 3.2.1 Single Phase ..........................................................................................................................................6 3.2.2 Multiphase.............................................................................................................................................7 3.3 Thermodynamics of Ni-Cr-Al system........................................................................................................8 3.4 COATING LIFE PREDICTION ............................................................................................................................8 3.4.1 C.E. Campbell .......................................................................................................................................8 3.4.2 J.E. Morral ............................................................................................................................................9 3.4.3 M.A. Dayananda .................................................................................................................................10 3.4.4 J.A. Nesbitt ..........................................................................................................................................12 4 APPROACH USED ..........................................................................................................................................13 4.1 SEM/EDA ANALYSIS ..................................................................................................................................14 4.2 IMSL PROGRAM...........................................................................................................................................16 4.3 REPRODUCTION OF THERMODYNAMIC DIAGRAMS ........................................................................................18 4.4 MODIFICATION OF COSIM CODE .................................................................................................................19 5 RESULTS ..........................................................................................................................................................20 5.1 SEM/EDA ANALYSIS ..................................................................................................................................20 5.2 IMSL PROGRAM...........................................................................................................................................24 5.2.1 Input and Output .................................................................................................................................24 5.2.2 Diffusion Treatment.............................................................................................................................24 5.2.3 Initial Approximation ..........................................................................................................................25 5.2.4 Calculated profiles ..............................................................................................................................25 5.3 REPRODUCTION OF THERMODYNAMIC DIAGRAMS ........................................................................................28 6 DISCUSSION....................................................................................................................................................32 7 CONCLUSIONS ...............................................................................................................................................35 8 REFERENCES .................................................................................................................................................37 9 APPENDICES...................................................................................................................................................39 9.1 TABLES ........................................................................................................................................................39 9.2 SELECTED MICROGRAPHS ............................................................................................................................40 9.3 CONCENTRATION PROFILES .........................................................................................................................41 9.4 IMSL PROGRAM INPUT FILE .........................................................................................................................47 9.5 THERMO-CALC TDB FILE ............................................................................................................................50 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 1 Introduction The gas turbine was not always at the forefront of aerospace propulsion, nor was it a factor in power generation. In 1940, a committee put together by the National Academy of Sciences to evaluate possibilities of gas turbines came to the following conclusion, “In its present state, and even considering the improvements possible when adopting the higher temperatures proposed for the immediate future, the gas turbine engine could hardly be considered a feasible application to airplanes mainly because of the difficulty in complying with the stringent weight requirements imposed by aeronautics.”1 Despite the committee’s educated recommendation, Frank Whittle proceeded with his research into gas turbines, and on April 8, 1941, the first flight of the British jet fighter Gloster E28 powered by a Whittle W-1 jet engine marked the beginning of this remarkable technology. Industrial gas turbines and jet aircraft engines have only one moving part, the common shaft which has compressor blades and turbine blades, otherwise known as the hot section because of the temperatures at which it operates. In order for these devices to have greater efficiency and output/thrust, the temperature at which the combustion gas enters the hot section must be as high as possible (Figure 1, Figure 2) 1 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University Figure 1 Output as a function of turbine inlet temperature2 Figure 2 Efficiency as a function of inlet temperature2 A class of materials with corrosion/oxidation resistance and excellent mechanical properties at high temperatures (creep, fatigue resistance), known as superalloys were developed to be used in gas turbines. Today, the most common superalloys are Ni- and Co-based, consisting of an FCC matrix (γ) with precipitates of FCC Ni3(Al,Ti) (γ') as seen in Figure 3. γ′ γ Figure 3 SEM micrograph of GTD-111 microstructure after 9000hrs. @ 940°C (2500x) Other alloying elements include C, Cr, Mo, W, Ta, Zr, B, Re, Y, Nb all for the purpose of enhancing high temperature longevity in one way or another. During high temperature service, these alloy systems develop at protective oxide layer (mainly Al2O3) on the exposed 2 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University surface which acts a protective barrier against further oxidation. The prolonged use of these devices creates a requirement for greater protection. The solution has been to coat the components exposed to the harshest environments (hot section) with an Al-rich coating of similar structure to the base alloy. These MCrAlY (M=Ni and/or Co) coatings consist again of an FCC matrix (γ), with BCC NiAl (β) precipitates (Figure 4). These particles act as sources of Al for oxidation and the coating continues to oxidize sacrificially to protect the expensive base alloy. In this way, the coatings are consumable, and at prescribed times are stripped and replaced. Another consequence of high temperature service is the interdiffusion of elements between coating and base alloy to eliminate gradients in chemical potential. β γ Figure 4 Photomicrograph of GT-33 (NiCoCrAlY) coating microstructure after 343hrs. @ 1050°C (40x) The art which requires science is in coating life prediction. The most common analysis tool is to use an empirical relationship for β depletion in the coating. The simplicity of this measurement and the independence from first principles calculations make it attractive to some, but make it difficult to use in different situations if diffusion in different phases dominates the process at different temperatures. 3 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University It would be valuable to have an accurate model of coating degradation, capable of predicting the effects of interdiffusion. This would enable users to run their machines, typically costing between $10M and $30M to run to their fullest extent without the risk of catastrophic oxidation of the blade alloys which cost anywhere from $500,000 to $3M per row to replace. Area of interest containing multiple rows of blades Figure 5 Gas turbine schematic 4 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 2 Research Objectives • To model diffusion in the whole superalloy-coating system for a Ni-based superalloy with MCrAlY overlay coating by back calculating diffusion parameters from concentration profiles • To develop thermodynamic database for Ni-Cr-Al system for generating relevant phase diagrams and for calculating the thermodynamic properties needed 5 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 3 Literature Review 3.1 Introduction In order to determine how MCrAlY coatings degrade with time, both the thermodynamics and the kinetics of the system must be known. It this can be done, an accurate description of the system can be established and the dynamics of the operation of these devices can be understood. 3.2 Treatment of Multicomponent Diffusion Processes 3.2.1 Single Phase Onsager’s formalism of Fick’s laws for a multicomponent diffusion is described with (n-1)2 interdiffusion coefficients for an n-component system, and the flux of species i is expressed by n −1 ~ ∂C j J i = −∑ Dij ∂z j =1 (1) ~ where D is the matrix of interdiffusion coefficients [(n-1) x (n-1)]. For example, in the quaternary case, the flux of component i would be expressed as ~ ∂C ~ ∂C 2 ~ ∂C 3 J i = − Di1 1 − Di 2 − Di 3 ∂z ∂z ∂z (2) In this case, the interdiffusion matrix would contain nine parameters, which in the general case, may be concentration dependent. To evaluate these terms base on previous methods, two diffusion couples must be prepared with a common composition in the diffusion zone where the interdiffusion coefficients are to be evaluated3,4. 6 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University If it can be assumed that the elements of the diffusion matrix are constant with respect to compositions, analytical solutions for isothermal systems are well established5-9, but if this assumption is not valid, numerical methods must be employed. 3.2.2 Multiphase Diffusion in multiphase systems is much more common and adds great complexity to the problem. Second phase particles have been known to increase or decrease diffusivity of the overall system depending on their magnitudes with respect to the matrix10. Along with being sources or sinks of solute atoms, the fraction of these phases can also change during diffusion processes to accommodate changing concentrations. Moreover, as demonstrated by Hopfe and Morral11, diffusion paths in two phase regions of a multicomponent system have discontinuities and are typically composed of straight lines, and can be ‘serpentine’ or ‘zigzag’ between subsequent regions. This is caused by the fact that the inequality ∂µ i > 0 is not ∂C i automatically held in mulcicomponent systems.. The calculation of effective mass transport properties for multiphase systems can be incredibly complex, making the use of approximations very common. One such approximation involves multiplying the diffusivities of alloying elements in the matrix by a so-called labyrinth factor10. Engstrom et al simulated the diffusion paths of several single phase and multiphase superalloy couples. This was conducted assuming diffusion occurred entirely within the matrix phase, and during each step in the simulation the volume fraction and composition of the precipitates remained constant. 7 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University They simulated γ/γ+β, γ+β/γ+β and γ+β/γ+β+γ' and single phase diffusion couples simply containing Ni, Cr and Al which showed, for example, how a γ/γ couple can exhibit the behavior of forming γ' at the interface. 3.3 Thermodynamics of Ni-Cr-Al system Thermodynamic databases usually constructed via the thermodynamic optimization (i.e. CALPHAD12) method allow constructing a wide variety of phase diagram and property diagrams. Huang and Chang13 published the thermodynamic description of the Ni-Cr-Al system, which was re-worked into a corresponding THERMO-CALC14 compatible database. In this work, they modeled the liquid(L), FCC(γ), BCC(α), and two ordered phases (γ' and β). γ, L, and α are treated as substitutional solutions, while γ’ and β utilize several sublattices. Binary compounds existing in the Ni-Cr-Al system were also included. 3.4 Coating Life Prediction A coating is considered spent when it no longer serves its function; that is to produce a stable, protective oxide. Since the protective oxide is Al2O3, a critical concentration of Al (usually around 1wt%) is a logical choice for determining coating life. By calculating the time when this level is reached, expensive shut downs for evaluation of components, and even more expensive repairs can be reduced or ideally avoided. Most studies are conducted on either interdiffusion or oxidation, but since the focus of this work is interdiffusion, this is where the most time will be spent. 3.4.1 C.E. Campbell Using diffusion couples of René-88/Ni, and René-88/Inconel 718 whose composition are found in the appendix, Campbell et al15 compared the diffusion couples which were observed 8 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University using a CAMECA (Paris, France) microprobe with those calculated using DICTRA16 software. In order to generate accurate concentration profiles with DICTRA16, the Ni-Data thermodynamic database17 was utilized in conjunction with the diffusion mobility data based by Campbell et al18 to re-calculate the equilibrium using THERMO-CALC14 at each time step. This fundamental study of diffusion processes in superalloys used samples aged for 1000 hours at 1150°C followed by a water quench to produce a single phase structure. By using these samples, the intricacies of multi-phase diffusion were avoided, but validation of the mobility database18 was successful. 3.4.2 J.E. Morral J.E. Morral has been involved with numerous studies into diffusion behaviour of Ni-Cr-Al alloys. One such study investigated three types of boundaries found in Ni-Cr-Al diffusion couples19 using the difference in equilibrium phases on either side of the interface to distinguish between them (i.e. γ/γ+β Î 2-1 Î type 1). In 1994, Morral et al.20 used a piece of software called “Profiler” to generate concentration profile of Al and Cr in several γ+β (NiCr-Al) diffusion couples. This work represented the first diffusion analysis conducted on a pair of two phase alloys, rather than a single phase coupled to a two phase, and this generated the first diffusion paths on this style of diffusion couple. Later, a similar study was conducted using DICTRA16 software. It was assumed that diffusion only occurred in the matrix phase, and the precipitates only act as sources or sinks. During each time step, only the composition of the matrix changed, while the composition and volume fraction of the precipitates 9 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University remained constant. Again, Morral et al. used these simulations to show the “zig-zag” diffusion path demonstrated earlier by Hopfe and Morral11. 3.4.3 M.A. Dayananda If it is assumed that the diffusion coefficients are independent of concentration or if the concentration dependence is insignificant; an isothermal diffusion couple with minimal changes in concentration can be assumed to have constant diffusion coefficients. It is based on these assumptions that Dayananda explored average effective diffusion coefficients21-24 to calculate ternary diffusion profiles. The analysis is based on the Botzmann-Matano method25 which yields the relation for diffusion coefficients as a function of composition C′ D (C ' ) = − 1 ⎛ dz ⎞ ⎤ ⎟ ⋅ (z − Z M )dC ⎜ 2t ⎝ dC ⎠⎥⎦ C ′ C∫R (3) where t ≡ time, z ≡ position, ZM ≡ position of Matano interface, C ≡ concentration, CR ≡ concentration at left most point and C' ≡ concentration of interest. From equation 3, the flux can be expressed as dCi 1 C ' J i = − D (C ' ) = ( z − Z m )dCi dz 2t C∫R (4) which can be equated to the ternary flux equation (2) ~ ∂C ~ ∂C J i = − Di31 1 − Di32 2 ∂z ∂z (5) Integrating the latter equation with respect to z yields, 10 Tuesday, September 06, 2005 Richard Meguerian z2 C1 ( z 2 ) ∫ J dz = − ∫ C2 ( z2 ) ∫ 3 i1 i z1 D dC1 − TMS Outstanding Student Paper Contest 2005 McMaster University C1 ( z1 ) Di32 dC 2 → J i ( z 2 − z1 ) = D i1 [C1 ( z1 ) − C1 ( z 2 )] + D i 2 [C 2 ( z1 ) − C 2 ( z 2 )] 3 3 (6) C2 ( z1 ) This gives two equations (species 1 and 2) for the determination of four variables (diffusion coefficients). The other two equations come from a modified version of Fick’s law based on 3 the assumption that the effective diffusion coefficients D ij are constant over the selected composition range. 3 J i = − D i1 3 ∂C ∂C1 − Di2 2 ∂z ∂z (7) If equation 7 is multiplied by (z - z0)n and integrated over the diffusion zone, z2 ∫ J (z − z i z1 0 )dz = − D 3 i1 C1 ( z 2 ) ∫ (x − x ) 0 C1 ( z 2 ) n dC1 − D 3 i2 C2 ( z 2 ) ∫ (x − x ) 0 n dC 2 (8) C2 ( z 2 ) When n=0, we obtain the previous set of two equations, but if n=1, unique equations are obtained and complete the system of equations, containing only easily calculated values available from the concentration profiles. After calculation of the average effective diffusion coefficient on both sides of the Matano interface, the average is taken and reported. Dayananda has released a piece of software, MultiDiFlux which reads ternary concentration profile to back calculate the effective interdiffusion coefficients over specific composition ranges based on the method presented here. 11 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 3.4.4 J.A. Nesbitt Coupling both oxidation and interdiffusion in overlay-coated turbine parts, Dr. Nesbitt’s work26 allows the specification of oxidation, spallation and interdiffusion parameters along with dimensions of the system in order to calculate ternary concentration profiles (Figure 6). His software, entitled COSIM (Coating Oxidation and Substrate Interdiffusion Model), was developed in the mid 1980s at NASA, but the source code was recently made available publicly. Figure 6 Sample COSIM output for a 250µm coating at 850°C (Coating: Ni-40Cr-9Cr, Alloy: Ni-20Cr4Al) 12 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 4 Approach Used The calculation of accurate diffusion data is tedious, and requires many experiments. Based on Onsager’s formalism, quaternary diffusion is expressed with three equations and nine diffusion coefficients. If it can be assumed that local equilibrium is maintained in the direction parallel to the coating/substrate interface, then all diffusion takes place in the direction normal this interface and the problem can be made one dimensional. This is valid since the only diffusion parallel to the interface is due to the growth of the γ’ phase in the matrix which can be considered slow with respect to the diffusion of atoms across the coating/substrate interface. Moreover, if the partial molar volumes of each phase are assumed to be equal15,18, then the average composition within a control volume can be used instead of the matrix and/or precipitates. Following this logic, mass transfer will be modeled using a set of “operative” diffusion coefficients rather than phase-specific ones assuming that a representative sample is taken for concentration measurements and that a reasonable averaging procedure is used. Although these values will be different from the classical interdiffusion coefficients, they still relate mass transport to fluxes and will therefore be useful in modeling processes between the coating and substrate. Fick’s second law can now be expressed as, ∂Ci ∂ 2 C1 ˆ ∂ 2 C 2 ˆ ∂ 2 C3 = Dˆ i1 + Di 2 + Di 3 ∂t ∂z 2 ∂z 2 ∂z 2 (9) where D̂ij are the operative diffusion coefficients and Ci represents the volume average concentration of component i. 13 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University By collecting concentration profiles from available diffusion couples (Table 1), an optimization can be carried out to calculate the operative diffusion coefficients. Table 1 Samples available for diffusion analysis NiCoCrAlY/Ni-base Coating: GT-33 Alloy: DS GTD-111 Couple Mount No. 35C 1691 35E 2287 35F 3188 35H 1485 35I 1682 35J 1897 35N 1444 35O 1462 35P 1533 35Q 1643 35T 1423 35U 1453 35V 1524 CoCrAlY/Ni-base Diffusion Diffusion Coating: GT-29 Temperature, time, Alloy: GTD-111 °C(°F) (hrs.) Couple Mount No. 58C 1698 865 (1589) 1959 58E 2294 865 (1589) 8698 58F 3195 865 (1589) 17054 58H 1492 940 (1724) 492 58I 1689 940 (1724) 1980 58J 1904 940 (1724) 4512 58N 1451 990 (1814) 119 58O 1469 990 (1814) 324 58P 1540 990 (1814) 711 58Q 1650 990 (1814) 1338 58T 1430 1050 (1922) 187 58U 1460 1050 (1922) 343 58V 1531 1050 (1922) 736 4.1 SEM/EDA Analysis The process of collecting concentration profiles was conducted on a Philips 515/Link EDA scanning electron microscope (SEM) with LaB6 filament. The accelerating voltage was 20keV, and the filament current was set to 15µA. In order to acquire accurate concentration profiles, a method was developed to take the volume average composition at individual points along the direction of interest. By setting the electron gun to scan a line perpendicular to the diffusion trajectory, rather than focusing on a point while collecting an x-ray spectrum, the average over a volume equal to the length of the scan (~500µm) by the interaction volume width (~1µm) and by the interaction volume depth (~1µm) can be accurately acquired (Figure 7). 14 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University Alloy Z1 Z2 Coating Z3 Z4 Z5 Z6 Z7 Z8 Figure 7 Use of scan feature to collect average concentration profiles (green) for main trajectory (red) over different position (z) values. The length of the scan can be justified since the microstuctural features (γ′ precipitates) in the alloy are on the order of 500nm and in the coating, β phase is essentially continuous. Therefore, any scan length in the order of hundreds of microns is a representative sample. Although the coating/alloy interface is easy to see on an etched sample (Figure 7), in order to get optimal X-ray emission and measurement, the surface must be smooth to approximately 1µm. Therefore, using an etched sample is not practical. As seen in Figure 8, the original interface can be observed by the increased porosity due to the alloy being grit blasted before the application of the coating. 15 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University Original interface Figure 8 SEM micrograph showing original coating/alloy interface by porosity from grit blasting (550x ) In order to ensure that accurate concentration profiles could be extracted from the X-ray spectrums, a superalloy was solution treated to produce a single phase structure, and then sent to an independent lab where turnings were analyzed for composition. These samples were then used to standardize the SEM software (URSA 1.3). This ensures that the “matrix effects” are taken into account rather than just pure elements standards generally used. 4.2 IMSL program Once the concentration profiles have been obtained, an analysis was conducted to calculate the operative diffusion coefficients. To carry out these calculations, a Fortran 90 compiler 16 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University was used with the IMSL Fortran Library by Visual Numerics27. Within this library, there exists MOLCH, a robust subroutine which can be utilized to solve a system of partial differential equations. This allows the calculation of concentration profiles at different times and temperatures starting from specified initial conditions and operative diffusion coefficients by solving the modified version of Fick’s second law for a substitutional solution. ∂C1 ∂ 2 C1 ˆ ∂ 2 C 2 ˆ ∂ 2 C 3 ˆ = D11 + D12 + D13 ∂t ∂z 2 ∂z 2 ∂z 2 (10) ∂C 2 ∂ 2 C1 ˆ ∂ 2 C 2 ˆ ∂ 2 C 3 ˆ = D21 + D22 + D23 ∂t ∂z 2 ∂z 2 ∂z 2 (11) ∂C3 ∂ 2 C1 ˆ ∂ 2 C 2 ˆ ∂ 2 C3 = Dˆ 31 + D32 + D33 ∂t ∂z 2 ∂z 2 ∂z 2 (12) ∂C 4 ∂ = − (C1 + C 2 + C 3 ) ∂t ∂t (13) This is conducted with zero-flux boundary conditions. After profiles are calculated at the times and temperatures of the corresponding specimens, an analysis is conducted to determine how close the calculations are to the experimental counterparts. This comparison is conducted with a non-linear least squares analysis in conjunctions with another IMSL function (UNLSF) where appropriate changes are made to the operative diffusion matrix to reduce the sum of the squares of the operative function (Equation 14). calc exp ⎛ C kji ( z kji ) − C kji ( z kji , Dˆ ) ⎞ ⎜ ⎟ ∑∑∑ exp ⎜ ⎟ C ( z ) ∆ i =1 j =1 k =1 kji kji ⎝ ⎠ N N i M ij 2 (14) where N is the number of components, Ni is the number of profiles for component i, and Mi j is a number of spatial points for j-th profile of the i-th component. 17 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University The minimization continues until the stopping criterion is met. UNLSF utilizes the Levenberg-Marquardt algorithm28 to evaluate the non-linear terms. Is the stopping criterion satisfied? Change D matrix Initial approximation of the D matrix (diagonal, etc.) Solve system of PDEs (modified Fick’s 2nd law) for conc. profiles from initial profiles Determine the direction which D components are to be changed Compare results with experimental counterparts Figure 9 Iteration process for determining operative diffusion coefficients 4.3 Reproduction of thermodynamic diagrams Phase diagrams can be generated based on published thermodynamic properties13 and Thermo-Calc software package14. These properties were entered as a database of excess Gibbs energy functions with standard states from a well-sourced reference by Dinsdale29. The phases included in the analysis were: γ, γ', σ, β, L, α; and compounds: Al11Cr2, Al13Cr2, Al3Ni, Al3Ni2, Al3Ni5, Al4Cr, Al8Cr5, Al9Cr4 and AlCr2. A thermodynamic description of the Co-Cr-Al system is not readily available in literature like the Ni-Cr-Al system, but is available for purchase17. This limited the evaluation to only Ni, Cr and Al. 18 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 4.4 Modification of COSIM code Due to the fact that the COSIM code is publicly available, it is possible, time permitting, to modify the program to use operative diffusion coefficients. Following appropriate modifications, it will simulate a gas turbine blade in service under a variety of conditions. Using the determined operative diffusion coefficients, estimates of oxidation/spallation parameters and the appropriate dimensions, coating lifetime can be estimated based on a critical aluminum concentration in the coating. 19 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 5 Results 5.1 SEM/EDA Analysis The calibration of distances on the SEM, although normally not an issue, was paramount for this study, and had to be completed before the acquisition of concentration profiles. To ensure that the stage micrometers were accurate in the plane of interest, a transmission electron microscope (TEM) grid was attached to a representative sample with carbon tape and observed on the SEM. Knowing the certified spacing of the grid and moving the sample stage a specified distance using the stage micrometers, it was confirmed that the stage micrometers offer the degree of accuracy required for this study. Figure 10 SEM micrograph of grid used to calibrate the stage micrometers (13.2x) Figure 11 Higher magnification of Figure 10 showing details of grid (424x) This proved that as long as the surface being studied is parallel to the sample stage, and that the stage tilt remains constant (30°), the micrometers are accurate. If either one of these variables changes, the stage micrometers cannot be used. Controlling the stage tilt is a trivial task, but small variations in height across the samples results in different take off angles (TOA). 20 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University y θ e- x Sample Sample stage Figure 12 Effect of variation in height across sample Although each sample had a slightly different TOA, the maximum deviation of any sample was less than 10°. From Figure 12, it can be seen that y= x cos(θ ) (15) For and ideal case when θ = 0 D , y=x, but when θ = 10 D , y=1.015x, resulting in an error of only ±1.5% for the maximum deviation in TOA. The smallest spacing between spatial data points that was feasible using the stage micrometer was 10µm. If higher resolution was needed, the electron gun had to be repositioned and interpolation of distances from the monitor would be required. Since this was the case, most differential distances were multiples of 10µm. At these increments, the small amount of play in the stage micrometers becomes an issue. This is referred to as gear lash, and is unavoidable with mechanical systems. It cannot be eliminated, only reduced. This was accomplished by 21 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University proceeding in the same direction between points to keep continuous pressure on the same side of the gears. By doing this, the incremental change in position remains constant and accurate. The EDA spectrums for each line scan were collected until the X-ray count has reached 200 000. This allowed for ample averaging from all points on the line and ensures an adequate signal to noise (background) ratio. To get accurate compositions, all elements that were known to be in the material were labeled for quantitative analysis (Ni, Al, Cr, Co, Ti, W, Ta, Mo) in the EDA spectrum (Figure 13). Figure 13 EDA spectrum for sample 1485 at a position 90µm from the original interface into the alloy. The software was instructed to normalize results because all elements had been identified, and the standard which was created earlier with the single phase sample was implemented. A similar spectrum was acquired for each point on each sample, then quantitatively analyzed, recorded, and repeated. After all data about a single diffusion couple was organized, a concentration profile could be generated as seen in Figure 14. 22 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University Table 2 Truncated concentration data for diffusion couple 1462 80 Concentration (wt%) 70 60 50 Distance from interface Ni -150 -110 -90 -70 -50 -40 -30 -20 10 20 30 40 50 70 90 110 150 200 300 500 Certified Composition Position 8 7 6 5 4 3 2 1 9 10 11 12 13 14 15 16 17 18 19 20 Co 36.33 36.56 36.07 36.89 39.72 41.56 39.15 40.3 37.27 40.8 56.37 61.69 64.13 64.28 64.7 64.6 64.44 66.22 63.56 65.82 wt% Cr 33.36 33.93 33.79 32.78 30.89 29.43 30.84 29.63 32.57 29.81 20.94 12.36 10.18 9.13 9.86 9.8 10.31 9.43 10.44 9.54 Al 18.15 19.03 19.24 19.58 16.77 15.07 17.29 16.18 20.06 17.63 9.02 11.65 11.37 11.67 12.34 12.09 12.5 10.99 12.83 11.53 Coating 10.43 9.43 9.25 8.85 11.03 12.12 10.23 11.81 7.4 9.17 7.13 4.82 4.48 3.58 3.34 3.56 3.08 3.44 3.06 3.35 Sample: 1462 Spectrum File Name 1462008 1462007 1462006 1462005 1462004 1462003 1462002 1462001 1462009 1462010 1462011 1462012 1462013 1462014 1462015 1462016 1462017 1462018 1462019 1462020 Alloy Ni Co Cr Al 40 30 20 10 0 -200 -100 0 100 200 300 Distance from original interface (µm) Figure 14 Concentration profile for sample 1462 23 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University Despite the excellent correspondence with certified values as seen in Figure 14, this was not always the case. From other concentration profiles found in the appendix, Al and Cr measurements show great deviation from expected values. 5.2 IMSL program 5.2.1 Input and Output Upon running the executable, the user is prompted to enter the name of the input and output files that the software will interface with. As seen in section “9.4 IMSL program input file”, the format is simple and obvious. Any number of profiles with different times, temperature and spatial coordinates are automatically read from this file. Along with this, the number of components and identities of them are also read from the input file. This allows any number of components to be analyzed. After the optimization is complete, the software automatically outputs separate files for each component, time and temperature found in the input file. Within each file is the original data points (concentrations), experimental error, and calculated profiles for that time and temperature. The files are named appropriately with species, temperature and time (i.e. AlT990t1323.dat for Al @ 990°C, 1323hrs.) allowing quick checks to be performed on the correspondence between calculated and experimental profiles. 5.2.2 Diffusion Treatment Using the Arrhenius relation for diffusion coefficients, there are two variables to be taken into account. ⎛ E ⎞ D = Do exp⎜ − act ⎟ ⎝ RT ⎠ (16) 24 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University Do is the pre-exponential term and Eact is the activation energy. In the case of quaternary diffusion, there are nine Do and nine Eact terms. These terms are treated as independent of temperature and composition in this version of the software, but this could be changed in the future if a relationship was desired. The diffusion matrix must also be positive definite. Since MOLCH is unaware of the fact that it is calculating diffusion profile, a check that the matrix is positive definite is carried out each time a diffusion matrix is calculated. This is done by confirming that all eigenvalues are real and positive. If a matrix fails this test, it is disregarded and the optimization continues. 5.2.3 Initial Approximation Due to a great number of variables, it is possible that multiple minima of the objective function exist. To find an area in the minimization space to begin the optimization, an initial approximation of the solution is required. If the user does not have an approximation to supply the software, the computer generates random values within bounds specified for relevant terms and calculates the objective function (Equation 14). After a user-specified number of random terms have been generated and the objective function is calculated, the terms which produced the lowest value of the objective function is chosen as the starting point for the non-linear least squares optimization. 5.2.4 Calculated profiles As seen in Figure 15, the correspondence between calculated and experimental profiles for Co is quite good after a typical optimization. 25 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 40 35 Concentration (wt%) 30 Cexp Ccalc 25 20 15 10 5 -150 -100 -50 0 50 100 Distance from the original interface (µm) Figure 15 Calculated and experimental Co profile for sample 1691 Cr and Al showed larger deviations between experimental and calculated profiles. In most samples, the experimentally determined concentrations of Cr and Al were lower than the expected and calculated ones. 26 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 25 Concentration (wt%) Cexp Ccalc 20 15 10 -150 -100 -50 0 50 100 Distance from the original interface (µm) Figure 16 Calculated and experimental Cr profile for sample 1691 These results were typical of any optimization, although the exact values of diffusion parameters could be quite different from one time to the next. 27 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 10 Concentration (wt%) Cexp Ccalc 5 0 -150 -100 -50 0 50 100 Distance from the original interface (µm) Figure 17 Calculated and experimental Al profile for sample 1691 5.3 Reproduction of thermodynamic diagrams A database of thermodynamic properties of the Ni-Cr-Al system and the code produced can be seen in section “9.5 Thermo-Calc TDB File”. The following are reproductions of isothermal sections of the Ni-Cr-Al ternary phase diagram at temperatures corresponding to the samples studied. 28 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University γ γ+γ' β+ γ' γ' γ γ' α+ γ+ α+β γ' α+ β+ γ' α+ β α+ Figure 18 Ni-Cr-Al phase diagram at 865°C, with area of interest expanded γ γ+γ' ' β+ γ α+ γ' γ' α+ γ' γ' β+ α+β γ+ α+ β α+γ Figure 19 Ni-Cr-Al phase diagram at 940°C, with area of interest expanded 29 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University γ α+γ' γ+γ' β+ γ' γ' γ' γ' α+β β+ γ+ β α+ α+ α+γ Figure 20 Ni-Cr-Al phase diagram at 990°C, with area of interest expanded γ γ+γ' β+ γ' γ' α +β +γ β α+β ' β+γ α+β+γ α+γ Figure 21 Ni-Cr-Al phase diagram at 1050°C, with area of interest expanded It should be noted that the β+γ two-phase region is not stable except in the 1050°C samples. This explains why the formation of α and γ' can sometimes be observed at the alloy/coating 30 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University interface at lower temperatures. These diagrams must also not be taken as 100% accurate to the actual system since the interactions of other elements, specifically Co has not been taken into account, and it’s known that Co does not form all phases shown in the Ni-Cr-Al system. 31 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 6 Discussion The discrepancy between calculated and experimental Al profiles can be explained by the fact that the software uses the certified compositions of the coating and alloy as the concentration profiles for t=0 while the acquired profiles do not coincide with this. Mass is conserved during each time step because of the zero-flux boundaries imposed and expressed by Equation 17. ⎛ zn calculated ⎞ ⎛ zn ⎞ ⎜ C ⎟ ⎜ C ( z )dz ⎟ = ( z ) dz i i ⎜ z∫ ⎟ ⎜∫ ⎟ ⎝1 ⎠ ∀t >0 ⎝ z1 ⎠ t =0 (17) From the concentration profiles in the appendix, it is seen that there is significantly less Al in the system than should be seen since the coating is 10 wt% Al and the alloy is 3 wt% Al. Because of this, the computer cannot get an accurate match to the profiles. To prove that discrepancies between the actual and experimental concentration profiles are such a large source of error, the software was given the following initial conditions. Alloy: Al 1.4wt% Cr 12wt% Co 9.5wt% Ni BAL Coating: Al 6wt% Cr 17wt% Co 30wt% Ni BAL These values correspond with the concentrations from the endpoints of acquired profiles rather than the expected values. After the optimization was complete with these new initial values, the discrepancies were greatly reduced (Figure 22 and Figure 23) for all profiles and elements. This proved that the main source of the discrepancies for Al and Cr was the erroneous EDA acquired concentration profiles, and that the method was implemented correctly. 32 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University Concentration (wt%) 10 Cexp Ccalc 5 0 -150 -100 -50 0 50 100 Distance from the original interface (µm) Figure 22 Calculated and experimental Al profile for sample 1691 after initial conditions in optimization were changed Concentration (wt%) 25 Cexp Ccalc 20 15 10 -150 -100 -50 0 50 100 Distance from the original interface (µm) Figure 23 Calculated and experimental Cr profile for sample 1691 after initial conditions in optimization were changed 33 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University One explanation for the lower than expected Al and Cr concentrations may be the difficulty in standardizing elements using samples with less than 5 wt%. Since the SEM/EDA method was standardized using the same alloy which contains 4 wt% Al, calibration with a standard coating containing 10 wt% Al would hopefully allow already collected spectrums to be reanalyzed to acquire more accurate concentration profiles. Another aspect requiring attention is the fact that many solutions can be obtained from the same input file depending on the initial approximation. This is because the minimization space of 18 variables contains many local minima, and the quality of input data only adds to this problem. The only way to improve the chances of finding the best solution from the available data is to use a greater number of random approximations to increase the chances of finding the global minimum. If relationships were found between Eact or Do values in their respective matrices, then the number of variables could be reduced and possibly lead to a unique solution. Although many solutions can be obtained with greatly varying parameters, the calculated profiles remain very similar and the value of the objective function remains fairly constant for each optimization. 34 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 7 Conclusions This study has shown that it is possible to use the volume average composition of a superalloy/MCrAlY coating to model diffusion processes. This was conducted with GTD111 alloy and GT-33 NiCoCrAlY coating for numerous times and temperature. It has further proved that with accurate data, the method employed of non-linear least squares regression can accurately reproduce concentration profiles. The creation of a new standards file for evaluation of acquired spectrum may yield greatly improved correspondence between experimental and calculated profiles. If this is not successful, the Al and Cr data could be systematically modified to ensure that mass in conserved in the system. Consideration should be given to the possibility of using EPMA (Electron Probe Micro Analysis) on these samples to acquire more accurate concentration profiles if sufficient results cannot be obtained with current data. This will reduce scatter in the profiles, moreover, it could decrease the ambiguity of solutions by decreasing, if not eliminating the non-uniqueness of the solution. Although the non-uniqueness poses a problem when comparing the values of diffusion parameters with literature, if one is only interested in duplicating concentration profiles, and predicting profiles for different times and temperature, adequate results can be obtained immediately after addressing the problems with the Al and Cr profiles. Upon successful completion of current system, investigation should continue into other alloy/coating systems to determine the effects of composition on diffusion and create a coating life model for numerous alloys/coatings through the modification of the COSIM software with relevant oxidation/spallation parameters. 35 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University A Ni-Cr-Al thermodynamic database has been developed which can be made available on the McMaster University Materials Engineering Thermo-Calc server for use by all who use Thermo-Calc and available upon request. To follow up on this, the interactions associated with Co, although not currently available should be added when available to create a more accurate description of the actual system. 36 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 8 References 1. John Golley. Genesis of the Jet, Frank Whittle and the Invention of the Jet Engine, Airlife Publishing Ltd: 1996. 2. C.T.Sims; N.S.Stoloff; W.C.Hagel. Superalloys II, John Wiley & Sons, Inc.: 1987. 3. J.S.Kirkaldy. Canadian Journal of Physics 1958, 36, pp. 899-906. 4. J.S.Kirkaldy; D.J.Young. Diffusion in the Condensed State, The Institute of Metals, London: 1987. 5. W.Jost. Diffusion in Solids, Liquids, Gases, Academic Press, New York: 1952. 6. J.S.Kirkaldy. Advances in Materials Research. Herman, H. [4], 55. 1970. New York, Wiley. 7. P.K.Gupta and A.R.Cooper. Physica 54, 39. 1971. 8. M.S.Thompson and J.E.Morral. Acta Materialia 34, 339,2201. 1986. 9. F.J.J.van Loo, G.F.Bastin, and J.W.G.A.Vrolijk. Metallurgical and Materials Transactions A 18A, 801. 1987. 10. A.Engström; J.E.Morral; J.Ägren. Acta Materialia 1997, 45, pp. 1189-99. 11. W.D.Hopfe; J.E.Morral. Acta Metallurgica Et Materialia 1994, 42, pp. 3887. 12. Kaufman, L.; Bernstein, H. Computer Calculation of Phase Diagrams, Academic Press: New York, 1970. 13. W.Huang; Y.A.Chang. Intermetallics 1999, 7, pp. 863-74. 14. B.Sundman; B.Jansson; J-O Andersson. Calphad 1985, 9, pp. 153-90. 15. C.E.Campbell; J-C Zhao; M.F.Henry. Journal of Phase Equilibria and Diffusion 2004, 25, pp. 6-15. 16. J.-O Andersson; L.Höglund; B.Jönsson; J.Ägren. Fundamentals and Applications of Ternary Diffusion, Pergamon Press: New York, 1990. 17. N.Saunders Superalloys 1996, 1996 TMS; pp. 101. 18. C.E.Campbell; W.J.Boettinger; U.R.Kattner. Acta Materialia 2002, 50, pp. 775-92. 19. Cheng Jin; J.E.Morral. Scripta Materialia 1997, 37, pp. 621-26. 37 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 20. C.W.Yeung; W.D.Hopfe; J.E.Morral; A.D.Romig Jr. Materials Science Forum 1994, 163-165, pp. 189-94. 21. M.A.Dayananda; J.A.Nesbitt TMS-AIME Fall Meeting, Detroit, MI, 1984 pp. 195-230. 22. M.A.Dayananda. Metallurgical and Materials Transactions A 1983, 14A, pp. 1851-58. 23. C.W.Kim; M.A.Dayananda. Metallurgical and Materials Transactions A 1983, 14A, pp. 857-64. 24. M.A.Dayananda; C.W.Kim. Metallurgical and Materials Transactions A 1979, 10A, pp. 1333-39. 25. Matano, C. Japanese Journal of Physics 1932, 8, pp. 109. 26. J.A.Nesbitt. NASA/TM-2000-209271 2000. 27. Visual Numerics. IMSLTM Numerical Libraries Family of Products. http://www.vni.com/products/imsl/index.html . 2004. 28. D.W.Marquardt. Journal of the Society for Industrial and Applied Mathematics 1963, 11, pp. 431-41. 29. A.T.Dinsdale. Calphad 1991, 15, pp. 317-425. 38 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 9 Appendices 9.1 Tables Table 3 Nominal composition of selected alloys and coatings GTD 111 René-88 IN-718 GT-33 GT-29 Ni BAL BAL BAL 32 -- C 0.1 0.03 0.008 --- Cr 14 16 19 21 29 Co 9.5 13 -BAL BAL Al 3 2.1 0.5 10 6 Composition wt% Ti Mo W 4.9 1.5 3.8 3.7 4 4 0.9 3 -------- Nb -0.7 5.1 --- Ta 2.8 ----- Zr 0.01 0.03 ---- B 0.01 ---0.0015 Y --0.5 0.6 Table 4 Samples available for analysis NiCoCrAlY/Ni-base Coating: GT-33 Alloy: DS GTD-111 Mount Couple No. 35C 1691 35E 2287 35F 3188 35H 1485 35I 1682 35J 1897 35N 1444 35O 1462 35P 1533 35Q 1643 35T 1423 35U 1453 35V 1524 CoCrAlY/Ni-base Coating: GT-29 Alloy: GTD-111 Mount Couple No. 58C 1698 58E 2294 58F 3195 58H 1492 58I 1689 58J 1904 58N 1451 58O 1469 58P 1540 58Q 1650 58T 1430 58U 1460 58V 1531 Diffusion Temperature, °C(°F) Diffusion time, (hrs.) 865 (1589) 865 (1589) 865 (1589) 940 (1724) 940 (1724) 940 (1724) 990 (1814) 990 (1814) 990 (1814) 990 (1814) 1050 (1922) 1050 (1922) 1050 (1922) 1959 8698 17054 492 1980 4512 119 324 711 1338 187 343 736 39 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 9.2 Selected Micrographs Figure 24 Optical micrograph of sample 1691 Figure 25 Optical micrograph of sample 1897 40 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 9.3 Concentration Profiles 80 Concentration (wt%) 70 60 50 Ni Co Cr Al 40 30 20 10 0 -200 -100 0 100 200 Distance from original interface (µm) Figure 26 Concentration profile for sample 1691 80 Concentration (wt%) 70 60 Ni Co Cr Al 50 40 30 20 10 0 -200 -100 0 Distance from original interface (µm) 100 Figure 27 Concentration profile for sample 2287 41 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 80 Concentration (wt%) 70 60 Ni Co Cr Al 50 40 30 20 10 0 -200 -100 0 100 200 300 Distance from original interface (µm) Figure 28 Concentration profile for sample 3188 80 Concentration (wt%) 70 60 Ni Co Cr Al 50 40 30 20 10 0 -200 -100 0 100 200 Distance from original interface (µm) Figure 29 Concentration profile for sample 1485 42 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 70 Concentration (wt%) 60 Ni Co Cr Al 50 40 30 20 10 0 -200 -100 0 100 Distance from original interface (µm) 200 Figure 30 Concentration profile for sample 1682 70 Concentration (wt%) 60 Ni Co Cr Al 50 40 30 20 10 0 -200 -100 0 100 Distance from original interface (µm) 200 Figure 31 Concentration profile for sample 1897 43 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 80 Concentration (wt%) 70 Ni Co Cr Al 60 50 40 30 20 10 0 -200 -100 0 100 200 Distance from original interface (µm) Figure 32 Concentration profile for sample 1444 80 Concentration (wt%) 70 60 50 Ni Co Cr Al 40 30 20 10 0 -200 -100 0 100 200 300 Distance from original interface (µm) Figure 33 Concentration profile for sample 1462 44 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 70 Concentration (wt%) 60 Ni Co Cr Al 50 40 30 20 10 0 -150 -50 50 150 250 Distance from original interface (µm) Figure 34 Concentration profile for sample 1533 80 Concentration (wt%) 70 60 Ni Co Cr Al 50 40 30 20 10 0 -200 -100 0 100 200 Distance from original interface (µm) Figure 35 Concentration profile for sample 1423 45 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 80 Concentration (wt%) 70 60 Ni Co Cr Al 50 40 30 20 10 0 -200 -100 0 100 200 Distance from original interface (µm) Figure 36 Concentration profile for sample 1453 80 Concentration (wt%) 70 60 Ni Co Cr Al 50 40 30 20 10 0 -200 -100 0 100 200 Distance from original interface (µm) Figure 37 Concentration profile for sample 1524 46 Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University 9.4 IMSL program input file TEMPERATURE 990 TIME 324 CO 150 33.36 1 110 33.93 1 90 33.79 1 70 32.78 1 50 30.89 1 40 29.43 1 30 30.84 1 20 29.63 1 -10 32.57 1 -20 29.81 1 -30 20.94 1 -40 12.36 1 -50 10.18 1 -70 9.13 1 -90 9.86 1 -110 9.8 1 -150 10.31 1 -200 9.43 1 -300 10.44 1 -500 9.54 1 CR 150 18.15 1 110 9.03 1 90 19.24 1 70 19.58 1 50 16.77 1 40 15.07 1 30 17.29 1 20 16.18 1 -10 20.06 1 -20 17.63 1 -30 9.02 1 -40 11.65 1 -50 11.37 1 -70 11.67 1 -90 12.34 1 -110 12.09 1 -150 12.5 1 -200 10.99 1 -300 12.83 1 -500 11.53 1 AL 150 10.43 1 110 9.43 1 90 9.25 1 70 8.85 1 50 11.03 1 40 12.12 1 30 10.23 1 20 11.81 1 -10 7.4 1 -20 9.17 1 -30 7.13 1 -40 4.82 1 -50 4.48 1 -70 3.58 1 -90 3.34 1 -110 3.56 0.5 -150 3.08 0.5 -200 3.44 0.5 -300 3.06 0.5 -500 3.35 0.5 TEMPERATURE 940 TIME 492 CO 150 35.04 2 120 37.22 2 90 36.47 2 60 33.54 2 40 33.38 2 30 34.28 2 20 33.5 2 10 31.27 2 -10 36.2 2 -20 19.49 2 -30 12.31 2 -40 10.76 1 -60 10.45 1 -90 10.49 1 -120 9.8 1 -150 9.46 1 CR 150 18.22 1 120 20.23 1 90 20.17 1 60 17.57 1 40 18.05 1 30 19.02 1 20 18.78 1 10 15.81 1 -10 22.35 1 -20 8.19 1 -30 11.97 1 -40 12.42 1 -60 13.66 1 -90 13.34 1 -120 12.36 1 47 -150 12.05 1 AL 150 5.25 1 120 4.42 1 90 4.35 1 60 5.01 1 40 4.79 1 30 4.34 1 20 4.62 1 10 5.71 1 -10 2.08 1 -20 3.22 1 -30 2.06 1 -40 1.43 1 -60 1.27 1 -90 1.29 1 -120 1.35 1 -150 1.28 1 TEMPERATURE 1050 TIME 736 CO 150 26.92 1.5 100 27.08 1.5 70 28.45 1.5 50 28.51 1.5 30 27.95 1.5 20 28.59 1.5 10 31.6 1.5 -10 29.58 1.5 -20 30.44 1.5 -30 28.19 1.5 -60 19.28 1.5 -80 14.94 1.5 -100 10.88 1.5 -150 9.62 1.5 -200 9.87 1.5 CR 150 14.91 1 100 15.16 1 70 16.28 1 50 16.5 1 30 16.31 1 20 16.83 1 10 19.76 1 -10 19.67 1 -20 20.27 1 -30 20.01 1 -60 10.55 1 -80 9.6 1 Tuesday, September 06, 2005 Richard Meguerian -100 9.85 1 -150 10.89 1 -200 12.14 1 AL 150 12.11 1 100 11.72 1 70 10.9 1 50 10.34 1 30 10.35 1 20 9.19 1 10 6.63 1 -10 6.04 1 -20 5.89 1 -30 5.84 1 -60 7.6 1 -80 6.67 1 -100 5.98 1 -150 4.89 1 -200 3.57 1 TEMPERATURE 865 TIME 1959 CO 90 32.6 2 60 32.21 2 40 36.26 2 30 33.94 2 20 31.87 2 10 31.19 2 -10 22.64 2 -20 12.08 2 -30 10.32 1 -40 10.72 1 -60 9.33 1 -90 9.53 1 -120 9.54 1 -150 9.85 1 CR 90 16.22 2 60 16.77 2 40 20.44 2 30 19 2 20 16.57 10 16.35 2 -10 11.88 2 -20 10.9 2 -30 12.24 2 -40 12.96 2 -60 12.7 2 -90 11.92 2 -120 12.33 2 -150 12.03 2 AL TMS Outstanding Student Paper Contest 2005 McMaster University -250 13.67 1 -300 13.04 1 90 7.92 1 60 7.67 1 40 5.4 1 30 6.25 1 20 7.14 1 10 7.17 1 -10 3.58 1 -20 2.87 1 -30 2.07 1 -40 1.79 1 -60 1.84 1 -90 1.86 1 -120 1.63 1 -150 1.71 1 TEMPERATURE 865 TIME 17054 CO 150 31.43 2 120 34.39 2 80 31.59 2 60 35.03 2 40 30.9 2 30 34.46 2 20 33.12 2 10 34.15 2 -10 37.83 2 -20 21.01 2 -30 12.19 1 -50 10.98 1 -80 8.94 1 -100 9.63 1 -130 9.07 1 -160 10.37 1 -200 10.75 1 -250 10.7 1 -300 10.57 1 CR 150 16.12 1 120 19.9 1 80 16.61 1 60 20.65 1 40 15.67 1 30 19.23 1 20 19.38 1 10 19.69 1 -10 23.97 1 -20 11.49 1 -30 11.74 1 -50 12.19 1 -80 10.27 1 -100 11.87 1 -130 14.43 1 -160 13.2 1 -200 13.34 1 48 AL 150 6.3 0.5 120 4.87 0.5 80 6.2 0.5 60 4.44 0.5 40 6.43 0.5 30 4.8 0.5 20 5.03 0.5 10 4.82 0.5 -10 2.46 0.5 -20 3.46 0.5 -30 2.52 0.5 -50 1.71 0.5 -80 1.55 0.5 -100 1.79 0.5 -130 1.47 0.5 -160 1.43 0.5 -200 1.49 0.5 -250 1.46 0.5 -300 1.55 0.5 TEMPERATURE 940 TIME 4512 CO 150 29.81 1.5 100 30.36 1.5 70 33.23 1.5 50 28.52 1.5 30 32.93 1.5 20 32.29 1.5 10 34.93 1.5 -10 35.56 1.5 -20 24.61 1.5 -30 13.98 1 -50 11.66 1 -70 9.92 1 -100 10.3 1 -150 10.45 1 CR 150 16.33 1 100 15.68 1 70 19.15 1 50 14.54 1 30 18.83 1 20 18.22 1 10 21.76 1 -10 22.68 1 -20 11.36 1 -30 12.96 1 -50 12.48 1 -70 11.96 1 -100 13.78 1 Tuesday, September 06, 2005 Richard Meguerian -150 12.81 1 AL 150 5.69 0.5 100 5.73 0.5 70 4.41 0.5 50 6.47 0.5 30 4.17 0.5 20 4.31 0.5 10 3.18 0.5 -10 2.5 0.5 -20 3 0.5 -30 2.43 0.5 -50 1.66 0.5 -70 1.6 0.5 -100 1.25 0.5 -150 1.44 0.5 TEMPERATURE 990 TIME 119 CO 150 36.82 1.5 100 37.34 1.5 70 32.71 1.5 50 34.81 1.5 30 33.81 1.5 20 31.02 1.5 10 30.03 1.5 -10 32.54 1.5 -20 21.41 1 -30 12.06 1 -50 10.17 1 -70 10.58 1 -100 10.45 1 -150 8.94 1 CR 150 19.69 1 100 21.07 1 70 16.74 1 50 19.5 1 30 19.37 1 20 17.8 1 10 16.86 1 -10 21.87 1 -20 10.66 0.5 -30 12.37 0.5 -50 13.96 0.5 -70 13.33 0.5 -100 12.99 0.5 -150 10.47 0.5 AL 150 5.45 0.5 100 4.64 0.5 70 6.34 0.5 TMS Outstanding Student Paper Contest 2005 McMaster University 50 5 0.5 30 4.77 0.5 20 5.39 0.5 10 5.86 0.5 -10 2.49 0.5 -20 3.3 0.5 -30 2.28 0.5 -50 1.53 0.5 -70 1.41 0.5 -100 1.51 0.5 -150 1.48 0.5 TEMPERATURE 990 TIME 711 CO 100 31.5 1.5 70 32.24 1.5 50 31.33 1.5 30 31.65 1.5 20 30.07 1.5 10 32.48 1.5 -10 29.69 1.5 -20 22.6 1.5 -30 14.32 0.5 -50 11.07 0.5 -70 10.25 0.5 -100 9.88 0.5 -150 9.54 0.5 -200 10.8 0.5 CR 100 15.94 1 70 18.01 1 50 16.65 1 30 17.64 1 20 16.04 1 10 18.08 1 -10 16.13 1 -20 12.61 1 -30 9.82 1 -50 13.23 1 -70 13.18 1 -100 12.57 1 -150 11.32 1 -200 13.29 1 AL 100 6.68 0.5 70 5.46 0.5 50 6.01 0.5 30 5.7 0.5 20 6.07 0.5 10 4.68 0.5 -10 5.17 0.5 -20 3.29 0.5 -30 3 0.5 49 -50 1.72 0.5 -70 1.66 0.5 -100 1.46 0.5 -150 1.58 0.5 -200 1.62 0.5 TEMPERATURE 940 TIME 1980 CO 100 32.07 2 70 33.29 2 50 30.39 2 30 30.92 2 20 30.87 2 10 31.02 2 -10 32.11 2 -20 16.99 1 -30 13.28 1 -50 10.18 1 -70 10.35 1 -100 8.79 1 CR 100 17.52 1.5 70 18.25 1.5 50 15.93 1.5 30 16.39 1.5 20 16.54 1.5 10 16.97 1.5 -10 19.02 1.5 -20 9.57 1 -30 11.26 1 -50 13.35 1 -70 13.43 1 -100 10.76 1 AL 100 6.84 0.5 70 5.74 0.5 50 7.36 0.5 30 7.15 0.5 20 6.67 0.5 10 6.51 0.5 -10 4.19 0.5 -20 3.95 0.5 -30 2.65 0.5 -50 1.95 0.5 -70 1.87 0.5 -100 1.74 0.5 TEMPERATURE 865 TIME 8698 CO 150 36.47 2 120 32.65 2 Tuesday, September 06, 2005 Richard Meguerian 90 35.27 2 60 33.75 2 40 34.6 2 30 33.59 2 20 32.57 2 10 34.05 2 -10 38.68 2 -20 25.76 2 -30 16 2 -40 12.57 1 -80 10.71 1 CR 150 20.32 2 120 16.03 2 90 18.94 2 60 17.77 2 40 19.06 2 30 17.25 2 20 16.79 2 10 18.1 2 -10 24.01 2 -20 11.62 1 -30 11.55 1 -40 15.48 1 -80 13.31 1 AL 150 2.74 0.5 120 3.96 0.5 90 3.18 0.5 60 3.67 0.5 40 3.23 0.5 30 3.78 0.5 20 3.85 0.5 10 3.42 0.5 -10 1.4 0.5 -20 2.05 0.5 -30 1.76 0.25 -40 1.38 0.25 -80 0.94 0.25 TEMPERATURE 1050 TIME 187 CO 150 32.48 2 100 32.32 2 TMS Outstanding Student Paper Contest 2005 McMaster University 70 33.03 2 50 31.62 2 30 33.07 2 20 32.3 2 10 30.41 2 -10 30.84 2 -20 31.71 2 -30 26.37 2 -50 16.42 1 -70 11.93 1 -100 10.91 1 -150 10.34 1 150 31.01 2 100 33.67 2 70 30.15 2 50 30.32 2 30 32.67 2 20 32.49 2 10 31.42 2 -10 32.67 2 -20 33.48 2 -30 32.14 2 -50 30.33 2 -70 20.4 2 -100 13.21 1.5 -150 10.51 1.5 CR 150 17.19 2 100 17.68 2 70 18.66 2 50 17.26 2 30 18.45 2 20 18.96 2 10 16.83 2 -10 18.83 2 -20 20.29 2 -30 18.18 2 -50 11.12 2 -70 11.97 2 -100 13.36 2 -150 13.01 2 AL 150 3.88 0.5 100 3.74 0.5 70 2.85 0.5 50 3.49 0.5 30 2.96 0.5 20 3.01 0.5 10 3.6 0.5 -10 2.69 0.5 -20 1.85 0.5 -30 1.4 0.5 -50 1.94 0.5 -70 1.57 0.5 -100 1.09 0.25 -150 1.03 0.25 TEMPERATURE 1050 TIME 343 CO CR 150 16.56 2 100 19.52 2 70 15.92 2 50 16.27 2 30 18.47 2 20 18.78 2 10 17.94 2 -10 19.59 2 -20 21.67 2 -30 20.1 2 -50 20.16 2 -70 10.46 2 -100 12.27 2 -150 13.92 2 AL 150 4.13 0.5 100 2.87 0.5 70 4.1 0.5 50 3.87 0.5 30 3.15 0.5 20 2.9 0.5 10 3.13 0.5 -10 2.55 0.5 -20 2.19 0.5 -30 2.53 0.5 -50 1.76 0.5 -70 2.29 0.5 -100 1.66 0.5 -150 1.12 0.5 9.5 Thermo-Calc TDB File $ Database file written $ ELEMENT VA VACUUM ELEMENT AL FCC ELEMENT CR BCC ELEMENT NI FCC 5- 2-21 0.0000E+00 2.6982E+01 5.1996E+01 5.8690E+01 50 0.0000E+00 4.5400E+03 4.0500E+03 4.7870E+03 0.0000E+00! 2.8300E+01! 2.3543E+01! 2.9796E+01! Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University FUNCTION GALFCC 2.98140E+02 -7976.15+137.093038*T-24.3671976*T*LN(T) -.001884662*T**2-8.77664E-07*T**3+74092*T**(-1); 7.00000E+02 Y -11276.24+223.048446*T-38.584296*T*LN(T)-.018531982*T**2 -5.764227E-06*T**3+74092*T**(-1); 9.33600E+02 Y -11278.378+188.684153*T-31.748192*T*LN(T)-1.231E+28*T**(-9); 2.90000E+03 N ! FUNCTION GALHCP 2.98150E+02 +5481-1.8*T+GALFCC#; 6.00000E+03 N ! FUNCTION GALLIQ 2.98140E+02 +GALFCC#+11005.029-11.841867*T +7.934E-20*T**7; 9.33470E+02 Y +GALFCC#+10482.382-11.253974*T+1.231E+28*T**(-9); 2.90000E+03 N ! FUNCTION GALBCC 2.98140E+02 +GALFCC#+10083-4.813*T; 2.90000E+03 N ! FUNCTION GCRBCC 2.98140E+02 -8856.94+157.48*T-26.908*T*LN(T) +.00189435*T**2-1.47721E-06*T**3+139250*T**(-1); 3.11500E+02 Y -8856.94+157.48*T-26.908*T*LN(T)+.00189435*T**2-1.47721E-06*T**3 +139250*T**(-1); 2.18000E+03 Y -34869.344+344.18*T-50*T*LN(T)-2.88526E+32*T**(-9); 6.00000E+03 N ! FUNCTION GCRHCP 2.98150E+02 +4438+GCRBCC#; 6.00000E+03 N ! FUNCTION GCRLIQ 2.98140E+02 +GCRBCC#+24335.955-11.420225*T +2.37615E-21*T**7; 2.18000E+03 Y +GCRBCC#+18409.36-8.563683*T+2.88526E+32*T**(-9); 6.00000E+03 N ! FUNCTION GCRFCC 2.98150E+02 +GCRBCC#+7284+.163*T; 6.00000E+03 N ! FUNCTION GNIFCC 2.98140E+02 -5179.159+117.854*T-22.096*T*LN(T) -.0048407*T**2; 1.72800E+03 Y -27840.655+279.135*T-43.1*T*LN(T)+1.12754E+31*T**(-9); 3.00000E+03 N ! FUNCTION GNIHCP 2.98150E+02 +1046+1.2552*T+GNIFCC#; 6.00000E+03 N ! FUNCTION GNILIQ 2.98140E+02 +GNIFCC#+16414.686-9.397*T -3.82318E-21*T**7; 1.72800E+03 Y +GNIFCC#+18290.88-10.537*T-1.12754E+31*T**(-9); 3.00000E+03 N ! FUNCTION GNIBCC 2.98140E+02 +GNIFCC#+8715.084-3.556*T; 3.00000E+03 N ! FUNCTION UN_ASS 2.98140E+02 0.0 ; 3.00000E+02 N ! FUNCTION UALCR 2.98150E+02 7910; 6.00000E+03 N ! FUNCTION UCRNI 2.98140E+02 -3831; 3.00000E+03 N ! FUNCTION UALNI 2.98140E+02 -14556.4+2.945*T; 2.90000E+03 N ! TYPE_DEFINITION % SEQ *! DEFINE_SYSTEM_DEFAULT SPECIE 2 ! DEFAULT_COMMAND DEF_SYS_ELEMENT VA ! TYPE_DEFINITION & GES A_P_D BCC MAGNETIC PHASE BCC %& 1 1.0 ! CONSTITUENT BCC :AL,CR,NI : ! PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER REF:0 ! PARAMETER REF:0 ! PARAMETER -1.0 4.00000E-01 ! G(BCC,AL;0) 2.98140E+02 +GALBCC#; 2.90000E+03 N REF:0 ! G(BCC,CR;0) 2.98150E+02 +GCRBCC#; 6.00000E+03 N REF:0 ! TC(BCC,CR;0) 2.98150E+02 -311.5; 6.00000E+03 N REF:0 ! BMAGN(BCC,CR;0) 2.98150E+02 -.01; 6.00000E+03 N REF:0 ! G(BCC,NI;0) 2.98140E+02 +GNIBCC#; 3.00000E+03 N REF:0 ! TC(BCC,NI;0) 2.98140E+02 575; 3.00000E+03 N REF:0 ! BMAGN(BCC,NI;0) 2.98140E+02 .85; 3.00000E+03 N REF:0 ! G(BCC,AL,CR;0) 2.98140E+02 -54900+10*T; 2.90000E+03 N REF:0 ! G(BCC,AL,CR,NI;0) 2.98140E+02 -100000; 2.90000E+03 N REF:0 ! G(BCC,AL,NI;0) 2.98140E+02 -50000+11*T; 2.90000E+03 N REF:0 ! G(BCC,CR,NI;0) 2.98140E+02 +17170-11.8199*T; 3.00000E+03 N G(BCC,CR,NI;1) TC(BCC,CR,NI;0) 2.98140E+02 2.98140E+02 51 +34418-11.8577*T; 2373; 3.00000E+03 3.00000E+03 N N REF:0 ! Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University PARAMETER TC(BCC,CR,NI;1) 2.98140E+02 617; 3.00000E+03 N REF:0 ! PARAMETER BMAGN(BCC,CR,NI;0) 2.98140E+02 4; 3.00000E+03 N REF:0 ! PHASE AL11CR2 % 3 10 CONSTITUENT AL11CR2 1 2 ! :AL : AL : CR : ! PARAMETER G(AL11CR2,AL:AL:CR;0) 2.98150E+02 -175500+25.805*T +11*GALFCC#+2*GCRBCC#; 6.00000E+03 N REF:0 ! PHASE AL13CR2 % 2 13 CONSTITUENT AL13CR2 2 ! :AL : CR : ! PARAMETER G(AL13CR2,AL:CR;0) 2.98150E+02 +2*GCRBCC#; 6.00000E+03 N REF:0 ! PHASE AL3NI1 % 2 .75 .25 ! CONSTITUENT AL3NI1 :AL : NI : PARAMETER G(AL3NI1,AL:NI;0) +.25*GNIFCC#; 6.00000E+03 PHASE AL3NI2 % 3 3 CONSTITUENT AL3NI2 -174405+22.2*T+13*GALFCC# ! 2.98150E+02 N REF:0 ! -40463+5.312*T+.75*GALFCC# 2 1 ! :AL : AL,NI% : NI,VA% : ! PARAMETER G(AL3NI2,AL:AL:NI;0) 2.98150E+02 -41219+2.792*T+5*GALBCC# +GNIBCC#; 6.00000E+03 N REF:0 ! PARAMETER G(AL3NI2,AL:NI:NI;0) 2.98150E+02 -428055+71.808*T+3*GALBCC# +3*GNIBCC#; 6.00000E+03 N REF:0 ! PARAMETER G(AL3NI2,AL:AL:VA;0) 2.98150E+02 +30000-3*T+5*GALBCC#; 6.00000E+03 N REF:0 ! PARAMETER G(AL3NI2,AL:NI:VA;0) 2.98150E+02 -356836+66.079*T+3*GALBCC# +2*GNIBCC#; 6.00000E+03 N REF:0 ! PARAMETER G(AL3NI2,AL:AL,NI:NI;0) 2.98150E+02 -38157; 6.00000E+03 REF:0 ! PARAMETER G(AL3NI2,AL:AL:NI,VA;0) 2.98150E+02 -23319; 6.00000E+03 REF:0 ! PARAMETER G(AL3NI2,AL:NI:NI,VA;0) 2.98150E+02 -23319; 6.00000E+03 REF:0 ! PARAMETER G(AL3NI2,AL:AL,NI:VA;0) 2.98150E+02 -38157; 6.00000E+03 REF:0 ! PHASE AL3NI5 % 2 .375 .625 ! CONSTITUENT AL3NI5 :AL : NI : PARAMETER G(AL3NI5,AL:NI;0) +.625*GNIFCC#; 6.00000E+03 PHASE AL4CR % 2 4 CONSTITUENT AL4CR 5 ! :AL : CR : PARAMETER G(AL8CR5_H,AL:CR;0) N N -54795+5.292*T+.375*GALFCC# ! PARAMETER G(AL4CR,AL:CR;0) 2.98150E+02 +GCRBCC#; 6.00000E+03 N REF:0 ! PHASE AL8CR5_H % 2 8 CONSTITUENT AL8CR5_H N ! 2.98150E+02 N REF:0 ! 1 ! :AL : CR : N -89025+19.05*T+4*GALFCC# ! 2.98150E+02 52 -147732-58.5*T+8*GALFCC# Tuesday, September 06, 2005 Richard Meguerian +5*GCRBCC#; TMS Outstanding Student Paper Contest 2005 McMaster University 6.00000E+03 PHASE AL8CR5_L % 2 8 CONSTITUENT AL8CR5_L N REF:0 ! 5 ! :AL : CR : PARAMETER G(AL8CR5_L,AL:CR;0) 6.00000E+03 N REF:0 ! PHASE AL9CR4_H % 2 9 CONSTITUENT AL9CR4_H ! 2.98150E+02 4 ! :AL : CR : ! PARAMETER G(AL9CR4_H,AL:CR;0) 2.98150E+02 +4*GCRBCC#; 6.00000E+03 N REF:0 ! PHASE AL9CR4_L % 2 9 CONSTITUENT AL9CR4_L 4 ! :AL : CR : 2 ! :AL : CR : -230750+16.094*T+9*GALFCC# ! PARAMETER G(ALCR2,AL:CR;0) 2.98150E+02 +2*GCRBCC#; 6.00000E+03 N REF:0 ! PHASE BETA % 2 1 CONSTITUENT BETA -134433-56.16*T+9*GALFCC# ! PARAMETER G(AL9CR4_L,AL:CR;0) 2.98150E+02 +4*GCRBCC#; 6.00000E+03 N REF:0 ! PHASE ALCR2 % 2 1 CONSTITUENT ALCR2 -229515+8*GALFCC#+5*GCRBCC#; -32700-8.79*T+GALFCC# 1 ! :AL,CR,NI : CR,NI,VA : ! PARAMETER G(BETA,AL:CR;0) 2.98140E+02 +GALBCC#+GCRBCC#; 2.90000E+03 N REF:0 ! PARAMETER G(BETA,CR:CR;0) 2.98150E+02 +100+2*GCRBCC#; 6.00000E+03 N REF:0 ! PARAMETER G(BETA,NI:CR;0) 2.98140E+02 +GCRBCC#+GNIBCC#+7000; 3.00000E+03 N REF:0 ! PARAMETER G(BETA,AL:NI;0) 2.98140E+02 +GALBCC#+GNIBCC#-152685+23.936*T; 3.00000E+03 N REF:0 ! PARAMETER G(BETA,CR:NI;0) 2.98140E+02 +GCRBCC#+GNIBCC#+7000; 3.00000E+03 N REF:0 ! PARAMETER G(BETA,NI:NI;0) 2.98140E+02 +2*GNIBCC#; 3.00000E+03 N REF:0 ! PARAMETER G(BETA,AL:VA;0) 2.98140E+02 +GALBCC#+10000-T; 2.90000E+03 N REF:0 ! PARAMETER G(BETA,CR:VA;0) 2.98150E+02 +GCRBCC#+20000; 6.00000E+03 N REF:0 ! PARAMETER G(BETA,NI:VA;0) 2.98140E+02 +GNIBCC#+162508-24.936*T; 3.00000E+03 N REF:0 ! PARAMETER G(BETA,AL,NI:CR;0) 2.98140E+02 -47306+4.909*T; 2.90000E+03 N REF:0 ! PARAMETER G(BETA,AL:CR,VA;0) 2.98140E+02 -10000; 2.90000E+03 N REF:0 ! PARAMETER G(BETA,AL:CR,NI;0) 2.98140E+02 -10000; 2.90000E+03 N REF:0 ! PARAMETER G(BETA,CR,NI:CR;0) 2.98140E+02 10000; 3.00000E+03 N REF:0 ! PARAMETER G(BETA,CR,NI:CR;1) 2.98150E+02 10000; 6.00000E+03 N REF:0 ! PARAMETER G(BETA,CR:CR,VA;0) 2.98150E+02 200000; 6.00000E+03 N REF:0 ! PARAMETER G(BETA,CR:CR,NI;0) 2.98140E+02 10000; 3.00000E+03 N REF:0 ! PARAMETER G(BETA,CR:CR,NI;1) 2.98150E+02 10000; 6.00000E+03 N REF:0 ! PARAMETER G(BETA,NI:CR,VA;0) 2.98140E+02 200000; 3.00000E+03 N REF:0 ! PARAMETER G(BETA,NI:CR,NI;0) 2.98140E+02 10000; 3.00000E+03 N REF:0 ! 53 Tuesday, September 06, 2005 Richard Meguerian PARAMETER PARAMETER N REF:0 ! PARAMETER N REF:0 ! PARAMETER N REF:0 ! PARAMETER PARAMETER PARAMETER N REF:0 ! PARAMETER N REF:0 ! PARAMETER N REF:0 ! PARAMETER PARAMETER TMS Outstanding Student Paper Contest 2005 McMaster University G(BETA,NI:CR,NI;1) G(BETA,AL,NI:NI;0) 2.98150E+02 2.98140E+02 10000; 6.00000E+03 N REF:0 ! -47306+4.909*T; 2.90000E+03 G(BETA,AL,CR:NI;0) 2.98140E+02 +28660-39.38*T; G(BETA,AL:NI,VA;0) 2.98140E+02 -62755+29.622*T; G(BETA,CR,NI:NI;0) G(BETA,CR,NI:NI;1) G(BETA,CR:NI,VA;0) 2.98140E+02 2.98150E+02 2.98140E+02 10000; 3.00000E+03 N REF:0 ! 10000; 6.00000E+03 N REF:0 ! -62755+29.622*T; 3.00000E+03 G(BETA,NI:NI,VA;0) 2.98140E+02 -62755+29.622*T; G(BETA,AL,NI:VA;0) 2.98140E+02 -47306+4.909*T; G(BETA,CR,NI:VA;0) G(BETA,CR,NI:VA;1) 2.98140E+02 2.98150E+02 10000; 10000; PHASE DISORD % 1 1.0 ! CONSTITUENT DISORD :AL,CR,NI : PARAMETER PARAMETER PARAMETER PARAMETER REF:0 ! PARAMETER PARAMETER REF:0 ! PARAMETER REF:0 ! PARAMETER PARAMETER REF:0 ! PARAMETER N REF:0 ! 2.90000E+03 3.00000E+03 2.90000E+03 3.00000E+03 N REF:0 ! 6.00000E+03 N REF:0 ! ! G(DISORD,AL;0) 2.98140E+02 +GALFCC#; 2.90000E+03 N REF:0 ! G(DISORD,CR;0) 2.98150E+02 +GCRFCC#; 6.00000E+03 N REF:0 ! G(DISORD,NI;0) 2.98140E+02 +GNIFCC#; 3.00000E+03 N REF:0 ! G(DISORD,AL,CR;0) 2.98140E+02 -45850+6*T; 2.90000E+03 N G(DISORD,AL,CR,NI;0) 2.98140E+02 96489; 2.90000E+03 N REF:0 ! G(DISORD,AL,NI;0) 2.98140E+02 -16367+12*UALNI#; 2.90000E+03 N G(DISORD,AL,NI;1) 2.98140E+02 +2023+39.894*T; G(DISORD,AL,NI;2) G(DISORD,CR,NI;0) 2.98140E+02 2.98140E+02 84175; 2.90000E+03 N REF:0 ! +8030-12.87*T; 3.00000E+03 N G(DISORD,CR,NI;1) 2.98140E+02 +33080-16.0362*T; TYPE_DEFINITION ' GES A_P_D FCC MAGNETIC PHASE FCC %' 1 1.0 ! CONSTITUENT FCC :AL,CR,NI : ! PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER REF:0 ! PARAMETER REF:0 ! PARAMETER PARAMETER REF:0 ! PARAMETER PARAMETER PARAMETER REF:0 ! PARAMETER REF:0 ! 2.90000E+03 -3.0 2.90000E+03 N 3.00000E+03 2.80000E-01 ! G(FCC,AL;0) 2.98140E+02 +GALFCC#; 2.90000E+03 N REF:0 ! G(FCC,CR;0) 2.98150E+02 +GCRFCC#; 6.00000E+03 N REF:0 ! TC(FCC,CR;0) 2.98150E+02 -1109; 6.00000E+03 N REF:0 ! BMAGN(FCC,CR;0) 2.98150E+02 -2.46; 6.00000E+03 N REF:0 ! G(FCC,NI;0) 2.98140E+02 +GNIFCC#; 3.00000E+03 N REF:0 ! TC(FCC,NI;0) 2.98140E+02 633; 3.00000E+03 N REF:0 ! BMAGN(FCC,NI;0) 2.98140E+02 .52; 3.00000E+03 N REF:0 ! G(FCC,AL,CR;0) 2.98140E+02 -45900+6*T; 2.90000E+03 N REF:0 ! G(FCC,AL,CR,NI;0) 2.98140E+02 -853+16.245*T; 2.90000E+03 N G(FCC,AL,NI;0) 2.98140E+02 -168343+16*T; 2.90000E+03 N G(FCC,AL,NI;1) G(FCC,AL,NI;2) 2.98140E+02 2.98140E+02 34311; 2.90000E+03 N REF:0 ! +4162+27.29*T; 2.90000E+03 N TC(FCC,AL,NI;0) 2.98140E+02 -1112; 2.90000E+03 N REF:0 ! TC(FCC,AL,NI;1) 2.98140E+02 1745; 2.90000E+03 N REF:0 ! G(FCC,CR,NI;0) 2.98140E+02 +8030-12.8801*T; 3.00000E+03 N G(FCC,CR,NI;1) 2.98140E+02 54 +33080-16.0362*T; 3.00000E+03 N Tuesday, September 06, 2005 Richard Meguerian TMS Outstanding Student Paper Contest 2005 McMaster University PARAMETER TC(FCC,CR,NI;0) 2.98140E+02 -3605; 3.00000E+03 N REF:0 ! PARAMETER BMAGN(FCC,CR,NI;0) 2.98140E+02 -1.91; 3.00000E+03 N REF:0 ! PHASE LIQUID % 1 1.0 ! CONSTITUENT LIQUID :AL,CR,NI : PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER N REF:0 ! PARAMETER PARAMETER N REF:0 ! PARAMETER REF:0 ! PARAMETER N REF:0 ! ! G(LIQUID,AL;0) 2.98140E+02 +GALLIQ#; 2.90000E+03 N REF:0 ! G(LIQUID,CR;0) 2.98150E+02 +GCRLIQ#; 6.00000E+03 N REF:0 ! G(LIQUID,NI;0) 2.98140E+02 +GNILIQ#; 3.00000E+03 N REF:0 ! G(LIQUID,AL,CR;0) 2.98140E+02 -29000; 2.90000E+03 N REF:0 ! G(LIQUID,AL,CR;1) 2.98140E+02 -11000; 2.90000E+03 N REF:0 ! G(LIQUID,AL,CR,NI;0) 2.98140E+02 8257; 2.90000E+03 N REF:0 ! G(LIQUID,AL,NI;0) 2.98140E+02 -197088+30.353*T; 3.00000E+03 G(LIQUID,AL,NI;1) G(LIQUID,AL,NI;2) 2.98140E+02 2.98140E+02 5450; 2.90000E+03 N REF:0 ! +54624-11.383*T; 2.90000E+03 G(LIQUID,CR,NI;0) 2.98140E+02 +318-7.3318*T; G(LIQUID,CR,NI;1) 2.98140E+02 +16941-6.3696*T; 3.00000E+03 N 3.00000E+03 $ THIS PHASE HAS A DISORDERED CONTRIBUTION FROM DISORD TYPE_DEFINITION ( GES AMEND_PHASE_DESCRIPTION ORD DIS_PART DISORD,,,! PHASE ORD %( 2 .75 .25 ! CONSTITUENT ORD :AL,CR,NI : AL,CR,NI : ! PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER PARAMETER G(ORD,AL:AL;0) 2.98140E+02 0.0 ; 2.90000E+03 N REF:0 ! G(ORD,CR:AL;0) 2.98140E+02 +3*UALCR#; 2.90000E+03 N REF:0 ! G(ORD,NI:AL;0) 2.98140E+02 +3*UALNI#; 2.90000E+03 N REF:0 ! G(ORD,AL:CR;0) 2.98140E+02 +3*UALCR#; 2.90000E+03 N REF:0 ! G(ORD,CR:CR;0) 2.98140E+02 0.0 ; 2.90000E+03 N REF:0 ! G(ORD,NI:CR;0) 2.98140E+02 +3*UCRNI#; 3.00000E+03 N REF:0 ! G(ORD,AL:NI;0) 2.98140E+02 +3*UALNI#; 2.90000E+03 N REF:0 ! G(ORD,CR:NI;0) 2.98140E+02 +3*UCRNI#; 3.00000E+03 N REF:0 ! G(ORD,NI:NI;0) 2.98140E+02 0.0 ; 3.00000E+03 N REF:0 ! G(ORD,AL,CR:*;0) 2.98140E+02 +6*UALCR#; 2.90000E+03 N REF:0 ! G(ORD,AL,NI:*;0) 2.98140E+02 +6*UALNI#; 2.90000E+03 N REF:0 ! G(ORD,CR,NI:*;0) 2.98140E+02 +6*UCRNI#; 3.00000E+03 N REF:0 ! PHASE SIGMA % 3 8 4 18 ! CONSTITUENT SIGMA :NI : CR : CR,NI : ! PARAMETER G(SIGMA,NI:CR:CR;0) 2.98150E+02 +221157-227*T+8*GNIFCC# +4*GCRBCC#+18*GCRBCC#; 6.00000E+03 N REF:0 ! PARAMETER G(SIGMA,NI:CR:NI;0) 2.98150E+02 +175400+8*GNIFCC#+4*GCRBCC# +18*GCRBCC#; 6.00000E+03 N REF:0 ! LIST_OF_REFERENCES NUMBER SOURCE ! 55 Tuesday, September 06, 2005