MCE 230
HW5
(Due April 7th 2025)
Name: _______________________
ID: __________________________
1- Solve Problem 4.1
The equilibrium fraction of lattice sites that are vacant in gold at 800°C is 2.5 × 10−5. Calculate the number of
vacancies (per meter cubed) at 800°C. Assume a density of 18.45 g/cm3 for Au (at 800°C).
2- Solve Problem 4.7
Which of the following systems (i.e., pair of metals) would you expect to exhibit complete solid solubility? Explain
your answers.
(A) Cr-V
(A) Mg-Zn
(A) Al-Zr
3- Solve Problem 4.17
What is the composition, in atom percent, of an alloy that contains 99.7 lb m copper, 102 lbm zinc, and 2.1 lbm lead.
4- Solve Problem 4.18
Convert the atom percent composition in Problem 4.17 to weight percent
5- Solve Problem 4.36
Cite the relative Burgers vector–dislocation line orientations for edge, screw, and mixed dislocations
6- Solve Problem 4.41
(a) Briefly describe a twin and a twin boundary.
(b) Cite the difference between mechanical and annealing twins.
7- Solve Problem 4.43
(a) Using the intercept method determine the mean intercept length, in millimeters, of the specimen whose
microstructure is shown in Figure 4.15b; use at least seven straight-line segments.
(b) Estimate the ASTM grain size number for this material.
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