Prof. Priit Kulu
Outline
1. High-strength structural steels
2. High-performance tool steels
3. Metallic-ceramic materials
4. Light-weight metals and alloys
5. Superalloys
Advanced metallic materials
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Advanced metallic materials
Metallic materials with
superior properties
Superconductive NbTi, Nb3Sn, Nb3Ge
Neodymium rare-earth magnets (alloys
of Nd, Fe and B) are strongest known
permanent magnets. Sm-Co magnets
Structural alloys
Mg- and Al-alloys with superior
properties, Al-metaglass, foams
Ti-alloys with thermomechanical
properties, superalloys, maraging steels,
intermetallides, high-density alloys,
shape-memory alloys
Amorphous alloys with chemical and
thermal properties, Ni- and Fe
aluminates
Biocompatible Ti-alloys
Advanced metallic materials
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Strength groups of materials
Classification based on tensile strength (Rm) of materials
I.
II.
III.
IV.
Low-strength (<250 N/mm2)
Mid-strength (250...750 N/mm2)
High-strength (750...1500 N/mm2)
Ultrahigh-strength (<1500 N/mm2)
Advanced metallic materials
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Production
technologies of
hihg-strength
steels and
alloys
Advanced metallic materials
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1. High-strength structural steels
2. High-performance tool steels
3. Metallic-ceramic materials
4. Light-weight metals and alloys
5. Superalloys
Advanced metallic materials
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High-strength steel
...what
is it?
The end of 1920-s
Steel St 52 (S355) for bridge construction 
Today
S355 is standard grade
 Definition for “high-strength” is dependent on
level of development.
Steel ReH > 355 MPa
Advanced metallic materials
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1.
2.
3.
4.
5.
6.
Methods
for increasing strength
structure refinement
alloying – B; microalloying elements – Nb, Ti, V and N
low carbon steels  transgranular fracture
two- and multi-phase structures – F+M; F+M+B
dispersion strengthening – micro- and nanosteels
deformation
hardening:
Alloying of ferrite
- low- & high-temperature
Hardening
- isothermal
- marforming
Alloying elements, %
Advanced metallic materials
Ageing
Ageing time, t
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Heat treatable boron-steels
≈ 0,003% of B  increased through-hardenability
 0,002...0,003% of B in solid solution has the same
effect on hardenability than 0,7% Cr; 0,5% Mo or 1% Ni
Through-hardenability  diameter up to 200 mm
C24CR Rp0,21000; Rm1500; A 7%
Advanced metallic materials
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Low-alloy high-strength steels
Also known as HSLA steels
 C = 0,2..0,3% ; alloying el: Mn, Si
 Micro alloying with Nb, Ti and/or V –
dispersion strengthening + grain refinement
HX340LAD
HX460LAD
 Rp0,2560; Rm640 N/mm2; A – min 15%
Advanced metallic materials
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Two- and multi-phased steels
Also known as duplex (DP) and complex (CP) steels
Ultra-High-strength (UHS) ductile steels
-
Two-phase LITEC DP Rp0,2750 N/mm2; Rm980 N/mm2;
A – min 10%
Advanced metallic materials
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- Multi-phase LITEC CP Rp0,2900; Rm980 N/mm2; A – 7%
DP-steel
CP-steel
→ good formability and high strength
→ ability of high energy absorption
→ high strain-hardening rate
→ good fatigue strength
Advanced metallic materials
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Maraging (martensite-ageing) steels (1)
Martensitic steels ( C%)
- low ductility and toughness in case of high Rm
- M decomposition, formation of carbide phase 
brittleness
Maraging steels in 1980
- low C-content (0,03%)  transgranular fraction
- alloying el. – Ni (17...25%), Mo + Ti, Al, Ta etc.
Quenching  C-free martensite,
Ageing  intermetallides (4 – 5) nm, (NiTi, Ni3Ti, NiAl,
Ni3Mo etc.)
Rm  2000 N/mm2, Rp0,2  1500 N/mm2, A = 10 - 12%
Advanced metallic materials
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Maraging steels (2)
Advanced metallic materials
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Termomechanically processed /
deformation hardened
high temperature
low temperature
isothermal
marforming
Advanced metallic materials
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Thermomechnical rolling
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TRIP-steels (Transformation Induced
Plasticity)
 Low alloy steels (car industry)
0,2 – 0,3 % C; 1,5 – 2,0 % Mn, Si + Al
 High alloy Ni-Cr steeks
0,2 – 0,3 % C; 8 – 32 % Ni; 8 – 14 % Cr+Mn (0,5 – 2,5%), Mo, Si
Quenching (985 – 1200 °C) → F, B, A
Deformation (< Trecr = 250 – 550 °C), A → M
Rm →1700, Rp0,2 → 1550, A =50 – 60 %, ↑KIC, σ-1
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Strength-plasticity of high-strength steels
Rp0,2 N/mm2
KTMT
TMT + def. ageing
2000
TRIP-steels
TMT + def. ageing
Maraging
steels (highalloy)
1000
Low-alloy steels
20
40
60
60
A%
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1. High-strength structural steels
2. High-performance tool steels
3. Metallic-ceramic materials
4. Light-weight metals and alloys
5. Superalloys
Advanced metallic materials
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Advanced tool steels (1)
I generation of high-speed steels (HSS)
 carbide temper hardness steels
500 - 650 0C, e.g. HS 6 – 5 – 2 – 5
W-Mo -V –Co
 Intermetallic temper hardness steels
650 - 750 0C, Co7W6, (CoFe)7W6 etc.
(11 – 20%)W; 7% Mo; (1-3%)V; (20 – 25%)Co
Structure (cast and rolled)
Advanced metallic materials
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Advanced tool steels (2)
II generation of high-speed steels – PM steels (PM/HIP)
Uddeholmi steels Vanadis 4, 6, 10, 23, 30, 60 (Super
Clean) (1,3 - 2,9%) C; → 6,5 W; (1,5 - 7%) Mo; (3,1 - 9,8%) V;
→ 10,5% Co
Structure (PM / HIPed)
Advanced metallic materials
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Advanced tool steels (3)
III generation of high-speed steels – Sprayformed,
SF + HIP PM steels,
Vanadis 4 EXTRA
WEARTEC
2,8 C; 8,9 V; 7,0 Cr; 2,3 Mo; Si; Mn
ROLTEC
1,4C; 4,6Cr; 3,7 V; 3,2 Mo; Si; Mn
TOUGHTEC
1,6C; 7,2V; 5,0 Cr; 2,3 Mo; Si; Mn
Advanced metallic materials
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SF /HIP
Similar to PM/HIP, slab
formation by spraying
methods
High-Tech Materials & Technologies
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Strength of high-speed steels
TRZ, GPa
Diameter of carbide particles, m
Advanced metallic materials
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1. High-strength structural steels
2. High-performance tool steels
3. Metallic-ceramic materials
4. Light-weight metals and alloys
5. Superalloys
Advanced metallic materials
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Classification of wear resistant materials
depending on volumetric content of hard phase
Advanced metallic materials
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Metallic-ceramic composites
Carbide steels and alloys
 Ferro-TiC
Steel (50 - 70)% -TiC
 Double-reinforced MMC
(Cr-steel + 20%VC) + 20%WC
 Self-fluxing alloys
NiCrSiB +  50% (WC-Co)
Ceramic/metallic
 TiC-NiMo – (50 - 60)% (NiMo)(2:1) 920 – 1620 HV10
 Cr3C2-NiCr – (50 - 60)% NiCr
Advanced metallic materials
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1. High-strength structural steels
2. High-performance tool steels
3. Metallic-ceramic materials
4. Light-weight metals and alloys
5. Superalloys
Advanced metallic materials
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Light-weight materials – Mg alloys
Mg-alloys (Mg:  = 1740 kg/m3, Ts – 649 0C)
Alloying elements: Al (3 - 10%); Zn, up to (5 – 6%); Mn; Zr
Rm  300 N/mm2 (deformable alloys)
220 N/mm2 (cast alloy)
Advanced metallic materials
Rm/  20
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Light-weight materials – Al alloys
Al-alloys
 Al-Li alloys (Li is only dopant, which  Rm, E,
however  = 2500 kg/m3)
2Li, 4Mg,  Rm = 220 – 350; Rp0,2 = 135 – 210 N/mm2
 Powder-aluminum-alloys
- dispersion strengthened Al-alloys (SAP-Al2O315%, Al-
C-alloys – Al4C3 20 volume%), allowed working
temperature up to 550 0C
 Foam-aluminum ( ~ 200 kg/m3)
Advanced metallic materials
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1. High-strength structural steels
2. High-performance tool steels
3. Metallic-ceramic materials
4. Light-weight metals and alloys
5. Superalloys
Advanced metallic materials
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Superalloys
…alloys capable of service at high temperatures, usually
above 1000 °C
→ heat-resistant high-temperature strength alloys
 Ni-alloys
 Co-alloys
heat resistance (oxidation resistance > 600°C)
refractory steels = heat res. + high temp. strength
Advanced metallic materials
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Ni-alloys
Ni uses: ca
60% – stainless steels
12% – Ni-alloys
10% – coatings
10% – alloy steels
Heat resistant alloys (superalloys)
 wrought (Inconel Ni – 20-23 Cr; Hastelloy Ni- 7-22 Cr-Co)
 cast ( polycrystalline, directionally solidified, single crystal)
 PM (HIP-ed, IN 100, Rene 95→ gasturbine disk)
718 (cast) Ni – (4,75 – 5,5%) Nb → aerospace, nuclear structural
applications (-250 – +700 °C).
MA 754 PM/HIP Ni – 1% Y2O3
Advanced metallic materials
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Co-alloys
Co uses: ca
46% – superalloys
15% – steels
10% – cemented carbides
Wear resistant alloys
 Stellite – Co (10 –30%); Cr (1,5 –22) Ni; up to 15% W; 1 Mo
Heat resistant alloys
 wrought Co + (20 –30%) Cr; (14 –15%) W
 cast Co +(23 –29%) Cr; (1 –10 %) Ni; 7 W
Corrosion resistant alloys
Ultimet Co + 26Cr; 9Ni; 5Mo; 2W
Advanced metallic materials
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General stress-rupture behaviour of
superalloys
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TUT materials engineering web-site:
www.ttu.ee/mti
mti@ttu.ee
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