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Highly Alloyed Titanium Alloys Produced by Low Cost Blended Elemental Powder Metallurgy
ApproachM.V.Matviychuk1, V.S.Moxson1 , V.A.Duz1,
O.M. Ivasishin2, D.G. Savvakin 21‐ADMA Products, Inc. Hudson, OH, USA2‐Institute for Metal Physics, Kiev, Ukraine
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Presentation overview
• PM BE approach for manufacturing the Ti alloys from TiH2 powder
• Highly‐alloyed Ti compositions (beta alloys)• High‐strength alloy Ti‐1Al‐8V‐5Fe shortoverview
• As‐sintered Properties of Ti‐1Al‐8V‐5Fe• Improvement of as‐sintered microstructure forTi‐1Al‐8V‐5Fe
• Effect of heat treatment (HT) and thermomechanical processing (TMP)
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PM BE approach for manufacturing the Ti alloys from TiH2 powder
TiH2, Alloying ElementsPowders
Blending Compaction Sintering
N Alloy Porosity, %
Grain Size, mkm
YS, MPA UTS, MPA El,%
1 Cp‐Ti 1 120 495 605 21
2 Ti‐6Al‐4V
1.5 150 885 975 12
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Highly alloyed Ti compositions (beta alloys)
Widely used in aerospace, automotive and other industries due to:
‐ highest strength/density ratio among all titanium alloys
‐ mechanical properties can be changed within wide range by heat treatment
‐ homogeneous microstructure and properties within large cross sections
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Peculiarities of highly alloyed Ti compositions sintering
- higher content of alloying elements (higher volume part of master alloys)- more complicated phase transformations (e.g. high sensitivity to cooling conditions)- complicated chemical homogenization- increased residual porosity (up to 5%)
Process developed for alloys needed opt
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PM BE approach for manufacturing the highly alloyed Ti alloys from TiH2powder
Porosity, % GrainSize,μm
YS, MPa UTS,MPa
El., % RA, %
As‐sintered 2 82 1005 1100 10.6 17.9
STA 2 82 1115 1250 5.2 11.0
Porosity, % GrainSize,μm
YS, MPa UTS,MPa
El., % RA, %
As‐sintered 1.5 100 1140 1244 4.87 9.21
Aging 1.5 100 1200 1304 6.8 10.3
Ti‐10V‐2Fe‐3Al
Ti‐5Al‐5V‐5Mo‐3Cr
TiH2, Alloying ElementsPowders
Blending Compaction Optimize Sintering
Heat Treatment
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• Is it possible to produce the high‐strength Ti alloys with UTS>1400 MPA by Powder Metallurgy?
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Highly alloyed Ti‐compositions• Ti‐1Al8V5Fe – a high‐strength alloy developed in 1950’s
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YS, MPA UTS, MPA El,% RA, %
1380 1448 6.0 12.0
Guaranteed STA room‐temperature properties
V Al Fe O N C Fe
7.5‐8.5 0.8‐1.3 4.0‐6.0 0.25‐0.5
0.07 0.05 4.0‐6.0
Chemical compositions
Beta Transus: 830 oC
Effect of STA on tensile propertiesMaterials Properties HandbookTitanium Alloysedited by Gerhard Welsch
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TTT diagrams
Mo eq. 1023 = 9.5
Mo eq. 5553 =8.15Mo eq. 185 = 18 James D. Cotton,
Proceedings of 11th World
Conference on
Titanium Ti‐2007 (Kyoto, Japan). ‐pp.471‐475
D. Eylon,Beta Titanium Alloys in the 1990's
Materials Properties Handbook: Titanium Alloys edited by Gerhard Welsch
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Effect of alloying elements on shrinkage
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0 200 400 600 800 1000 1200 1400
-0,10
-0,08
-0,06
-0,04
-0,02
0,00
0,02
L/
L
Temperature, °C
CpTiTi-185
Ti-5553Ti-1023
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As‐sintered Microstructure of Ti‐185TiH2, Alloying
ElementsPowders
Blending Compaction Sintering
‐Low tensile properties‐High brittleness‐Porosity 3%
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Improvement of as‐sintered microstructure and properties
Regime
Porosity, %
Grain size, mkm
T1 2.5 110-137
T2 1.9 136-204
T3 2.7 126-166
T4 2.55 156-217
Porosity,%
GrainSize,μm
YS,MPa
UTS, MPa El.,%
RA,%
Oxygen,%
Regularsintering
3 50 ‐ 875 ‐ ‐ 0.4
Low poroussint.
1.9 160 862 925 ‐ ‐ 0.33
Ti‐1Al‐8V‐5Fe
T1
T2
T3
T4
TiH2, Alloying ElementsPowders
Blending Compaction Low porousSintering
T1
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Thermo‐Mechanical processing of Ti‐1Al‐8V‐5Fe
Ø=90mm
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Ø=16mmHot rolling
TiH2, Alloying ElementsPowders
Blending Compaction Sintering Post Processing
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Density: 97%100%
Effect of thermo‐mechanical processing on improvement of mechanical
properties of Ti‐185
As‐sintered As‐rolled
YS, MPa UTS, MPa El., %
As-Sintered 857 ± 15
As-Rolled 1192 ± 13 1283 ± 12 18 ± 1.5
Rolled + STA1
1489 ± 6 1535 ± 4 5 ± 1.0
Rolled + STA2
1620 ±16
1668 ± 15 4.7 ± 0.8
Rolled + STA3
1654 ±10
1689 ± 13 4 ± 1.8
The total reduction ratio for the rod‐rolling process was 31:1
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RBF S‐N curves of Ti‐185
The RBF was conducted at 10,000 RPM or166.6 Hz.
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Optimized properties
YS, MPa UTS, MPa El., %
As-Sintered 857 ± 15As-Rolled 1192 ± 13 1283 ± 12 18 ± 1.5
Rolled + STA4 1585 1654 8
Guaranteed STAroom‐temperature
properties1380 1448 6
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Conclusion• Highly‐alloyed titanium compositions with strength more
then 1400 MPa (Ti‐1Al‐8V‐5Fe) can be successfully sinteredvia a novel low cost powder metallurgy route using titaniumhydride powder. It is especially important in case of alloysthat are difficult to produce via ingot metallurgy.
• The microstructures of Ti‐1Al‐8V‐5Fe were homogeneousacross the entire cross section, and no segregation wasobserved.
• The controlled formation of fine grains, reduced porosityduring alloy sintering, properly selected post‐sintering heattreatment and thermo‐mechanical processing parametersallow attainment of desirable properties meeting highstrength requirements.
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