| Project/Area Number |
62550512
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属材料(含表面処理・腐食防食)
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
KAWABATA Takeshi Institute for Materials Research, Tohoku University, 金属材料研究所, 助教授 (80005983)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1988: ¥100,000 (Direct Cost: ¥100,000)
Fiscal Year 1987: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | TiAl / Mechanical Properties / Ductility Improvement / Strength / Addition of Third Elements / Cr / Hf / Nb / 耐熱合金 / 純度 / 第二相 / 双晶 / 粒界クラック / TiAi / 金属間化合物 / 延性化 / 第三元素添加効果 / 結晶粒微細化 / 双晶発生 / 固溶体強化 |
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| Research Abstract |
The effect of the Ti/Al retio, the addition of third elements (Cr, Hf and Nb) and the use of high purity base metals on mechanical properties of TiAl was studied at room teperature.
1. Effect of the Ti/Al ratio : Strength of Ti-rich alloys was higher than than of Al-rich alloys. Fracture strain (ductility) in Ti-rich alloys was about 1.8 % which was larger than that in Al-rich a alloys being 0.6 % .
2. Effect of third elements : (1) Cr ; Strength increased linearly with increasing Cr content. The alloy with 3 at.% Cr reached two times of that in a binary alloy. The Cr addition of 3 at.% to Ti-rich alloys improved ductility to 2.7 %. The Cr addition to Al-rich alloys lowered ductility.
(2) Hg ; The effect of Hf addition on strength was similar to that in the Cr added alloys. The Hf addition up to 4 at.% to the Ti-rich alloys lowered ductility a little. The Hf eddition to Al-rich alloys decreased ductility to 0.8 %.
(3) Nb ; Strength of the alloy with 3 at.% Nb increased to 2.5 times of that in a binary alloy. On the contrary. No strengthening effect was observed in Al-rich alloys. Ductility in Ti- and Al-rich alloys was decreased to 1/2 due to the Nb addition of 3 at.%.
3. Effect of purity : The use of Ti with 99.91 % purity increased ductility to 2.7 % which has been the highest value in the binary alloys.
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