| Project/Area Number |
03452243
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Physical properties of metals
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| Research Institution | University of Tsukuba |
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Principal Investigator |
OTSUKA Kazuhiro Univ.Tsukuba, Inst.Mat.Sci., Professor, 物質工学系, 教授 (50029881)
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| Co-Investigator(Kenkyū-buntansha) |
OHBA T. Teikyo Univ., Dept.Mat.Sci., Assoc.Prof., 理工学部, 助教授 (00211110)
ODA K. Univ.Tsukuba, Inst.Mat.Sci., Assist.Prof., 物質工学系, 講師 (80177229)
MIYAZAKI S. Univ.Tsukuba, Inst.Mat.Sci., Assoc.Prof., 物質工学系, 助教授 (50133038)
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| Project Period (FY) |
1991 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1993: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1992: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1991: ¥3,500,000 (Direct Cost: ¥3,500,000)
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| Keywords | diffusionaless phase transformation / crystallography phase transformation / phenomenological theory / 7R martensite / Ni-Al / Au-Cd / self-accommodation / lattice invariant shear / マルテンサイト変態 / NiーAl合金 / AuーCol合金 / 形状記憶合金 / マルテンサイト変態の結晶石 / 理象論 / 構造解析 |
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| Research Abstract |
There is a beautiful phenomenological theory for the crystallography of diffusionaless phase transformations called martensitic transformations, which were developed by Wechsler-Lieberman-Read and Bowles-Mackenzie. However, there still remain alloys, for which the crystallography of the transformations are still not yet established. It is the purpose of the present work to study them in detail, and to obtain the unified view for the martensitic transformations. We picked up B2->14M(7R) transformation in Ni-Al alloys and beta_2 (B2)->zeta_2'(trigonal) transformations in a Au-49.5at%Cd alloy as such cases. First, we found that the phenomenological crystallographic theory applies well for the B2->14M transformation. The self-accommodation of the alloy was also studied, and we proposed a new basic morphology called "the parallelogran morphology" instead of the previously proposed "diamond morphology". Furthermore, in Ni-Al-Mn alloys, we found new martensite structures designated as 10M(15M) and 12M(36M), which have not been found in other alloys either. For the latter Au-49.5at%Cd alloy, we determined the structure of the zeta_2' martensite, which have been undetermined for 50years. On the beta_2->zeta_2' transformation, Ledbetter assumed the presence of a lattice invariant shear, while Tadaki et al.deined the presence. In the present study, we found two types of martensite morphologies called roof-type and herring-bone type, in which the former has a lattice invariant shear while the latter does not. Thus, we reconciled the big inconsistency between the two researchers. from the above results, we conclude that the phenomenological crystallographic theory applies well even for the martensites with complex structures, if the lattice invariant shear is chosen correctly.
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