Crystallographic Study of Diffusion Phase Transformations for Martensites with Complex Structure

复杂结构马氏体扩散相变的晶体学研究

基本信息

批准号：
03452243
负责人：
OTSUKA Kazuhiro
金额：
$ 4.42万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

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.

对于韦克斯勒·莱伯曼·雷德（Wechsler-Lieberman-Read）和鲍尔斯·马肯齐（Bowles-Mackenzie）开发了一种精美的现象学理论，用于传播相变的晶体学相关。但是，仍然存在合金，尚未确定转换的晶体学。当前工作的目的是详细研究它们，并获得马氏体转变的统一观点。我们在ni-al合金中选择了b2-> 14m（7r）转换，beta_2（b2） - > zeta_2'（trigonal）转换AU-49.5AT％CD合金，例如这种情况。首先，我们发现现象学晶体学理论非常适用于B2-> 14m转换。还研究了合金的自我适应性，我们提出了一种新的基本形态，称为“平行果形态”，而不是先前提出的“钻石形态”。此外，在Ni-Al-MN合金中，我们发现了指定为10m（15m）和12M（36M）的新的Martensite结构，在其他合金中也没有发现。对于后者的AU-49.5AT％CD合金，我们确定了Zeta_2'Martensite的结构，该结构未确定为50年。在beta_2-> Zeta_2'转换上，Ledbetter假设存在晶格不变剪切，而Tadaki等人则构成了存在。在本研究中，我们发现了两种称为屋顶型和鲱鱼骨的马氏体形态，其中前者具有不变的剪切，而后者则没有。因此，我们调和了两个研究人员之间的极大不一致。从上面的结果中，我们得出的结论是，如果正确选择了晶格不变的剪切，即使选择正确的剪切剪切，现象学晶体学理论也适用于具有复杂结构的马氏体。