Y. Yasumoto, K. Hashimoto, M. Matsuda, Kumamoto University, Kumamoto, Japan; T. Fukuda, T. Kakeshita, Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan; M. Nishida, Kyushu University, Kasuga, Japan
It has been widely recognized that the lattice invariant shear of martensite with layered structure such as 9R or 18R martensites is stacking faults on (001) basal plane. Therefore, internal twins are boundaries of martensite plate variants, which are so-called “variant accommodation twins”. The variant accommodation twin is introduced as a result of mutual accommodation of shear strains between variants in the martensite. For 9R and/or 18R martensites, many researchers have reported that there are four plate variants commonly designated as A, B, C and D, and three fundamental plate variant combinations can be identified in a given plate variant; designated as A : B (C : D), A : C (B : D) and A : D (B : C) types. The intervariant boundaries of these three types are in Type II, Type I and compound twin relations, respectively. These are also classified to three features, i. e., spear, wedge and fork-like morphologies, respectively. However, there is no investigation on the variant combinations in the 10M and the 14M martensites in the Ni-Mn-Ga alloys as far as we know. In the present paper we will present the variant combinations in the layered martensites in the Ni-Mn-Ga alloy.
Summary: In the present paper, we will present the variant combinations of 10M and 14M martensites in the Ni-Mn-Ga alloy.
