マルテンサイト変態に関する基底ベクトルを用いたラス組織形成のPhase-field・結晶塑性解析

抄録

According to a report that TRIP steels can achieve both strength and ductility by deformation-induced martensitic transformation, an optimum microstructure and nucleation timing may be obtained by simulating tensile deformation and microstructure formation of TRIP steels through numerical analysis. However, there is currently no model that describes the deformation process of TRIP steel based on crystal plasticity FEM. In this report, we first derive the basis vectors of the martensitic transformation based on the phenomenological theory of the crystal habit plane in the martensitic transformation, to express the transformation strain rate in the crystal plasticity form. In particular, dealing with lath martensite, the basis vectors are calculated for each of the 24 martensitic variants using the double shear model. Then, the crystal plasticity model and the multi-phase-field model are coupled to reproduce the formation of lath martensite microstructure under tensile loading. In the analysis using basis vectors of 6 martensitic variants, it is showed that the block structure of lath martensite is numerically formed.