微視力を考慮した結晶塑性FEMによる単結晶TRIP鋼に生じる寸法依存マルテンサイト変態の検討

抄録

Strain-induced martensitic transformation (SIMT) plays an essential role in generating the outstanding mechanical properties of TRIP steels such as strength, toughness and ductility. Therefore, deep understanding of the SIMT at microstructural scale is very important to predict and control accurately the superior macroscopic mechanical properties of TRIP steel. In the past, it is predicted that the austenitic grain size influence strongly the expected properties by the generalized model for the kinetics of SIMT. Additionally, martensitic embryo nucleates heterogeneously due to the dislocation initiating inhomogeneously on slip systems during plastic deformation. The complicated nucleation of martensite is of course size-dependent. Hence, it is necessary to have a good approach to describe martensitic transformation phenomenon including specific length scale. In this study, a developed continuum crystal plasticity theory including the concept of microforce proposed by Fried and Gurtin is employed in the framework of finite element method in order to simulate the size-dependent martensitic transformation of single crystal TRIP steel.