The martensitic phase transformation (MPT) is one of the most important factors that enhances the surface roughening of stainless-steel thin metal foils (TMF), such as SUS 304, compared to others without MPT, even in the same plastic strain. However, the conventional roughening model does not take into account the influence of MPT. In this study, the authors proposed a new constitutive model to express the surface roughening by taking the influence of MPT into account. The volume fractions of MPT for TMF of SUS304 in various grain sizes are accounted for quantitatively after the tensile test at room temperature and an elevated temperature, and the effect of MPT on the surface roughening is evaluated in comparison to using TMF of SUS316, in which MPT does not occur during plastic deformation. Then, a constitutive model of the surface roughening based on the experimental results is successfully built.
Keywords: martensitic phase transformation (MPT); surface roughening; work hardening (n).