結晶塑性セルフコンシステント法を用いたfcc金属材料の加工集合組織予測とTaylorの均一ひずみ仮定との比較

抄録

A viscoplastic self-consistent (VPSC) numerical model for deformation texture prediction been developed and applied to the plane strain compression problems of the high temperature austenite steels having fcc lattice structure. Using the VPSC model, the parameter study of the strain rate sensitivity exponent (m-value) was conducted and the results were compared with those by an extended Taylor model (the viscoplastic constitutive law is employed while uniform strain assumption over grains in the representative volume element is adopted) and by the hot rolling experiments using Fe-70Ni fcc metal. Despite the small underestimation of brass texture, the results by VPSC model have revealed that m = 0.02 case successfully reproduced the similar texture with the experimental ones of 650 °C hot rolled Fe-70Ni sample, while m = 0.2 case reproduced 850 °C hot rolled sample texture. By contrast, the extended Taylor model overestimated the copper texture for any parameter cases. Therefore, the simulated deformation textures by the VPSC model agree better than those by the extended Taylor model. In addition, the effect of deformation magnitude on the texture formation has been analysed by using the VPSC model. The results find the more pronounced copper texture with increasing compressive strain, which agrees with the experimental results.