Fe-3mass％Si合金の高温単軸圧縮変形中に生じる優先動的結晶粒成長による集合組織形成に及ぼすP添加の影響

摘要

著者らはこれまでにAl基およびα-Fe基固溶体合金を高温で変形させると，特定方位の結晶粒が変形中に他方位粒を消費しながら優先的に成長することで，室温変形の場合とは異なる集合組織が形成されることを報告した。変形中に特定の結晶方位を持つ結晶粒が優先的に成長することによる集合組織形成は，Al-Mg固溶体合金で初めて確認された。FCCの単軸圧縮変形では，{011生（圧縮面）繊維集合組織が形成されることが知られている。%In order to clarify the effect of solutes on texture formation during high-temperature deformation of BCC solid solution alloys, the texture and microstructure formations in Fe-3.1mass%Si (Fe-Si) and Fe-3.2mass%Si-0.12mass%P (Fe-Si-P) during high-temperature uniaxial compression deformation are studied. The analysis of true stress-true strain curves indicates that the stress exponents at 1173K for Fe-Si-P and Fe-Si are 3.4 and 3.8, respectively. This suggests the addition of phosphorous affects the motion of dislocations. Texture having high axis densities at <001> and <111> are formed both in Fe-Si and Fe-Si-P by the deformation up to a desired strain of 1.0. The volume fraction of <001> oriented region increases and that of <111> oriented region decreases with decreasing strain rate and increasing temperature. This tendency is more obvious in Fe-Si-P than Fe-Si. Microstructural observations by EBSD measurements reveal that the notable increase of the volume fraction of <001> oriented region is attributable to the preferential growth of <001> oriented grains. The growth of <001> oriented grains begins earlier and becomes more active in Fe-Si-P with increasing strain than in Fe-Si. The results suggest that the acceleration of the preferential growth of <001> in Fe-Si-P relates to the dislocation structure affected by the solute atmosphere.