二元系Ti-Nb合金のHCP相割合と圧縮塑性変形挙動の関係に関する一考察

抄録

Binary titanium alloys are often composed of several phases. The phase fraction changes with content of alloying element and influences on mechanical properties. In this study, solution treated metastable binary titanium-niobium alloys with different niobium content were prepared and their uniaxial and biaxial compressive plastic deformation behaviors were investigated, focusing on the ratios of α (hexagonal close packed structure) and β (body centered cubic structure) phases. It was revealed that α phase gradually decreased and β phase increased with increasing niobium content. The primary plastic deformation mechanism changed from crystal slip to stress induced martensite transformation and deformation twinning with the change of phase fractions. The increase of β phase lowered the compressive stress and thus, the relationship between the phase fraction and the compressive plastic deformation behavior was discussed.