Goss Orientation Evolution in Ti–5.5Mo–8Al–6Zr Shape Memory Alloy upon Heat Treatment

Abstract

The effect of heat treatment temperature on texture formation in Ti5.5Mo8Al6Zr (mol%) alloy sheets was systematically investigated in this study. ¡AA martensite was induced by cold-rolling. Although the deformation texture of ¡AA martensite could not be detected, the formation of f130g ¡ 00 h3 10i ¡ 00 and (100) ¡AA [010] ¡AA textures was proposed. The specimen heat-treated at 1073 K or higher consisted of a single ¢ phase, and Goss, {110} ¢ ©113ª ¢ , and Brass orientations were formed as the recrystallization textures. The Goss orientation, which is irregular for ¢-Ti alloys, developed with increasing heat treatment temperature, and became the dominant component in the specimens heat-treated at 1173 K. The specimen heat-treated at 973 K consisted of the ¢ + ¡ phase. {113} ¢ ©110ª ¢ , {113} ¢ ©141ª ¢ , {223} ¢ ©252ª ¢ , {223} ¢ ©692ª ¢ , and {332} ¢ ©113ª ¢ were formed in the ¢ phase, whereas f11 20g ¡ h1 100i ¡ f11 22g ¡ h1 100i ¡ was formed in the ¡ phase. Transmission electron microscopy observations revealed that the specimen heat-treated at 973 K was not completely recrystallized. This microstructural difference led to a difference in texture components between the specimens heat-treated at 973 K and at 1073 K or higher.