Texture evolution and tensile anisotropy of TC17 alloy β forging pancake

Abstract

Abstract The crystallographic orientations of grain boundary α phase and matrix β phase are two main factors determining the mechanical properties of β forging TC17 alloy. Microstructure and texture evolution of three height reduction pancakes were mainly investigated in this present work by optical microscopy (OM), scanning electron microscopy (SEM), electron back-scattered diffraction (EBSD) combined with Schmid factor analysis and X-ray diffraction (XRD). The results revealed that all pancakes of three height reduction exhibited similar < 001>//forging direction(FD) fiber texture component of β matrix phase whose intensity significantly increased with the increase of height reduction from 20–50%. While the height reduction was up to 70%, intensity basically remained unchanged, but a new texture component (< 011>//FD) was formed possibly due to dynamic recrystallization. The recrystallized grains representing the undeformed or slightly deformed grains affect the texture component of β matrix. Tensile properties of β forging TC17 alloy demonstrated relatively obvious anisotropy. The angle of 45° between forging direction and longitudinal direction indicated the highest strength and lowest ductility, while the longitudinal direction showed higher strength than forging direction. The orientation diversity of grain boundary α phase increased with the increase of height reduction. The specific crystallographic features of grain boundary α phase caused by forging texture affect effective slip length. In addition, their Schmid factor varied significantly with loading direction, possibly leading to tensile anisotropy.