Strain accommodation of <110>-normal direction-oriented grains in micro-shear bands of high-purity tantalum

Abstract

The <110>ND (<110>//normal direction)(<110>ND) grains in micro-shear bands in high-purity tantalum were investigated using electron backscatter diffraction and X-ray line profile analysis. The generation of the <110>ND grains and their subdivision and rotation behaviors upon the subsequent deformation were characterized by multi-scale analysis methods based on information about the slip systems, misorientation angle/axes and stored energy. The obtained results show that in the transverse plane, <110>ND grains are oriented at angles of 15°–25° to the adjacent deformed matrices in the 60% rolled specimen, and at angles of 25°–35° in the 87% rolled specimen. The <110>ND grain provided strain accommodation during the shear deformation. Moreover, the energy of the <110>ND grains in the 87% rolled specimen is approximately three times larger than that in the 60% rolled specimen, indicating that the role of strain accommodation is enhanced with the increase in the micro-shear stress concentration in a local region in tantalum.