Anisotropy of strength and plasticity in single-colony lamellar structure of Ti-6Al-4V alloy

Micro-tensile tests were performed on single-colony specimens to elucidate the anisotropic slip behaviour in Ti-6Al-4V alloy with a lamellar microstructure. The critical resolved shear stress (CRSS) of < c + a > pyramidal slip was more than 1.5 times higher than that of < a > slip. The CRSSes of (a) slips increased with increasing length fraction of beta phase along the slip direction, revealing that the beta phase acts as a hard phase for soft orientations. The < c + a > pyramidal slip with beta laths exhibited a low CRSS value compared with that of a Ti-5Al solid solution, suggesting that the beta phase facilitates the < c + a > slip. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.