Crystallographic orientation dependent crack nucleation during the compression of a widmannstatten-structure α/β titanium alloy

Based on the observation on slip trace and crystallographic orientation, the corresponding slip system, Schmid factor (SF) and geometric compatibility parameter (m') around the crack were calculated during compression of a widmannstatten-structure alpha/beta titanium alloy. The difficult slip transfer, mainly occurring at a low m', induces a stress concentration on the grain boundary alpha (alpha(GB)) and at the junction of several alpha colonies in the beta grain, and then arouses a corresponding crack nucleation. The alpha(GB)-alpha colony boundary, alpha-beta interface, colony-colony boundary and slip plane could act as the crack propagation ways according to the different crack nucleation site. (C) 2018 Acta Materialia Inc Published by Elsevier Ltd. All rights reserved.