Mechanical study of crystalline orientation distribution in Ti-6Al-4V: An assessment of micro-texture induced load partitioning

Microtextured regions are known to have a detrimental effect on the fatigue performance of near alpha and alpha/beta titanium alloys. Due to the elastic anisotropy of a titanium, stress heterogeneities are expected to result from such microstructural features. The present work is an assessment of their influence on the elastic stress field, using Fast Fourier Transform-based computations on a 2D extruded aggregate built from a real microstructure. The contribution of the microtextured regions was then isolated by comparing simulations obtained on a synthetic aggregate with similar grain morphology and texture but removed microtextured regions through a redistribution of crystalline orientations. The analysis of the computed fields revealed that the average stress experienced by a grains is only weakly affected by the neighborhood and mostly determined by the elastic anisotropy of a titanium. Nevertheless, complex mechanical interactions between microtextured regions were evidenced. Indeed, load partitioning and non-local influence on the stress field were found to result from the presence of microtextured regions. The implications on fatigue crack initiation are discussed in light of these results. (C) 2017 Elsevier Ltd. All rights reserved.