Mechanical Anisotropy of Selective Laser Melted Ti-6Al-4V Using a Reduced-order Crystal Plasticity Finite Element Model

Abstract

In this study, a reduced-order crystal plasticity finite element (CPFE) model was developed to study the effects of the microstructural morphology and crystallographic texture on the mechanical anisotropy of selective laser melted (SLMed) Ti-6Al-4V. First, both hierarchical and equiaxed microstructures in columnar prior grains were modeled to examine the influence of the microstructural morphology on mechanical anisotropy. Second, the effects of crystallographic anisotropy and textural variability on mechanical anisotropy were investigated at the granular and representative volume element (RVE) scales, respectively. The results show that hierarchical and equiaxed CPFE models with the same crystallographic texture exhibit the same mechanical anisotropy. At the granular scale, the significance of crystallographic anisotropy varies with different crystal orientations. This indicates that the present SLMed Ti-6Al-4V sample with weak mechanical anisotropy resulted from the synthetic effect of crystallographic anisotropies at the granular scale. Therefore, combinations of various crystallographic textures were applied to the reduced-order CPFE model to design SLMed Ti-6Al-4V with different mechanical anisotropies. Thus, the crystallographic texture is considered the main controlling variable for the mechanical anisotropy of SLMed Ti-6Al-4V in this study.