Multi-Scale modelling of structure-property relationship in additively manufactured metallic materials

Abstract

This paper presents a multi-scale modelling framework to evaluate the structure-property relationship of metallic materials fabricated by powder-bed additive manufacturing (AM) technique based on crystal plasticity finite element methods. In this framework, a new synthetic microstructure generation approach is proposed to reconstruct micro-scale models of AMed metals according to the characteristics of grain growth in the fabrication process. The constitutive relation of individual grains in the micro-scale reconstructed models is described with the single-crystal-scale plasticity model. Meanwhile, to reduce the computational cost, a polycrystal-scale plasticity model is also established. The homogeneous elastic moduli tensor is computed according to Mori-Tanaka's theory, while the plastic deformation is described by the equivalent grain set. The proposed multi-scale modelling framework is validated against experiments, where the as-built Ti-6Al-4V samples fabricated by selective laser melting (SLM) are tested under uniaxial tensile, compressive, and cyclic loadings. The presented experimental and computational study demonstrates the capability of the proposed multi-scale modelling framework in the structure-property analysis of AMed metals.