Anisotropic tensile behaviour of additively manufactured Ti-6Al-4V simulated with crystal plasticity

Abstract

The anisotropic behaviour of laser powder bed fusion (LPBF) Ti-6Al-4V under uniaxial tension is investigated through crystal plasticity simulations. A periodic multi-scale representative volume element (RVE) is calibrated against quasi-static tensile tests carried out on dog-bone specimens, printed in different orientations. This fitting procedure results in an anisotropic crystallographic texture and a minimum set of crystal plasticity constitutive parameters which are able to reproduce the experimental behaviour. The synthetic RVE consists of primary grains with a realistic aspect ratio and an internal lamellar structure, that approximates the α′ martensite microstructure observed in micrographs of as-built Ti-6Al-4V. The Young’s modulus, yield strength, and hardening behaviour observed experimentally, could be precisely captured using a very limited number of model parameters. Thereby, this work contributes to a deeper understanding of the interplay between micro-structure and macroscopic behaviour, and with a new set of crystal plasticity parameters specific for α′ dominated LPBF Ti-6Al-4V.