Effects of the Microstructural Grain Size and Aspect Ratio on the Mechanical Properties of Additively Manufactured Parts via Computational Analysis
Published in Defense Technical Information Center, 2021
Metal powder-based additive manufacturing MPAM methods can produce columnar grain microstructures that can vary greatly in size and aspect ratio AR. This can significantly affect the mechanical properties of the resulting part. In an effort to link MPAM process parameters with the structural performance of the manufactured part, the effects of the grain structure on the constitutive response of the material must be determined. This work shows the development, implementation, and application of a microstructure-informed crystal plasticity constitutive model to describe the mechanical behavior of solidified material produced by MPAM. The model accounts for the presence and variability of grain size and AR associated with MPAM. Synthetic representative volume elements RVEs of MPAM-like microstructures from published literature are generated and converted into finite element models from which stress-strain behavior is extracted. Simulation results show that both the size and the AR of the grains have a significant effect on the yield strength and the initial strain hardening modulus.