Crystal plasticity approach for predicting mechanical responses of porous wire-arc directed energy deposited Al4043 structure

This study presents an integrated experimental and computational approach to predict the mechanical properties of wire-arc directed energy deposited (DED) aluminum 4043 (Al4043) structure. Thermo-metallurgical simulation has been performed to identify a deposition strategy that reduces heat accumulation during the deposition process. Based on the simulation results, a raster deposition strategy and a lower interpass temperature (50 °C) have been maintained during the fabrication to minimize temperature buildup and promote microstructural homogeneity. Electron backscatter diffraction (EBSD) analysis and mechanical testing with digital image correlation reveal the presence of isotropic mechanical properties (difference is less than 4%). Porosity, commonly present in the wire-arc DED Al4043 structures, has been quantified using X-ray micro-computed tomography (X-CT). Representative volume elements (RVEs) are generated utilizing EBSD data from two perpendicular planes and pore size distribution from X-CT. The phenomenological crystal plasticity (CP) framework has been utilized to simulate deformation behavior and study local stress-strain behavior considering the effect of grain statistics and porosity. The CP model parameters are calibrated and validated utilizing an iterative Bayesian optimization framework by matching simulated stress-strain curves with tensile test data along the build direction and deposition direction, respectively. Calibration result indicates discrepancy of 1.42% for yield strength and 1.11% for ultimate tensile strength, whereas model validation shows discrepancies of 2.85% and 1.45%, respectively, for the corresponding values. The CP simulations reveal a high level of consistency in the local stress–strain response across the RVEs, further supporting the presence of a homogenous structure.