Elucidating the influence of temperature and strain rate on the mechanics of AFS-D through a combined experimental and computational approach

Abstract

In this study, the temperature and strain rate dependent physics of Additive Friction Stir Deposition (AFS-D) are elucidated for the first time. Candidate constitutive models are selected to account for the severe plastic deformation and wide ranges of temperature and strain rate inherent to AFS-D. Torsion mechanical tests are performed to capture AA6061 stress dependency on temperature and strain rate. Four constitutive models, including a low fidelity-calibrated one, are applied to single-layer AFS-D simulations. The robust meshfree method, smoothed particle hydrodynamics (SPH), provided the framework for constitutive model comparison. Utilizing the SPH simulations, peak values, temperature contours, effective stress contours, effective plastic strain contours, build profiles, and simulation run time are all compared to reveal hidden mechanisms of AFS-D processing. This work highlights the importance of constitutive model selection, which can lead to improved simulation results by accurately capturing plastic stress dependence on strain, strain rate, and temperature.