Effect of Post-Deposition Heat Treatment on the Mechanical Behavior and Deformation Mechanisms of a Solid-State Additively Manufactured Al–Mg–Si Alloy

Abstract

The effects of post-deposition heat treatment on the fatigue behavior of AA6061 processed by additive friction stir deposition (AFSD) were investigated for the first time in this work. A heat treatment to recover the T6 temper was performed on AFSD AA6061 is then subjected to strain-controlled fatigue and monotonic tension testing. Microstructural analysis revealed abnormal grain growth resulting in bimodal grain size distribution. Mechanical testing indicated a full recovery of the strength of the AA6061-T6 temper with comparable fatigue performance to the as-deposited AFSD AA6061. Fractography revealed deformation mechanisms in the post-deposition heat treatment not observed in the as-deposited samples, however, the fatigue resistance remained unchanged. A microstructure-sensitive fatigue model was implemented to capture the effects of the heat treatment process on the fatigue performance of the post-deposition heat-treated AFSD AA6061.