2025 Yang Intrinsic Heat Treatment Al Cu WAAM

Wire arc directed energy deposition (WADED) has emerged as a compelling technique for the fabrication of complex metallic components through an additive manufacturing approach. This study investigates the effect of intrinsic heat treatment (IHT) on the microstructure and mechanical properties of Al-Cu alloy during the WADED process. The inherent cyclic reheating during deposition enables in situ grain growth, partial aging, and non-uniform precipitation of intermetallic compounds. We observed a significant increase in average grain size from 26.1 μm to 40.1 μm following IHT, which correlated with a decline in both micro-hardness and tensile strength of the as-deposited alloy. To counteract these effects, a subsequent solution treatment followed by a 16-hour aging period was employed, effectively mitigating the adverse microstructural changes and leading to marked improvements in the mechanical properties of the alloy. This research highlights the potential of leveraging the IHT mechanism to optimize microstructural and mechanical characteristics in WADED Al-Cu alloy, paving the way for enhanced performance in practical applications.