Wire-arc additive manufacturing of high-strength Al-Cu alloy via synergistic strengthening of Cd microalloying and TiC nanoparticle

The growing demand for efficiency manufacturing of large-scale complex structures with high performance has driven increased interest in wire arc additive manufacturing (WAAM). Al-Cu alloys, known for their excellent specific strength, are widely used in lightweight applications. However, the fabrication of Al-Cu alloy structures via WAAM often results in heterogeneous microstructures and porosity defects, which impairs mechanical properties. In this study, nanoscale TiC particles and Cd microalloying are introduced into Al-Cu alloy using the dual-wires WAAM method. The effects of TiC particles and Cd microalloying on microstructural evolution and mechanical properties of WAAM Al-Cu alloy are systematically investigated. The obtained results demonstrate that multiphase synergistically strengthened Al-Cu alloy exhibits a microstructure with fine equiaxed grains and significant suppression of porosity defects. The optimized heat treatment promotes the formation of high-density nanoscale θ′-Al₂Cu precipitates. The TiC/AlCuCd alloy in the vertical and horizontal directions showed an increase in YS, UTS, EL by 22.26 %, 25.61 %, 90.57 % and 24.32 %, 21.61 %, 85.16 %, respectively, compared to the AlCu alloy. The synergistic enhancement of strength and plasticity is achieved.