The T-joints of medium-thick 6082 Al-alloy plates created by dual pulsed gas metal arc welding (P-GMAW) and bilateral synchronous welding were investigated to improve weld quality using the adaptive deposition method, which calculates the minimum amount of deposition according to the welding condition, groove size, and cross-sectional area, effectively reducing the heat input and deformation of the welds on the basis of weld filling. The optimized linear energy with a wire feed speed (WFS) of 9.5 m/min can ensure a well-formed weld with a complete root fusion, and high-quality T-joint welds were obtained both in root openings of 0 mm and 1 mm. The biggest penetration was 4 mm, which was four times more than that of the result from a single torch welding process. When the distance between the two welding torches exceeded 20 mm, the molten pool was completely separated, and process pores were observed in the unfused root zone. Influenced by the thermal cycles in asymmetric welding, the hardness distribution changed: the width of the softer zone at the base plate with the fore arc was smaller than that zone with the rear arc. Furthermore, dual P-GMAW bilateral synchronous welding with an asymmetric heat source can further reduce the deformation of the welded joint by about 20% compared to that of symmetric welding.

This study addresses critical challenges in manufacturing GRCop-42 Cu alloy (Cu-4Cr-2Nb) components via laser-directed energy deposition (LDED). We systematically establish process–microstructure–property correlation for this alloy, demonstrating that laser power critically governs defect formation and mechanical performance. The alloy exhibited optimal microstructure and properties at a laser power of 2000 W, with a room temperature tensile strength of 319 ± 6.5 MPa and an elongation of 25.42 ± 1.9%. The tensile strength in the high-temperature tensile test at 600 °C was measured at 98 ± 3.1 MPa, with an elongation of 15.83 ± 1.5%. The comprehensive performance reaches the optimal value of the processing window. Through cross-scale characterization techniques, the differences in fracture mechanisms at different temperatures are clarified for the first time: at room temperature, a microporous aggregation-type ductile fracture is observed, with plastic deformation primarily dominated by dislocation slip; in a high-temperature environment, due to the weakening of grain boundary strength, the fracture mode shifts to intergranular fracture, and the deformation mechanism evolves into a synergistic effect of dislocation slip and twinning. The findings of this study not only provide valuable insights into optimizing the LDED process parameters for the GRCop-42 alloy but also shed light on the relationship between its microstructure and mechanical properties under different temperature conditions, offering a solid foundation for the further application of this alloy in complex aerospace components.