Abstract To address the limited understanding of the influence of different welding speeds on the performance of thin-walled 205C aluminum alloy components fabricated via CMT+P dual-pass forming, a single-variable comparative study was conducted within the speed range of 9.0–10.5 mm s −1 to establish the relations between welding speed and porosity, microstructure, and mechanical properties. Quantitative evaluations of microstructure and properties were performed using XRD, EBSD, TEM, microhardness testing, and transverse and longitudinal tensile specimens. The results indicated that the lowest porosity and optimal overall tensile performance were achieved at a welding speed of 10.0 mm s −1 . At this welding speed, the average transverse tensile strength and elongation reached 277.5 MPa and 13.75 %, respectively, while the corresponding longitudinal values were 262.5 MPa and 10.75 %. The maximum tensile strength of 278 MPa was achieved at 10.0 mm s −1 , and the average elongation was about 2.9 % higher than that at 9.0 mm s −1 . The average microhardness was measured at 73 HV, ranging from 67.8 to 77.1 HV. The microstructure predominantly consisted of fine equiaxed grains, with a grain boundary network dominated by high-angle grain boundaries. As the welding speed increased from 9.0 mm s −1 to 10.5 mm s −1 , the average grain size decreased from 51.73 μm to 34.80 μm. The mean KAM initially increased and then decreased, reaching its lowest value and most concentrated distribution at 10.5 mm s −1 . Although the tensile strength at 9.5 mm s −1 was slightly lower than that at 10.0 mm s −1 , the microhardness distribution was most uniform with the narrowest variation range. The macroscopic texture remains weak across all conditions, indicating a limited influence of welding speed on texture development. Within the investigated process window of 9.0–10.5 mm s −1 , this study provides experimental evidence and a practical reference for selecting welding speed in CMT+P WAAM of 205C aluminum alloy components.
Wang et al. (Thu,) studied this question.