This study examined cold metal transition (CMT) and arc oscillation effects on aluminum alloy additive manufacturing, addressing microstructure heterogeneity, anisotropy, and porosity. Comparative analysis of CMT, CMT + P (Plus), and CMT + O(Oscillation) revealed that CMT + O broadens the molten pool, enhances fluidity, reduces porosity to 0.42% (1.46% lower than non-oscillation), and promotes bubble escape. Microstructure analysis showed heterogeneous layers of equiaxed and columnar crystals. Arc oscillation improved homogeneity via secondary nucleation, reducing texture strength from 5.31 to 3.32 and weakening anisotropy. Mechanical tests indicated CMT + O achieved 77.9 HV _0.2 hardness, 7.6% higher tensile strength (216.7 MPa), and 26.4% increased elongation (13.4%), attributed to refined microstructure and ductile fracture characteristics.

The macrostructure, microstructure and wear performance of Al cladding fabricated by cold metal transfer (CMT) technique were investigated. The overlaps were formed on both sides of Al cladding using CMT technique with direct current mode. The weld depth and contact angle increased, and the overlap length reduced with an increase of heat input, which can be realized by increasing wire feed speed (WFS) or arc length correction (ALC). The grain size and thickness of heat affected zone increased with an increase of heat input, which resulted from increasing WFS or ALC. Due to the increase of average grain size, the hardness value of the clad Al alloy reduced with the increase of ALC. Besides, wear rate increases with an increase of ALC under the scope of load between 80 and 120 N and time between 10 and 20 min. The grooves are clearer at the wear surfaces with an increase of ALC at the wear surface.