Effect of cold metal transfer mode and arc oscillation on the microstructure and properties of additive-manufactured 2319 aluminum alloy

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.