Effect of P-MIG and CMT on microstructure and properties of 6082-T6 joints

Abstract

This paper focuses on pulse metal inert gas welding (P-MIG) and cold metal transfer (CMT) of 6082-T6 aluminium alloy. The microstructure and properties of joints were analysed and the phase transformation of the welding zones (WZ) was calculated using JMatPro. The results showed that CMT joints are better than P-MIG joints in tensile strength and hardness. The main reason is that the average grain size and the second phase size of CMT joints are smaller than those of P-MIG joints. Moreover, the larger number of large-angle grain boundaries (LAGB), diffusely distributed Al3Mg2 and Al6Mn phases in CMT WZ, as well as a small amount of distributed Al3Zr, are beneficial to the joints properties too.