Microstructure and Mechanical Properties of Dissimilar Aluminum Alloys AA5052-H32 and AA2219-T31 Welded Using Cold Metal Transfer Process

ABSTRACT Lightweight structures fabricated from dissimilar aluminum alloys in aerospace and marine industries involve a lot of welding. Aluminum alloys AA5052-H32 and AA2219-T31 were successfully welded with the low heat input welding technology, the cold metal transfer (CMT) process. Microstructures indicated the existence of finer equiaxed dendrites and strengthening precipitates in the weld metal (WM). The microliquefaction cracks were discontinuous and propagated along the grain boundaries and with the grains of α-Al matrix in the WM. The tensile properties of the dissimilar welded joint attained a joint efficiency of 70.1 % and fracture ended in ductile nature with dimples and microvoids. The heat affected zone was narrow and noticed a drop in the hardness at both the interfaces caused by a softening phenomenon, ending up with coarse precipitates having lower hardness.