Experimental analysis of mechanical properties of aluminium alloy weldments by friction welding process under cryogenic treatment

The present study explores the mechanical and metallurgical properties of friction-welded dissimilar aluminium joints, namely AA6061-T6 and AA7079-T6 which were investigated with the use of a process parameter such as frictional pressure, upset pressure, speed, burn-off length. The parameters are varied according to L9 orthogonal array with three levels. The samples are subjected to non-destructive test to identify the weld integrity without disturbing the component which ensures the weld metals for fitness-for-purpose. Mechanical and metallurgical properties such as tensile strength, hardness and micro structure with 100x and 500x were taken to validate the process. Shallow cryogenic treatment was conducted with different time periods (48 and 72h). There was no significant improvement rather than reduction in tensile strength for 48h, but for 72h, there was an increase in maximum tensile strength of 224MPa. The welded zone showed complete fusions with some inter metallic phases that are obtained.