LAUSR

The issue of weld solidification cracking in fusion welding of highly alloyed aerospace aluminum alloys is eliminated in friction stir welding (FSW) because the base materials do not melt during welding. However, in FSW, the weld joint quality characteristics are found with highly sensitive for the variation of process variables. Therefore, this investigation deals with the analysis of the significance of FSW processing conditions, construction of stochastic tensile failure probability models for dissimilar AA6061-T6 with AA7075-T6 aluminum alloy friction stir welded joints, and postulation of their statistical predictive models. The experimental results have shown an effective mixing at the interface of both base alloys attributed to efficient bonding and resulted in the mechanical properties with the weld joints. A lowest tensile strength was achieved for the weld joint produced by the straight cylindrical profiled tool pin, which is 24.51% lower than the UTS of AA6061-T6 unwelded alloy while 59.09% lower than the AA7075-T6 unwelded alloy. The survival probability of the weld joints fabricated at 30 mm/min is 92% for 260 MPa applied stress, but the weld joints fabricated at 20 and 40 mm/min are 70 and 40%, respectively. For 50% reliability of the weld joint, the maximum allowable stress values suggested are 270, 288, and 255 MPa for processed at of 20, 30, and 40 mm/min welding speeds, respectively. The application stresses beyond 290 MPa, and the survival probability of the weld joints fabricated at 40 mm/min is zero. Empirical models postulated for tensile strength, ductility, and microhardness were fund with a reasonable agreement with their experimental measurements statistically. The derived reliability and empirical models can be used to estimate the reliability of the welded joints and predict their mechanical properties to estimate and enhance the functional performance of the welded structures in automobile and aerospace applications.