IMPROVEMENT OF THE MECHANICAL PROPERTIES AND MICROSTRUCTURE OF AA3105/AZ31 WELD IN FSW PROCESS

In this paper, the mechanical properties and microstructure of AZ31 and AA3105 joints obtained from single-pass friction stir welding are investigated. The microstructure of the weld has been analyzed by optical and scanning electron microscopy (SEM) to investigate the tunnel and volumetric (wormhole) defects, as well as the distribution of intermetallic phases. Moreover, the effect of different parameters of deviation angle, rotating velocity, linear velocity, and pin diameter on the tensile strength and Young’s modulus of the weld has been investigated. It was observed that increasing the rotating velocity from 900[Formula: see text]rpm to 1000[Formula: see text]rpm led to an improvement of about 8% in the Young modulus, while weld strength improved by 10% at a rotating velocity of 1100[Formula: see text]rpm. The optimization results showed that the Young modulus and weld strength can be improved simultaneously at a linear velocity of 30[Formula: see text]mm/min, deviation angle of [Formula: see text], rotating velocity of 1100[Formula: see text]rpm and a pin diameter of 3[Formula: see text]mm. Under the optimal conditions of the parameters, the values of tensile strength and Young’s modulus are improved up to 144[Formula: see text]MPa and 39[Formula: see text]GPa, respectively.