Optimization of process parameters for improvement of joint strength of dissimilar aluminum alloys by friction stir welding with an activated flux of titanium diboride

The friction stir welding technique is employed for similar or dissimilar aluminum alloys without edges melting. The joints suffer from inferior strength due to the formation of intermetallic compounds; improvement in those properties is possible by adding filler materials. In the present investigation, the reinforcement of TiB₂ particles was applied as filler material for joining AA2014 and AA6082. Mechanical properties and microstructural analysis were carried out to evaluate the influence of TiB₂ particles. The process parameters were optimized for better joint strength. It was found that adding TiB₂ results in refined grains and a pinning effect, improving the tensile strength and hardness values. An ultimate tensile strength of 180.12 MPa was obtained at an optimal combination of rotational speed of 1200 rpm, a feed rate of 20 mm/min, and a tool penetration depth of 0.1 mm. The hardness of the joint was 130.2 HV0.1, which is 4% higher than AA2014. There was a marginal improvement in impact strength, which could be due to the presence of voids.