Process optimization and mechanical property of friction stir welded AA6061–SiC/TiB₂ composite

Abstract This study investigates the fabrication, mechanical properties, and friction stir welding (FSW) characteristics of AA6061 hybrid composites reinforced with varying amounts of SiC (10%, 7%, 4%) and TiB 2 (5%, 8%, 11%). The stir-casting technique facilitated a uniform dispersion of reinforcements within the matrix. Mechanical testing revealed that samples with higher TiB 2 content exhibited enhanced tensile strength and microhardness. In contrast, samples with greater SiC content demonstrated superior compressive strength, consistent with the inherent ceramic properties of SiC. Microstructural analysis confirmed the homogeneous distribution of reinforcements throughout the matrix. FSW was employed to assess welding performance, with spindle speed, feed rate, and reinforcement content identified as key process variables. A peak tensile strength of 165 MPa was achieved at a spindle speed of 1100 rpm and a feed rate of 70 mm min −1 for the Al-10 wt% SiC-5 wt% TiB 2 composite, while the lowest tensile strength of 147 MPa was observed in the Al-4 wt% SiC-11 wt% TiB 2 composite. Microhardness values were higher on the advancing side of the weld zone, particularly at elevated spindle speeds. Tool wear analysis revealed both adhesive and abrasive wear mechanisms, influenced by the reinforcement particles, with significant flash formation on the retreating side. Optimization analysis predicted a tensile strength of 161.13 MPa and a microhardness of 107.83 HV in the weld zone. The combined desirability value of 0.75541 indicates promising results, suggesting substantial potential for tensile strength and microhardness improvement.