Friction Stir Welding of Hybrid Recycled Metal Matrix Composites

In this work, conventional Friction Stir Welding (FSW) was used to investigate the weldability of recycled hybrid Aluminum Matrix Composites (AMCs). The novel composites were developed by squeeze stir casting process of scrap aluminum alloy wheels of cars as matrix and 4 wt.% of graphite, and 5 wt% of alumina as reinforcements. The casting parameters optimized from our previous work, such as squeeze pressure of 100 MPa, squeeze time of 45s, die preheating temperature of 250°C, and stirrer speed of 525 rpm, were used while casting the hybrid AMC rods. 4 mm plates were cut from each rod and subjected to an in-air friction stir welding process using a cylindrical tool of 16 mm diameter and 3 mm pin depth. Two-pass welding with a tool rotation of 1600 rpm and feed rates of 24 mm/min and 55 mm/min were used for FSW of samples. The welded section was cut out and subjected to mechanical tests such as tensile and Brinell hardness tests. It was observed that the samples welded at lower feed rates exhibited a higher tensile strength of 154 MPa and Brinell Hardness number of 61. The weldability of the recycled composites was successfully tested using FSW, a sustainable welding process. The work shows that hybrid recycled AMCs can be used for piping’s and structures prone to wear.