Synergistic effects of optimizing stir casting and friction stir welding for WC and Al2O3 based nano-particulates reinforced AA2014 and AA6061 alloys: Mechanical, weldability, corrosion, and microstructural morphological insights

This paper aims to investigate metallurgical changes and mechanical properties of stir casted AA2014 and AA6061 metal matrix composites and their as-weld condition developed with FSW technique. The composites, AA2014 and AA6061were developed by adding 5% WC and 5% Al 2 O 3 using stir casting process to study the impact of nano-particulates on material's properties. The stir casting developed samples were joined using FSW process using square tool to investigate the weldability, weld strength quality, wear and corrosion behavior. In addition, the microstructural changes due to the nano-particulates and welding process at the weld zone were reported. The tensile strength and micro-hardness were evaluated by applying uni-axial loads and indentation loads on the surface, respectively. Wear rate and corrosion resistance of FSW dissimilar joint were measured by using pin-on-disc and cyclic sweep tests, respectively. The UTS of AA2014 and AA6061 stir casted composites was observed as 155 and 184 MPa respectively whereas the UTS of dissimilar welded AA2014 and AA6061 composites was observed as 156 MPa with std. deviation of ±2. The average micro-hardness number is observed as 116 HV for AA2014 and 46 HV for AA6061 stir casted samples. The hardness number was increased in HAZ and TMAZ of AA2014 side in FSW joint as compared to stir casted composite. The FSW welded sample showed excellent resistance to environmental degradation with a low corrosion rate of 0.0131563 mm/year and excellent wear resistance, as evidenced by a less wear depth of 20 μm. Microstructures revealed that the nugget zone is exhibited with uniform, defect-free joints with evenly distributed reinforcement phases. The findings highlight the material's suitability for lightweight, durable components in aerospace, automotive, and marine industries.