Shear punch and tribological characteristics of the in-situ friction stir processed Al-Al3Ni composites

Al-Al 3 Ni in-situ composites were formed on cold-worked aluminum by adding nickel powders in the pre-fabricated grooves and applying 2, 4, and 6 passes of friction stir processing (FSP). The treated specimens were characterized using SEM equipped with EDS, XRD, and microhardness tests. Shear punch tests (SPT) were also conducted at a loading speed of 0.25 mm/min. FSP of the as-received material reduced the hardness, yield shear strength (YSS), and ultimate shear strength (USS). Nevertheless, the hardness values of the fabricated composites were higher than those of the as-received material. Moreover, increasing the number of FSP passes further improved the composites' hardness, YSS, and USS. The composites produced by 6 passes of FSP showed a hardness increase of approximately 65% and a USS of about 75% higher compared to that of the as-received aluminum. The tribological behaviors of the composites and as-received material were also examined against AISI 52100 steel disc (∼850 HV). The presence of Al 3 Ni particles resulted in a reduced wear rate but increased the friction coefficient. After 500 m of sliding, the wear rate of the as-received aluminum was about 15.5 times higher than those of the 4 and 6-pass fabricated composites.