Effect of multi-pass friction stir processing and SiC nanoparticles on microstructure and mechanical properties of AA6082-T6

In this work, aluminum matrix composite (AMC) was successfully fabricated by multi-pass friction stir processing (MPFSP) with nanoparticles SiC. A constant rotational tool speed of 1350, feed rate of 65 mm/min, tilt angle of 2° was used to enhance the microstructure and mechanical properties of multi-pass FSP/SiC of AA6082-T6. It can be observed that Nanoparticles SiC were fragmented totally and uniformly distributed in fifth pass FSP. Agglomeration of SiC decreases with increases in the number of passes. The ultimate tensile strength (UTS) of base metal AA6082 exhibited 215.54 MPa, and % strain of 24.91. After implementing multi-pass FSP with nanoparticles of SiC on the AA6082, the UTS was enhanced simultaneously as the FSP pass increases. The UTS of 1st pass, 2nd pass, 3rd pass, 4th pass, and 5th pass was observed as 223.61 MPa, 238.37 MPa, 255.63 MPa, 281.79 MPa and 296.86 MPa, respectively caused by strain-free fine grains during dynamic recrystallization (DRX) mechanism. In contrast, Vickers's hardness value along the centerline (stir zone) was observed as 89, 101, 119, 125, 133 HV with 1st pass, 2nd pass, 3rd pass, 4th pass, and 5th pass respectively.