2018 Volume 59 Issue 9 Pages 1513-1519
Friction stir processing (FSP) was applied to modify the microstructures of Al–36Si composite. FSP resulted in a significant breakup of coarse primary Si particles in the processed zone (PZ), and the size and aspect ratio of the Si particles decreased with increasing the number of FSP passes. The refinement and homogenization of Si particles during FSP can lead to an improvement in both strength and ductility, though FSP caused softening behavior in the PZ due to thermal cycle during the processing. Post-FSP aging treatment partially recovered the microhardness in the PZ of FSP samples, resulting in the enhanced strength and ductility. Furthermore, post-FSP T6 treatment resulted in a considerable enhancement in the microhardness in the PZ which could reach up to a similar level of the base material (BM). Therefore, the tensile strength was significantly improved to 381 MPa, which was much higher than that of the BM (187 MPa). This study provides an effective method of improving the mechanical properties of the Al–36Si composite.