Surface and subsurface response to the in-situ laser assistance in ultra-precision diamond turning of SiCp/Al composites.

Abstract

This study focuses on the application of in-situ laser-assisted single-point diamond turning (ILAT) on SiCp/Al metal matrix composites (MMCs), renowned for their exceptional mechanical properties and difficult-to-cut nature. The surface and subsurface response to the in-situ laser assistance under a small uncut chip thickness (UCT) is investigated. The results demonstrate that appropriate laser energy can reduce subsurface crystal defects while maintaining surface quality during machining. As the laser power increases, the surface damage pattern shifts from cut-through to fracture, eventually leading to severe matrix deformation. Slight compressive stress is observed on the Al phase of surfaces machined with either conventional single-point diamond turning (SPDT) or ILAT. Al crystals near the machined surface and SiC particles in the SPDT sample exhibit a notable accumulation of dislocations. Laser assistance is beneficial for mitigating dislocations and improving the crystalline integrity of Al grains, while Al grains close to the machined surface in both SPDT and ILAT samples present comparable amounts of stacking faults. The findings enhance the understanding of surface and subsurface generation of SiCp/Al composites in ILAT, providing a reference for the application of ILAT on other MMCs.