Investigation on material removal and damage suppression mechanism of Sip/Al composites with in-situ laser-assisted cutting

Abstract

The incorporation of reinforced particles significantly complicates the ultra-precision machining for optical mirrors on particle-reinforced metal matrix composites, exemplified by Sip/Al composites. In this research, in-situ laser-assisted cutting (LAC) was employed to enhance the machinability of Sip/Al composites. The material removal and damage suppression mechanisms were analyzed through surface morphology, cutting forces, residual stress, and chip morphology. Furthermore, the coupled effects of laser and cutting parameters on the particle deformation behavior and machining damage were investigated. Finally, process validation was carried out to prepare aspheric mirrors on Sip/Al composites using in-situ LAC. The findings indicated that in-situ LAC effectively improves the ductile machining capability of Si particles, reducing cutting forces by 38 % and suppressing particle fracture. The laser enhanced the plastic flowability of matrix and suppressed chip fracture. The matrix cladding induced by laser effectively fills microcracks, pits, and other defects. However, the protruding microstructures caused by excessive cladding limit further improvements in surface quality. Based on the optimized process parameters, in-situ LAC can achieve ultra-precision machining of aspheric mirrors on Sip/Al composites with surface roughness Sa below 14 nm. The research provides theoretical guidance for exploring technical measures to enhance the surface quality of Sip/Al composites.