Femtosecond laser modification of silicon carbide to improve the materials removal efficiency

Abstract

Femtosecond laser, one of the ultra-fast lasers, was used to irradiate 4H-SiC wafers to modify the morphology and mechanical properties of the surface. The modified surface could exhibit a surface feather of laser-induced periodic surface structure (LIPSS). To investigate the machinability of modified SiC surface, the mechanical properties of the modified surface was characterized by nanoindentation. The influence of laser processing parameters on the LIPSS structure and mechanical properties was also studied. And the mechanical properties such as hardness and elastic modulus of each surface were investigated. The results show that, within a certain range, with the increase of the scanning speed, the ripple period formed on the surface of SiC gradually increases; the surface hardness and elastic modulus of the modified layer are greatly reduced, and with the increase of the depth, the hardness gradually approached that of the unmodified SiC, and the hardness of the three modified surfaces also varied, but it does not change linearly with the increase of the ripple period.