Laser Surface Modification of Wire-Electric Discharge Machined Graphene Nanoparticle Reinforced SiC Composites

Abstract

Electrical discharge machining of conducting ceramics is often associated with high roughness and porosity, which hinders their application. This porosity-laden surface morphology necessitates a postprocessing technique to reduce the severity of the surface defects. Hence, this study focuses on the utilization of a nanosecond pulsed laser as a surface modification tool to minimize the debris and pores formed on the surface after the wire-electrical discharge machining process. This paper presents a study on the influence of laser parameters, viz., power, number of scans, scanning speed, and pulse repetition rate on the overall surface characteristics. The concentration of surface debris and pores were observed to significantly decrease with laser surface modification (LSM). The improvement in the surface characteristics after laser processing with low fluence was mainly attributed to melting, vaporization, and subsequent flow of molten material, which led to filling of the surface pores. This resulted in a more even surface postlaser surface modification. The surface roughness was observed to decrease by ∼49% after the laser processing at lower values of laser power, number of scans, and scanning speed and at higher values of pulse repetition rate. Furthermore, spatial, hybrid, and functional volume characteristics were observed to improve postlaser modification. However, at higher laser fluence, the processed surfaces were observed to get further worsened with the formation of deep ridges.