Laser polishing of hard and brittle materials: A review

Hard and brittle materials (HBMs) are widely employed across various industries due to their exceptional mechanical properties. However, their inherently high hardness and brittleness pose significant challenges in machining, often resulting in surface and subsurface damage during production, particularly in mechanical operations. Such damage degrades surface roughness and compromises overall surface integrity. Laser polishing has emerged as a promising solution to mitigate fabrication-induced defects and enhance both surface quality and accuracy. This review examines recent advances in laser polishing of HBMs, focusing on the principles of laser polishing mechanism, heat transfer and fluid flow including analytical and numerical modelling. Also, experimental studies to enhance surface integrity including surface roughness, morphology, microstructure, and hardness are discussed. The paper concludes by outlining potential future directions and research prospects aimed at overcoming current limitations and further advancing laser polishing techniques for HBMs.