The surface softening mechanism of AlN ceramic by laser treatment

Aluminum Nitride ceramic is an excellent material for heat dissipation in electronic applications. The precision machining of AlN ceramic is difficult due to its high hardness and brittleness. To improve the machinability of the ceramic material, a microsecond laser was applied to soften the surface of AlN ceramic in this work. To reveal the surface softening mechanism of the laser processing of AlN ceramic, the phase composition, microstructure, processing depth and hardness variation of laser -treated AlN ceramic surface were studied. The phase transition and surface morphology evolution during laser treatment were explained. It was found that Al and Al2O3 were formed on the surface after laser treatment. The surface hardness decreased from 14.3 GPa (base material) to 0.708 GPa. The revealed surface softening mechanism of laser treatment in this work is helpful for the optimization of the softening process and post -machining quality.