The mechanism and machinability of laser-assisted machining zirconia ceramics

Laser-assisted machining (LAM) is regarded as a useful technique which can process ceramic materials without damage and efficiently. This work reported a study on the mechanism by which LAM technology can improve the machinability of zirconia ceramic. The absorptivity of zirconia ceramic to fiber laser energy was obtained through the combination of experiment and simulation. The temperature-dependent mechanical property of zirconia ceramic was studied by nanoindentation experiments. Meanwhile, scratch tests were used to investigate the plastic-brittle transition and damage mechanism under various high-temperature conditions. The results showed that the absorptivity of zirconia ceramic to fiber laser energy is 0.52. The hardness and elasticity modulus are decreasing as the temperature increases. The functions that relate them to temperature are fitted. Moreover, the increase in temperature can enhance the plastic-brittle transition depth of ceramic and suppress median cracks and chipping. Furthermore, the shape of the chips is changed from discontinuous lumpy chips to continuous coiled chips. These evidence and research can clearly explain the mechanism by which LAM technology can improve the machinability of zirconia ceramics. They can also provide guidance and theory for the industrialization of LAM technology.