Short pulsed laser ablation of Z-A ceramic matrix composite under ancillary environments: A comparative study

Abstract

Z-A, as a ceramic matrix composite, holds complexity in machining compared to monolithic ceramic due to its fundamental structure, which creates a synergy of properties that depend on the reinforcing material and matrix. When it comes to machining this material, laser machining has garnered a significant role compared to any conventional practices. Despite its advantages, some challenges are associated with laser machining while processing thicker substrates, mainly heat accumulation and energy loss after certain passes. In order to overcome these challenges, a unique laser stepping-down milling process has been adopted in this study to process thicker Z-A under ancillary environments like ambient, liquid, and solid. The current study has also focused on examining the impact of various laser processing variables on the effectiveness of the current approach by scrutinizing the responses, such as ablation rate, shape distortion, heat accumulation effect, and hardness property of the Z-A. The results showed that to minimize the heat accumulation effect, low-temperature environments such as liquid and solid environments have proven their potentiality over ambient environment by compromising the ablation rate under similar laser processing variables. However, when comparing the crystal structure, surface morphology, and crack behavior, it has been found that the fundamental structure is restored in a solid environment, unlike in liquid and ambient environments. Additionally, no significant polymorphic transformation has been seen during the laser-induced sub-surface analysis in liquid and solid environments.