Performance evaluation of 2.5D C/SiC composite by chemical micro fluid assisted laser induced plasma micro-drilling

• A chemical micro fluid assisted laser induced plasma micro-drilling method was proposed to improve taper and HAZ. • The mechanism of HF and NaOH micro fluid assisted laser processing was expounded. • The morphology and chemical composition of the micro holes with different processes were compared and analyzed. • The influence of different processes on the mechanical properties of specimens in high-temperature environments was studied. The exceptional mechanical properties and high-temperature resistance of 2.5D carbon fiber reinforced silicon carbide ceramic matrix composites (C/SiC) have demonstrated a wide range of potential applications in the field of aero engine turbine blades. In response to issues such as the appearance of a large heat-affected zone (HAZ) during laser-induced ablation (LIA) and the formation of oxides that cause significant taper in micro holes. This paper presents a chemical micro fluid assisted laser induced plasma micro-drilling method to improve taper and HAZ. The surface quality, thickness of the HAZ, taper, surface chemical composition, and mechanical properties of the micro holes processed by two varieties of micro fluid, NaOH and HF, were comprehensively analyzed. The findings indicate that the HF micro fluid assisted laser induced plasma micro-drilling procedure offers substantial benefits. In comparison to LIA, the HAZ’s thickness is reduced by 78.12%-80.46%, the taper is reduced by 45.71%-46.36%, the average tensile strength in high-temperature environments increased by 5.81%, and the equivalent strain distribution was also more uniform. The micro holes’ edges are regular, and the sidewall surface is smooth. This study provides a new method for 2.5D C/SiC micro hole processing and new ideas for improving the quality of laser processing.