Enhanced strategies for suppressing hole surface damage in ceramic matrix composites during abrasive waterjet machining

Abstract

Hole surface damage severely impacts the overall performance of ceramic matrix composite components in the aerospace field. To reduce damage in ceramic matrix composites during abrasive waterjet hole-making, the present study proposes two surface damage suppression strategies: pre-drilled holes and avoiding damage-prone areas. Research results indicate that a pre-drilled hole allowance (T) of 0.1 mm (i.e. diameter of pre-drilled hole (D _p ) = 1.9 mm) can effectively suppress 27.7% of the damage, demonstrating the most significant damage reduction effect. Additionally, within the range of T between 0 and 0.2 mm, the use of the pre-drilled hole strategy consistently results in lower processing damage compared to not using any measures. When the allowance is set to 0 mm, 0.1 mm, or 0.4 mm, both tearing damage and peripheral composite damage are the dominant. In contrast, at allowances of 0.2 mm, 0.6 mm, 0.8 mm, or 1.0 mm, only peripheral composite damage remains predominant. The study reveals three main mechanisms of the pre-drilled hole strategy for damage suppression: reducing the energy required for final processing, facilitating the smooth expulsion of high-pressure water and abrasives, and decreasing impact force. The paper also clarifies the influence of material structure on surface damage during abrasive waterjet hole-making of C _f /SiC composites, recommending that hole-making positions avoid cutting through the ends of fiber bundles and stay away from or completely remove pure matrix areas. The findings provide a solid theoretical basis for low-damage abrasive waterjet hole-making of ceramic matrix composites.