<p>High-performance ceramic material composites (CMCs) have excellent applications in aerospace industries. However, the machining of the CMSs is challenging due to the inherent properties such as high hardness, heterogeneous structure, and brittleness. Understanding the machinability, ablation mechanism, and the magnitude of the damage is essential to control the machining quality. The study investigates the characteristics of laser process parameters on the machinability of the Al<sub>2</sub>O<sub>3</sub>/Al<sub>2</sub>O<sub>3</sub> CMCs in the femtosecond regime. The laser-machined slots were subjected to geometrical analysis, surface roughness measurements, and material removal rates with respect to the process parameters. The laser-machined surface structures and the microstructures of the cross-sections were analysed by scanning electron microscope. The study reveals that high laser power favours the maximum material removal rate irrespective of the scan rates. The peak material removal rate of 2.36 mm<sup>3</sup>/min was achieved at the power level of 14.23 W. High laser power and slow scan rates produced a smooth machined surface of the slots due to the melting and resolidification of the surface. Some microcracks were observed at the bottom of the laser-machined slots. The microcracks were more prominent in the transverse direction compared to the longitudinal direction. The formation of microcracks is due to the expansion and shrinkage caused during the laser machining process. The elemental analysis of the slots reveals a thick oxide layer at the bottom of the slots, and the thickness of the oxide layer is a function of laser power and scan rates.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Precision machining of alumina-reinforced ceramic matrix composites by femtosecond laser

  • Jagdheesh Radhakrishnan,
  • Rhys Scott,
  • Sundar Marimuthu

摘要

High-performance ceramic material composites (CMCs) have excellent applications in aerospace industries. However, the machining of the CMSs is challenging due to the inherent properties such as high hardness, heterogeneous structure, and brittleness. Understanding the machinability, ablation mechanism, and the magnitude of the damage is essential to control the machining quality. The study investigates the characteristics of laser process parameters on the machinability of the Al2O3/Al2O3 CMCs in the femtosecond regime. The laser-machined slots were subjected to geometrical analysis, surface roughness measurements, and material removal rates with respect to the process parameters. The laser-machined surface structures and the microstructures of the cross-sections were analysed by scanning electron microscope. The study reveals that high laser power favours the maximum material removal rate irrespective of the scan rates. The peak material removal rate of 2.36 mm3/min was achieved at the power level of 14.23 W. High laser power and slow scan rates produced a smooth machined surface of the slots due to the melting and resolidification of the surface. Some microcracks were observed at the bottom of the laser-machined slots. The microcracks were more prominent in the transverse direction compared to the longitudinal direction. The formation of microcracks is due to the expansion and shrinkage caused during the laser machining process. The elemental analysis of the slots reveals a thick oxide layer at the bottom of the slots, and the thickness of the oxide layer is a function of laser power and scan rates.