Experimental and numerical investigation on the ablation mechanism of Al2O3/Al2O3-CMCs under continuous-wave laser irradiation

Abstract

In this study, the ablation mechanism of Al2O3/Al2O3-CMCs under laser irradiation and the influence of laser parameters on the ablation efficiency were examined. The experimental results show that the diameters of the ablation centre and transition area are both positively correlated to the irradiation energy, and the irradiation power has a more prominent effect on the diameter of the ablation centre. The molten Al2O3 changes the reflection and transmission properties of laser beam, which results in an elliptical ablation pit. A macro-meso two-scale finite element (FE) model was established to simulate the laser ablation process progressively. The FE results show that the difference in thermal conductivity between the Al2O3 fibre and matrix induces a discrepancy in ablation at the mesoscale. The radius and depth of the ablation pit increase rapidly at the initial stage, then slowly increase with time. A good correlation between the experimental and numerical results was achieved.