Carbon fiber reinforced ZrC based ultra-high temperature ceramic matrix composite subjected to laser ablation: Ablation resistance, microstructure and damage mechanism

摘要

Ablation-resistant performance and damage mechanism of carbon fiber reinforced ZrC based ultra-high temperature ceramic matrix composite prepared via alloyed reactive melt infiltration were investigated using a laser ablation testing method under different laser power densities (LPD) and time periods. Ablation damage of the composite was obviously enhanced tested with increasing LPD and reduced with prolonging tested time. A fused ZrO2 protecting layer was in situ formed during ablation testing, significantly improving the composite's ablation-resistant performance. Ablated microstructures of the composites tested with different LPD were characterized and an ablation mechanism going through three distinct periods was proposed. In the first period, the testing temperature is low and ablation damage was thought to be mainly controlled by the oxidation of carbon, ZrC and Zr2Si phases. With the increase of testing temperatures, ablation damage became controlled by evaporating of ZrO2 and SiO2 formed in oxidizing stage. In the final period with the highest testing temperatures, ablation damage became synergistically dominated by repeatedly scouring away and new formation of the fused ZrO2 protecting layer.