Effect of SiC addition on the high-frequent cyclic ablation of C/C-AlSi composites.

Components such as pistons in high-power diesel engines and barrels of rapid-fire weapons are often exposed to cyclic impacted high-temperature combustion. C/C-AlSi composites exhibit exceptional mechanical property, good particle erosion resistance and remarkable short-term anti-ablation ability. However, the cyclic ablation of the composite was primarily dominated by thermal stress damage between the alloy matrix and the carbon skeleton. In this study, SiC was utilized to mitigate such failures. C/C-SiC-AlSi composites were prepared by slurry impregnation method, and C/C-AlSi composites were also carried out for parallel comparison. The results indicate that the SiC and resin-carbon hybrids in the prepared composites are evenly distributed between the carbon fibers and the aluminium alloy matrix. Furthermore, the C/C-SiC-AlSi composites exhibit a greater density, a higher coefficient of thermal expansion and a better resistance to high frequent cyclic ablation. The mass ablation rate and linear ablation rate of the C/C-AlSi composites and the C/C-SiC-AlSi composites gradually decrease with increasing ablation time. When the ablation time is 200 s, the mass ablation rates of C/C-AlSi composite and C/C-SiC-AlSi composite are 0.20 mg/s and 0.12 mg/s, respectively. Compared to the two composites, the mass ablation rate of C/C-SiC-AlSi composite is reduced by approximately 40 %. The ablated morphologies indicated that the addition of SiC particles alleviated the thermal stress on the carbon skeleton and the alloy matrix, resulting in reduced mechanical damage. [ABSTRACT FROM AUTHOR]