Microstructure and ablation behaviour of a Cf/SiC-Al composite prepared by infiltrating Al alloy into Cf/SiC

To utilise the heat-absorption effect of sweating and sealing protection effect of the oxide layer, Al alloy was introduced into porous C-f/SiC composite using pressure-infiltration method. Microstructure, compositions, mechanical properties of the infiltrated composites were studied. The ablation properties, ablation surface morphology evolution and ablation mechanism of the C-f/SiC-Al composites were investigated for the first time. Results show that the bending strength of C-f/SiC-Al reached 349.8 MPa, which was 58.5% higher than the 220.7 MPa of C-f/SiC composite. Compared with C-f/SiC composites, linear ablation rates of C-f/SiC-Al composites decrease nearly by two orders of magnitude. It was also found that the transpiration cooling of the aluminum alloy in the composite was prior to the mechanical denudation of the C-f/SiC composite. The excellent anti-ablative properties were also attributed to self-sealing protection of ablation products, which played important roles in reducing the degree of thermochemical ablation and preventing matrix ablation. (C) 2021 Published by Elsevier B.V.