Ablation Mechanism of AlSiB-C/C Composites under an Oxy-Acetylene Torch

• Published in: Metals (Basel ) Vol. 13; no. 1; p. 160
• Main Authors: Han, Qiuchen, Chang, Lei, Sun, Zhaoqun, Sun, Jiaqi, Wei, Zengyan, Wang, Pingping, Xiu, Ziyang, Gou, Huasong, Kang, Pengchao, Wu, Gaohui
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.01.2023
• Subjects: Ablation; ablation resistance; Acetylene; AlSiB-C/C composites; Aluminum; Carbon fibers; Composite materials; Cooling; Dissipation; Graphite; Heat; heat dissipation; Investigations; Morphology; Oxide coatings; oxy-acetylene flame; reactive melt infiltration; Sealing; Silicon; Sweat cooling; Transpiration; Beijing China; China
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met13010160

In order to improve the ablation resistance of C/C composites, an AlSiB alloy (mass ratio of Al/Si/B = 2:4:1) was used as a dissipative agent to fill the pores of a C/C composites matrix by reactive melt infiltration to prepare AlSiB-C/C composites. The microstructure evolution and ablation behavior of the obtained AlSiB-C/C composites (mass ratio of Al/Si/B = 2:4:1) under oxy-acetylene flame were investigated by SEM after ablating for 25 s, 50 s, 100 s and 150 s. At the beginning of the ablation process, thermal chemical erosion played a leading part. By using the heat-absorption effect of sweating and the sealing protection effect of the oxide layer, AlSiB-C/C composites significantly reduced the ablation surface temperature, and the linear ablation rate was 4.04 μm/s. With the process of ablation, thermal mechanical erosion tended to dominate. The specimen surface could not form a continuous covering of oxide film to slow down the flame scour, resulting in non-uniform ablation and further expansion of the ablation pit. The self-transpiration cooling behavior and the self-sealing of the ablation products of the dissipative agent played an important role in reducing the extent of thermal chemical erosion and preventing matrix ablation.