Guan Tianru, Lu Le, Chen Zhaofeng, Yang Lixia
International Laboratory for Insulation and Energy Efficiency Materials, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China.
Materials (Basel). 2023 Aug 3;16(15):5445. doi: 10.3390/ma16155445.
Material used for aero-engine fan blade requires excellent mechanical properties at high temperature (300 °C). Continuous carbon-fiber-reinforced silicon carbide ceramic matrix composites (C/SiC) are necessary candidates in this field, possessing low density, high strength, high modulus, and excellent high-temperature resistance. However, during the preparation process of C/SiC, there were inevitably residual pores and defects inside, resulting in insufficient compressive strength and reliability. The vacuum pressure melting infiltration process was used to infiltrate low melting point and high wettability aluminum alloys into the porous C/SiC composite material prepared by the precursor impregnation cracking process, repairing the residual pore defects inside the body. The porosity of porous C/SiC decreased from 49.65% to 5.1% after aluminum alloy repair and strengthening. The mechanical properties of C/SiC-Al composite materials strengthened by aluminum alloy repair after heat treatment were studied. The tensile strength of the as-prepared C/SiC-Al was 166 ± 10 MPa, which were degraded by 13~22% after heat treatment. The nonlinear sections of stress-displacement curve of as-treated samples were shorter than that of as-prepared sample. The hardness of aluminum alloy matrix after 300 °C 1 h heat treatment was 58 Hv, which was not obviously reduced compared with the sample without heat treatment. The vacuum infiltration of aluminum alloy is expected to have guiding significance for repairing and strengthening internal defects in ceramic matrix composites.
航空发动机风扇叶片所用材料在高温（300°C）下需要具备优异的机械性能。连续碳纤维增强碳化硅陶瓷基复合材料（C/SiC）是该领域的理想候选材料，具有低密度、高强度、高模量以及出色的耐高温性能。然而，在C/SiC的制备过程中，内部不可避免地存在残余气孔和缺陷，导致抗压强度和可靠性不足。采用真空压力熔渗工艺，将低熔点、高润湿性的铝合金渗入先驱体浸渍裂解工艺制备的多孔C/SiC复合材料中，修复材料内部的残余气孔缺陷。铝合金修复强化后，多孔C/SiC的孔隙率从49.65%降至5.1%。研究了热处理后铝合金修复强化的C/SiC-Al复合材料的力学性能。制备态C/SiC-Al的抗拉强度为166±10MPa，热处理后下降了13%至22%。处理后样品应力-位移曲线的非线性部分比制备态样品的短。300°C 1 h热处理后铝合金基体的硬度为58 Hv，与未热处理的样品相比没有明显降低。铝合金的真空熔渗有望对陶瓷基复合材料内部缺陷的修复强化具有指导意义。
