Yang Lixia, Wang Fei, Liao Jiahao, Chen Zhaofeng, Kou Zongde
College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, 29 Yudao St., Nanjing 210016, China.
Herbert Gleiter Institute of Nanoscience, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Nanomaterials (Basel). 2022 Sep 28;12(19):3406. doi: 10.3390/nano12193406.
The effects of an α-AlO nanoparticle filler in the SiC matrix on the mechanical properties and failure mechanism of the unidirectional, laminated carbon fiber-reinforced SiC composites were investigated in this work. First, α-AlO nanoparticles were added to the carbon fiber bundles using a slurry impregnation method, and then the C/SiC composite with an α-AlO nanoparticle filler (C/SiC-AlO) was fabricated using a precursor infiltration and pyrolysis method. The microstructure of the C/SiC-AlO composite showed chemical compatibility between the α-AlO and the pyrolysis SiC. The C/SiC-AlO composite with a low porosity of ~6.67% achieved a good flexural strength of 629.3 MPa and a good fracture toughness of 25.2 MPa·m. The interlaminar shear strength of the C/SiC-AlO composite was 11.7 MPa. The SiC-AlO matrix also presented a considerable Young's modulus of 138.2 ± 8.66 GPa and hardness of 10.3 ± 1.03 GPa. Further analysis indicated that the good mechanical properties with the addition of an α-AlO3 filler were not only related to the dense matrix and the improvement of the mechanical properties of the matrix. They also originated from the thermal residual compressive stress in the SiC matrix close to the α-AlO nanoparticles caused by the thermal expansion mismatch, which could reflect and close the cracks in the matrix. The findings of this study provide more methods for designing new composites exhibiting a good performance.
在本研究中，研究了碳化硅基体中α - 氧化铝纳米颗粒填料对单向层状碳纤维增强碳化硅复合材料力学性能和失效机制的影响。首先，采用浆料浸渍法将α - 氧化铝纳米颗粒添加到碳纤维束中，然后使用先驱体浸渍热解法制备了含有α - 氧化铝纳米颗粒填料的C/SiC复合材料（C/SiC - AlO）。C/SiC - AlO复合材料的微观结构表明α - 氧化铝与热解碳化硅之间具有化学相容性。孔隙率约为6.67%的C/SiC - AlO复合材料具有629.3 MPa的良好弯曲强度和25.2 MPa·m的良好断裂韧性。C/SiC - AlO复合材料的层间剪切强度为11.7 MPa。SiC - AlO基体还具有相当高的杨氏模量，为138.2 ± 8.66 GPa，硬度为10.3 ± 1.03 GPa。进一步分析表明，添加α - 氧化铝填料后良好的力学性能不仅与致密的基体以及基体力学性能的改善有关。它们还源于热膨胀失配导致的靠近α - 氧化铝纳米颗粒的碳化硅基体中的热残余压应力，该应力可反射并闭合基体中的裂纹。本研究结果为设计具有良好性能的新型复合材料提供了更多方法。
