二维C/SiC复合材料高温压缩力学行为研究

利用电子万能实验机和具有高温同步加载能力的分离式Hopkinson压杆装置,研究了二维碳纤维增韧的碳化硅复合材料在室温293 K~873 K时的准静态及动态压缩力学性能。实验结果表明:材料在高温下仍具有较高的承载能力,与室温时相比其动态抗压强度在873 K时仅下降了10%.分析认为,导致材料压缩强度随温度升高而下降的原因主要是由两个方面共同作用的结果:一是由于热膨胀系数不同引起的残余应力;二是氧化造成的承载能力下降,但氧化行为对该材料破坏强度的影响起到决定性作用。

Research on Mechanical Behavior of 2D C/SiC Composites at Elevated Temperature Under Uniaxial Compression

The quasi-static and dynamic compression mechanical behaviors of a kind of 2D C/SiC composite were investigated at temperatures ranging from 293 K to 873 K using the electronic universal testing machine and the split Hopkinson pressure bar. The experimental results show that the material still has a good carrying capacity even at the elevated temperature. The compressive strength of the composite at 873 K decreases by only 10% comparing with that at 293 K. The catastrophic brittle failures were not observed under both quasi-static and dynamic loading. It has been found through analysis that the decrease in carrying capacity of 2D C/SiC composite at elevated temperature is probably due to two reasons: the first one is the residual stress between the two phases because of the different coefficient of heat conductivity,and the second one is the effect of oxidation, which is considered as the more dominating reason of the softening behavior of 2D C/SiC composite at elevated temperatures.