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总览 评价 索涛 , 李玉龙 * , 杨建波 ( 西北工大学航空学院,西安 710072; ) 摘要: 利用高温电子万能实验机及具有高温同步自组装功能的Hopkinson压杆对二维碳纤维增韧的陶瓷基碳化硅复合材料进行了应变率为10-4 至1 103 1/s,温度由室温至1273K下的单
索涛, 李玉龙*, 杨建波
(
西北工大学航空学院,西安 710072; )
摘要:
利用高温电子万能实验机及具有高温同步自组装功能的Hopkinson压杆对二维碳纤维增韧的陶瓷基碳化硅复合材料进行了应变率为10-4 至1 103 1/s,温度由室温至1273K下的单轴压缩力学性能测试。实验结果表明二维C/SiC复合材料破坏时并未表现出典型的脆性破坏,而是在应力达到破坏强度时出现了显著的应变软化,在经历了较大的变形后才最终破坏。同时材料还表现出良好的高温承载能力及一定的温度和应变率依赖性。与准静态下室温压缩时相比,材料在1273K时的抗压强度的降低程度不超过30%。随着温度的升高,复合材料的抗压强度呈降低的趋势,但其抗压强度对应变率的敏感性随着温度的升高而增大。由于高温下试样表面SiC抗氧化涂层被氧化的原因,C/SiC复合材料抗压强度对应变率的敏感性在温度为1073K时显著增大。
关键词:
固体力学;C/SiC复合材料;高温;高应变率;抗压强度
Suo Tao, Li Yulong*, Yang Jianbo
(
School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072; )
Abstract:
Mechanical behavior of a kind of 2D C/SiC composites was investigated at temperatures ranging from room temperature (293K) to 1273K under quasi-static and dynamic uniaxial compression by using an electronic universal testing machine and the split Hopkinson pressure bar (SHPB). The experimental results show that the composite has excellent high temperature mechanical properties at the tested temperature range. The compressive strength of the composites decreases no more than 30% at 1273K under quasi-static compression if compared with that at room temperature. Catastrophic brittle failure is not observed for the specimens tested at different strain rates. With the increase of experimental temperature, although the compressive strength of the 2D C/SiC composites decreases, the dependence of compressive strength on strain rate increases. At the temperatures above 1073K, the sensitivity factor of compressive strength on strain rate increases remarkably. It is proposed that the sharp increase in dependence of compressive strength on strain rate is due to the oxidation of SiC layer on the surface of specimens.
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