| 摘要: |
| 采用磁控溅射先驱丝法制备SiCf/TC17复合材料，在室温条件下对SiCf/TC17复合材料在拉弯载荷下的疲劳裂纹扩展行为进行了研究，探究不同应力比及疲劳载荷应力幅值、不同纤维体积分数、不同起始裂纹位置对SiCf/TC17复合材料的抗疲劳裂纹扩展性能的影响，并采用扫描电子显微镜对疲劳破坏断口进行观察和分析。结果表明，紧凑型（CT）疲劳裂纹扩展试样在疲劳裂纹扩展过程中易发生纵向劈裂现象，纤维体积分数的增加导致试样抗疲劳裂纹扩展能力增强，应力比越大裂纹偏转越急剧，纤维桥接效果越弱，载荷变化对纵向破坏模式几乎没有影响，起始裂纹位于包套区域时试样更容易发生纵向破坏。断口观察表明，纵向破坏模式下疲劳裂纹沿纤维/基体界面扩展，在裂纹扩展过程中复合材料发生纤维断裂、纤维拔出、纤维/基体界面脱粘、基体塑性变形等多种失效形式。 |
| 关键词: 钛基复合材料 SiC纤维 疲劳裂纹 纵向劈裂 |
| 基金项目:国家科技重大专项（HT-J20**-V1-00**-0121）。 |
|
| Tensile Flexural Fatigue Crack Propagation and Fracture Characteristics of SiCf/TC17 Composites |
|
Li Xinxin1, Zhou Wenlong1, Wang Minjuan2, Fu Xuesong1, Chen Guoqing1, Huang Hao*2
|
|
1. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024;2. Titanium Alloy Institute, Beijing Institute of Aeronautical Materials, Beijing 100095
|
| Abstract: |
| SiCf/TC17 composites were prepared by magnetron sputtering pioneer wire method, and the fatigue crack propagation behavior of SiCf/TC17 composites under tensile bending load was studied at room temperature, and the effects of different stress ratios, fatigue load stress amplitudes, different fiber volume fractions, and different initial crack locations on the fatigue crack propagation performance of SiCf/TC17 composites were explored, and the fatigue failure fractures were observed and analyzed by scanning electron microscopy. The results show that the compact (CT) fatigue crack propagation specimen is prone to longitudinal splitting during the fatigue crack propagation process, and the increase of fiber volume fraction leads to the enhancement of the anti-fatigue crack propagation ability of the specimen, the larger the stress ratio, the sharper the crack deflection, the weaker the fiber bridging effect, the load change has almost no effect on the longitudinal failure mode, and the specimen is more prone to longitudinal failure when the initial crack is located in the jacketed area. The fracture observation shows that the fatigue crack propagates along the fiber/matrix interface in the longitudinal failure mode, and the composite material undergoes various failure modes such as fiber breakage, fiber pull-out, fiber/matrix interface debonding, and matrix plastic deformation during the crack propagation process. |
| Key words: titanium matrix composites SiC fibers fatigue cracks longitudinal splitting |
