SiC维纤增强钛基复合材料的疲劳裂纹扩展速率

Fatigue Crack Growth Rate in SiC Fiber Reinforced Titanium Matrix Composites

摘要:

用箔-纤维-箔法制备SiC纤维增强Ti-6Al-4V复合材料，研究复合材料在加载频率f=10 Hz、应力比R=0.1、最大应力σmax=300 MPa条件下的疲劳裂纹扩展速率 (da/dN)，并采用扫描电子显微镜对疲劳破坏断口进行观察和分析。结果显示，在该加载条件下，复合材料第Ⅱ阶段疲劳裂纹扩展速率符合高斯函数。断口观察表明，复合材料的基体在裂纹稳态扩展区出现明显的疲劳条带，复合材料的疲劳损伤可以分为纤维断裂、基体开裂和纤维/基体界面脱粘等多种形式

Abstract:

SiC fiber reinforced Ti-6Al-4V composites (TMCs) was prepared by the foil-fiber-foil method. The fatigue crack growth rate of the TMCs was investigated under the condition of f=10 Hz, R=0.1 and σmax =300 MPa, and the fracture surface of TMCs was observed by scanning electron microscopy (SEM). Results show that the crack growth rate at the stage Ⅱ of crack propagation is well consistent with Gaussian function. SEM observation indicates that distinct fatigue striations exist in the stable propagation area of the fatigue crack of the Ti-6Al-4V matrix. The failure modes of TMCs include fiber breakage, matrix cracking, fiber/matrix interfacial debonding, et al under the loading condition