(哈尔滨工业大学材料科学与工程学院，哈尔滨 150001)
摘 要: 利用扫描电镜观察了含30%TiC颗粒(体积分数)的钨基复合材料在室温和高温的微观断裂过程，讨论了裂纹萌生、扩展条件及其影响因素。室温下的断裂过程受控于裂纹萌生阶段，相应的应力-挠度曲线表现为线性，TiC颗粒和W基体在微观上都呈现脆性断裂。高温下的断裂则存在一个亚稳态的初始裂纹长大和合并过程，使应力-挠度曲线呈现出非线性，在微观上TiC颗粒呈现脆性断裂，W基体呈现韧性撕裂。同时也指出了复合材料在室温和高温下的强化机制。
关键字: 钨基复合材料 TiC颗粒 断裂行为 强化机制
（School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China）
Abstract:A scanning electron microscope(SEM) was employed to investigate the microprocess of fracture at both room temperature and high temperature in tungsten matrix composites containing 30%(in volume) TiC particles. The condition of crack initiating, propagating and the effecting factors have been discussed. The fracture of the composites at room temperature, which was determined by the crack initiating, was brittle, and the corresponding stress-deflection curve was linear. SEM observation on the crack path and fracture surface revealed the brittle fracture of both TiC and W matrix. There was a growth and coalescence of the initial substable cracks in the fracture at high temperature, and the stress-deflection curves displayed nonlinear characteristics. The rupture of TiC was brittle and the failure of W matrix was a ductile bearing. The strengthening mechanisms at both room temperature and high temperature were proposed.
Key words: tungsten matrix composites; TiC particle; fracture behavior; strengthening mechanism
