WC-钢基复合材料断裂韧性与断口形貌特征

Fracture toughness and fractographic characteristics of WC steel matrix composite

采用单边切口梁法（ＳＥＮＢ）测试了１２种工艺状态的ＷＣ增强钢基复合材料的断裂韧性Ｋｃ，并用扫描电镜观察了其断口形貌．试验表明ＳＥＮＢ法对于ＷＣ－钢基合金的断裂韧性测试适用可行，数据稳定．研究发现数量众多（４０％左右）的硬质相对材料的断裂韧性起决定性作用，细化硬质相及加强硬质相－基体交互作用有利于材料断裂韧性的提高．断口的主要特征为ＷＣ解理。

By means of Single Edge Notch Beam (SENB) method, fracture toughnesses K c of the twelve kinds of processing conditions have been measured in WC steel matrix composite, and its fractographic patterns have also been observed using SEM. The results show that SENB method is suitable for the measurement of fracture toughness of the composite, with stable experimental data. The present research work has found that numerous hard phases (40%) play the predominant role to K c of the tested materials, and finer WC and enhancing the interaction between hard phase and steel matrix can improve fracture toughness of the material. The main characteristics of fractures of the WC steel matrix composite are the cleavage of WC, the quasi cleavage, the dispersed dimples and the dimple bands.