(哈爾濱工業(yè)大學(xué)材料科學(xué)與工程學(xué)院，哈爾濱 150001)
摘 要: 利用掃描電鏡觀察了含30%TiC顆粒(體積分?jǐn)?shù))的鎢基復(fù)合材料在室溫和高溫的微觀斷裂過程，討論了裂紋萌生、擴展條件及其影響因素。室溫下的斷裂過程受控于裂紋萌生階段，相應(yīng)的應(yīng)力-撓度曲線表現(xiàn)為線性，TiC顆粒和W基體在微觀上都呈現(xiàn)脆性斷裂。高溫下的斷裂則存在一個亞穩(wěn)態(tài)的初始裂紋長大和合并過程，使應(yīng)力-撓度曲線呈現(xiàn)出非線性，在微觀上TiC顆粒呈現(xiàn)脆性斷裂，W基體呈現(xiàn)韌性撕裂。同時也指出了復(fù)合材料在室溫和高溫下的強化機制。
關(guān)鍵字: 鎢基復(fù)合材料 TiC顆粒 斷裂行為 強化機制
（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
