WC颗粒增强钢基复合材料热疲劳裂纹扩展方式与机理研究  

Research on the Crack Propagation Way and Mechanism of Thermal Fatigue for WC Particles Reinforced Steel Matrix Composites

作　　者：张宁[1] 董妍 倪琪[1] 周凡哲 童亚星 ZHANG Ning, DONG Yan, NI Qi, ZHOU Fanzhe, TONG Yaxing(Xuzhou Engineering Technology Research Center of Green Solding and Special Jiont, Xuzhou University of Technology, Xuzhou 221018, China)

机构地区：[1]徐州工程学院徐州市绿色钎焊与特种连接工程技术研究中心,江苏徐州221018

出　　处：《铸造技术》2018年第10期2186-2189,共4页Foundry Technology

基　　金：江苏省高等学校自然科学研究重大项目(17KJA460010);徐州市科技计划社会发展项目(KC16SG281);徐州市重点研发计划项目(KC17043);徐州市工业科技重点研发项目(KC16GZ015);2017年江苏省"双创计划"科技副总类项目(2017066)

摘　　要：以复合电冶熔铸技术制备的WC颗粒增强钢基复合材料为研究对象,通过热震试验,研究热裂纹的扩展方式、途径和基本规律,并分析了热疲劳机理。结果表明,萌生热裂纹需要一定的孕育期,五至十次循环后,裂纹就会萌生在缺口根部倒角圆弧与两边的切点处。热疲劳裂纹的扩展方式分为通过碳化物和钢基体的分界面扩展、贯穿大颗粒WC和大块碳化物扩展、沿网状碳化物链扩展、穿越WC小颗粒聚集区扩展、穿过鱼骨状碳化物扩展和穿越钢基体扩展。热疲劳裂纹的扩展可分为弯曲扩展或分岔扩展,裂纹扩展前方的孔洞、微裂纹和热应力聚集共同作用导致了热疲劳裂纹的延伸。热疲劳裂纹扩展机理是增强颗粒、钢基体、组织缺陷和热应力的综合作用结果。The WC particle reinforced steel matrix composites prepared by composite electroslag melting and casting technology were studied. The propagation mode, way and basic law of thermal fatigue crack were investigated and the mechanism of thermal fatigue was analyzed. The results show that the initiation of crack has an incubation period, the crack will be formed at the root chamfer of the notch and the cut point on both sides after five to ten heat cycles. The expansion of thermal fatigue crack is divided into through the interface between carbide and steel matrix, the large WC particles and clumps of carbide, the net carbide chain, aggregation area of small WC particles, fishbone carbide, and steel matrix. The extension of thermal fatigue crack can be divided into curved extension or bifurcate expansion, which is formed under the joint action of holes, microcracks and thermal stress concentration in front of crack tip. The propagation mechanism of thermal fatigue crack for WC particulates reinforced steel matrix composites is a comprehensive result of reinforcing particles, steel matrix, microstructure defects and thermal stress.

关 键 词：WC颗粒增强钢基复合材料 热疲劳 裂纹扩展 

分 类 号：TB331[一般工业技术—材料科学与工程]