碳化钨钢结硬质合金表面热疲劳裂纹扩展的观察

本文借助于光学显微镜和扫描电镜，全面观察了在热应力的作用下，热疲劳裂纹在GJW50碳化钨钢结理质合金（未经锻造）表面扩展的全过程．观察结果表明，热疲劳扩展方式与硬质合金中的硬质相分布状态有关．小颗粒的硬质相聚集区与钢基体的界面是热疲劳裂纹的主要扩展地；热疲劳裂纹前沿已经开裂的大颗粒硬质相为热疲劳裂纹扩展的必经地．

OBSERVATION OF THE THERMAL FARIGUE CRACK PROPAGATION ON THE SURFACE OF STEEL BONDED CARBIDE

In this paper .all of the process of thermal fatigue crack propagation on the surface of steel bonded carbide(not forged) under the action of thermal stress has been observed by means of OM and SEM. The results show that the ways of the mal fatigue crack propagation have relation to hard phase distribution in the alloy. The boundary plane between the collection re-gion of small hard phases and steel basic phase is the main place of thermal fatigue crack propagation,and large cracked phas-es in front of a thermal fatigue crack is the certain place of the frack passing through