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本文利用透射电子显微分析和x射线内应力测定等方法研究了低层错能面心立方合金表面喷丸强化后组织结构变化与疲劳行为之间的关系。着重观察和分析了疲劳过程中强化层内亚结构和内应力的变化情况。结果表明:层错能很低的面心立方合金(不锈钢和α黄铜)经喷丸强化后,表层中存在大量显微变形孪晶;由孪晶构成的栅栏薄层不仅能使表层残余压应力在疲劳应力作用下维持稳定,而且能有效地防止疲劳裂纹在外表面形核,因此,栅栏强化效应是面心立方合金疲劳强度提高的主要原因。
In this paper, the relationship between microstructure changes and fatigue behavior after shot peening of low-lying dislocation face-centered cemented carbides was investigated by means of transmission electron microscopy and X-ray internal stress measurement. Emphasis was placed on the observation and analysis of changes in the sub-structure and internal stress in the strengthening layer during fatigue. The results show that there is a large amount of micro-deformation twins in the surface layer after shot peening with face-centered cubic alloy (stainless steel and α-brass) with very low stacking fault level. The thin layer composed of twins can not only make the surface residual pressure The stress is stable under fatigue stress and can effectively prevent the fatigue crack from nucleating on the outer surface. Therefore, the reinforcement effect of the fence is the main reason for the increase of the fatigue strength of the face-centered cubic alloy.