夹杂物特征参数对拉伸载荷下超高强度钢裂纹萌生与扩展的影响

采用扫描电镜原位观测的方法,动态跟踪观察拉伸载荷作用下航空发动机轴类超高强度钢MA250中不同形状和尺寸的TiN夹杂导致裂纹萌生与扩展的微观行为,从微观角度分析拉伸载荷作用下夹杂物的几何长轴与外加载荷方向成不同角度时裂纹的萌生方式.同时讨论TiN夹杂中第一条裂纹萌生所需的应力与夹杂物面积的关系.结果表明,夹杂物面积越大,第一条裂纹萌生所需的应力越小.

Influence of Characteristic Inclusion Parameters on Crack Initiation and Propagation in Ultra-High Strength Steel under Tensile Load

In-situ tensile tests with special designed SEM were conducted to trace the whole process of crack initiation and propagation induced by TiN inclusion in ultra-high strength steel MA250 which is widely used for aircraft engine shafts.Influence of shape and size of inclusion on crack initiation was studied,and the relationship of inclusion area and the initiation stress of the first crack in the inclusion under tensile load was discussed.The results show that the larger is the area of an inclusion,the smaller is the initiation stress of the first crack in the inclusion.