微观结构对板条马氏体启裂和裂纹稳态扩展的影响

The Effect of Microstructure on Crack Initiation and Steady State Propagation of Lath Martensite

研究了具有典型板条马氏体组织的低联合金结构钢启裂和裂纹早期扩展阻力与微观组织结构、断裂过程中消耗功之间关系。结果表明：板条马氏体微观组织结构决定裂纹尖端塑性约束程度；微观组织结构特征不同，裂纹尖端塑性约束程度不同，启裂过程和裂纹早期稳态扩展过程中消耗的弹性能和塑性功不同，导致材料抵抗裂纹稳态扩展的阻力有较大差异。

The relationship among crack initiation and resistance of steady state propagation, microstructure, deformation work absoTbed in the fracture process for lath martensite was investigated. The results shown that the plasticconstrain ahead of the crack tip is mainly determined by microstructure of lath martonsite. This influence the deformation work,such in elastic energy and plastic work,absorbed in the crack initiation process and steady state propagationprocess. So the resistance of steady state propagation of crack is difference.