示波冲击试验中裂纹生长与扩展机理研究

Crack Growth and Propagation Mechanisms of Impact Crack in the Instrumented Impact Test

通过示波冲击试验、金相分析、扫描电镜分析等方法,对P92钢室温示波冲击试验时,自裂纹萌生至断裂的全过程进行了分析,研究了裂纹的萌芽、生长和扩展规律。结果表明,冲击试样的破断过程可描述为裂纹的萌芽、生长和扩展直至断裂三个阶段。裂纹萌芽和生长过程对应宏观冲击断口的启裂区,裂纹扩展过程对应宏观冲击断口的扩展区。裂纹的生长和扩展过程因剪切裂纹和颈缩裂纹的交替出现而呈现转折的"之"字形路径。

The crack initiation, growth and propagation of P92 steel in the instrumented impact test at room temperature were studied by optical microscope and scanning electron microscopy. The results show that the rupture process of P92 can be divided into crack initiation, growth and propagation. The crack initiation and growth are corresponded with the crack initiation region of the impact fracture. The crack propagation is corresponded with crack extention region of the impact fracture. The crack growth and propagation follow a zigzag path for the alternant occurrence of the shear crack and the necking crack.