氢致Ⅰ型裂纹扩展的位错塞积群模型

本文利用位错理论和夹杂理论研究了Ⅰ型裂纹前方的位错塞积群和氢气团以及它们之间的交互作用，求得了塞积群的位借密度、应力集中系数和裂纹扩展速率。所得结果表明，氢气团促进裂纹尖端位猪源开动，即促进滞后塑性变形，提高塞积群的应力集中系数，引起材料脆化，促进微裂纹核形成。

Dislocation Pile-up Model about the Hydrogeninduced I-Type Crack Extension

The dislocation pile-up and the hydrogen atmosphere at the I-type crack tip as well as the in-teraction between them have been investigated using the dislocation theory and inclusion theory. The dislocation density and stress concentration coefficient and crack extension rate of pile-up were obtained. Theresults showed that the hydrogen atmosphere can accelerate the dislocation source at the crack tip to start,namely, promote the hysteresis plastic deformation taking place, and make the stress concentration coefficient of the pile-up increase, and hasten the formation of the microcrack nuclei and result in material embrittlement.