HYDROGEN-FACILITAED DISLOCATION EMISSION,MOTION AND INITIATION OF HYDROGEN-INDUCED MICROCRACK IN RAIL STEEL
重轧钢中氢促进位错发射,运动以及氢致裂纹形核

A special deflection device for TEM has designed and used to study the dislocation configuration change before and after recharging hydrogen. The relations among hydrogenfated microcrack initiation, dislocation motion and dislocation free zone (DFZ) were also studied. The results showed that hydrogen can promote dislocation emission and motion. When the dislocation emission and motion develop to a critical condition, hydrogen-facilitated microcrack will initiate in DFZ or at the top of the ored. This process is similar to that during tensile testing in the air.