12Cr2Mo1R钢的韧脆转变机理

Toughness-brittle transition mechanism of 12Cr2Mo1R steel

利用夏比冲击试验测定了12Cr2Mo1R钢的韧脆转变温度,并通过SEM、XRD、光学显微分析等方法对该钢在低温下的韧脆转变机理进行了探讨。结果表明,12Cr2Mo1R钢的韧脆转变温度(FATT50)约在-95℃左右,在低温环境下12Cr2Mo1R钢中的位错运动受到抑制,造成位错在碳化物前发生塞积,萌生微裂纹,最终在外力作用下发生穿晶脆性断裂,符合Stroh位错塞积理论。

Toughness-brittle transition temperature of 12Cr2Mol R steel was tested by Charpy impact tester, and the mechanism of toughnessbrittle transition at low temperature was studied by means of SEM, XRD and metallographic microscope. The results show that the toughnessbrittle transition temperature FATrs0 of the 12Cr2MolR steel is about -95 ℃. The dislocation motion of 12Cr2MolR steel is restricted at low temperature, so the dislocation pile-up formed in front of carbides and microcrack is initiated, at last the brittle fracture occurs under external force. This mechanism is accorded with Stroh dislocation pile-up theoretics.