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利用冲击实验、拉伸实验、XRD和TEM对2种不同N含量的无Ni高N奥氏体不锈钢低温变形行为进行了研究.结果表明,高N奥氏体不锈钢在低温下发生明显的韧脆转变和加工硬化现象.在实验材料的Mn含量水平内,提高Mn含量能够改善高N奥氏体不锈钢的低温塑性和韧性,降低其韧脆转变温度.18Cr-12Mn-0.55N钢在低温拉伸变形时会发生形变诱导马氏体相变,但马氏体转变量很少,降低温度对马氏体转变量无明显影响.形变诱导马氏体能提高高N奥氏体不锈钢的加工硬化能力,但降低了钢的低温塑性和韧性.加工硬化能力和层错能随温度的降低而降低是Re-Cr-Mn高N奥氏体不锈钢在低温下发生脆断的主要原因.
The low temperature deformation behavior of two kinds of Ni-free, high-N austenitic stainless steels with different N contents was studied by impact test, tensile test, XRD and TEM.The results showed that the ductile brittleness of high N austenitic stainless steel occurred at low temperature Transformation and work hardening phenomenon.In the experimental material Mn content level, to improve the Mn content can improve the high-N austenitic stainless steel low temperature plasticity and toughness, reduce the ductile-brittle transition temperature of 18Cr-12Mn-0.55N steel at low temperature Deformation induced deformation martensite transformation occurs, but the amount of martensitic transformation is small, reducing the temperature on the amount of martensitic transformation had no significant effect.Deformation-induced martensite can improve the work hardening ability of high N austenitic stainless steel, But lowers the ductility and toughness of the steel at low temperature.It is the main reason that brittle fracture occurs at low temperature for Re-Cr-Mn high-N austenitic stainless steel with decreasing of work-hardening and stacking faults with decreasing temperature.