应变速率对18Cr-12Mn-0.55N高氮奥氏体不锈钢塑性流变行为的影响

研究了拉伸应变速率对高氮奥氏体不锈钢18Cr-12Mn-0.55N（质量分数/%）室温力学性能和塑性流变行为的影响.结果表明,随应变速率的升高,实验钢的屈服强度R0.2增大,断后延伸率A减小,抗拉强度Rm略有降低,断面收缩率Z变化不大;在各应变速率下,实验钢的塑性流变行为均可用Ludwigson模型进行描述;随应变速率的升高,实验钢的加工硬化能力和发生屈服时第一根位错开动所需的短程作用力降低;增大应变速率促进多系滑移和交滑移,降低瞬变应变,使实验钢的塑性流变行为在更低的应变水平符合Ludwik模型.

Effect of strain rate on plastic flow behavior of 18Cr-12Mn-0.55N high nitrogen austenitic stainless steel

The effects of strain rate on tensile properties and plastic flow behaviors of 18Cr-12Mn-0.55N high nitrogen stainless steel at room temperature were studied.The results show that with the increase of strain rate,the yield strength R0.2 of the tested steel increases,the elongation A decreases obviously,tensile strength Rm decreases slightly,and the area reduction Z has no abrupt change.The plastic flow behavior of the tested steel can be modeled by Ludwigson equation at all strain rates.At high strain rate,both the work-hardening ability and the short range stress needed for the first dislocation movement decreases.The increase of strain rate promotes multiple slip and cross-slip and decreases transient strain,as a result,plastic flow behavior of the tested steel can be modeled by Ludwik equation at lower strain region.