Abstract Low carbon steels containing 15–19 wt% Mn were processed to study the influence of Mn content on the thermally induced and deformation-induced e-/α′-martensitic transformation and tensile properties of high-Mn TRIP steels. The stability of austenite and e-martensite was studied in terms of thermodynamics, and the work hardening behavior during tensile deformation was divided into two stages using Hollomon analysis. The results indicated that Mn increased the stability of austenite and e-martensite and austenite grain refinement had a larger effect on γ → e than γ → α′ transformation. During early stages of tensile deformation, the steel having ~15 wt% Mn continued the γ → e, e → α′ and γ → α′ transformation because deformation energy compensated the Gibbs free energy required for phase transformation. But α′-martensitic transformation was difficult in steel having ~19 wt% Mn even after fracture because of the high stability of e-martensite. On account of high density of dislocations in α′-martensite, the dynamic strain aging process was obvious when deformation-induced α′-martensitic transformation occurred in steel. The significant α′-martensitic transformation and intense dynamic strain aging improved work hardening exponent and ultimate tensile strength of steel, while the coordinated transformation of γ → e and e → α′ during tensile deformation was beneficial to improve ultimate elongation.

中文翻译：

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锰含量对低碳高锰TRIP钢ε-/α'-马氏体相变及拉伸性能的影响

摘要 对含 15-19 wt% Mn 的低碳钢进行加工，研究 Mn 含量对高锰 TRIP 钢的热诱导和变形诱导 e-/α'-马氏体转变和拉伸性能的影响。从热力学角度研究了奥氏体和电子马氏体的稳定性，并使用 Hollomon 分析将拉伸变形过程中的加工硬化行为分为两个阶段。结果表明，Mn增加了奥氏体和e马氏体的稳定性，奥氏体晶粒细化对γ→e的影响大于γ→α′相变。在拉伸变形的早期阶段，含有~15 wt% Mn 的钢继续进行 γ → e、e → α' 和 γ → α' 转变，因为变形能补偿了相变所需的吉布斯自由能。但是，由于 e 马氏体的高稳定性，即使在断裂后，含有~19 wt% Mn 的钢也很难发生 α'-马氏体转变。由于α'-马氏体中位错密度高，钢发生变形诱导α'-马氏体相变时，动态应变时效过程明显。显着的α′-马氏体相变和强烈的动态应变时效提高了钢的加工硬化指数和极限抗拉强度，而拉伸变形过程中γ→e和e→α′的协调转变有利于提高极限伸长率。当钢发生变形诱导的α'-马氏体相变时，动态应变时效过程明显。显着的α′-马氏体相变和强烈的动态应变时效提高了钢的加工硬化指数和极限抗拉强度，而拉伸变形过程中γ→e和e→α′的协调转变有利于提高极限伸长率。当钢发生变形诱导的α'-马氏体相变时，动态应变时效过程明显。显着的α′-马氏体相变和强烈的动态应变时效提高了钢的加工硬化指数和极限抗拉强度，而拉伸变形过程中γ→e和e→α′的协调转变有利于提高极限伸长率。