Cu addition effects on TRIP to TWIP transition and tensile property improvement of ultra-high-strength austenitic high-Mn steels
Cu addition effects on TRIP to TWIP transition and tensile property improvement of ultra-high-strength austenitic high-Mn steels
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DOI：
10.1016/j.actamat.2018.12.044
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发表时间：
2019-03-01
期刊：
影响因子：
9.4
通讯作者：
Lee, Sunghak
中科院分区：
文献类型：
--
作者：
Choi, Jin Hyeok;Jo, Min Chul;Lee, Sunghak
奥氏体型高锰钢是理想的超高强度冷轧钢，其力学性能因其强大的变形相变机制和孪生诱发塑性(TRIP和TWIP)而得到极大改善。在本研究中，为了获得良好的强塑性平衡，提出了一种奥氏体型高锰TRIP钢，并添加了1-2wt.%的铜作为增加层错能的元素和奥氏体稳定剂，以实现从TRIP到TWIP的过渡。未加铜的钢具有最高的屈服强度(502 Mpa)和最高的抗拉强度(1137 Mpa)，而锯齿形流动的延伸率最低(34.6%)。屈服强度和抗拉强度随铜含量的增加而降低，而延伸率在添加1%铜的钢中最高。TRIP和TWIP机制在考虑(Mn，Cu)偏析带的情况下与计算的SFE符合得很好。在未加铜的钢中，随着局部变形带穿过试件厚度段以激活锯齿状流动，TRIP是逐步发生的，随着铜含量的增加，TRIP转变为TWIP可以减少(或改善)TRIP。在添加1%铜的钢中，由于TRIP和TWIP被很好地均化，产生了协同效应，整体拉伸性能得到了改善(屈服强度：461 Mpa，拉伸强度；1093 Mpa，伸长率；65.1%)。(C)2018 Acta Materialia Inc.由Elsevier Ltd.出版。保留所有权利。
Austenitic high-Mn steels have been nominated as desirable ultra-high-strength cold-rolled steels whose mechanical properties are greatly improved by powerful deformation mechanisms of transformation and twinning-induced plasticity (TRIP and TWIP). In this study, an austenitic high-Mn TRIP steel was suggested to achieve a good strength-ductility balance, and 1-2 wt.% Cu was added as an element for increasing stacking fault energy (SFE) as well as an austenite stabilizer to exploit a transition from TRIP to TWIP. The non-Cu-added steel showed the highest yield and tensile strengths (502 MPa and 1137 MPa, respectively) and the lowest elongation (34.6%) with a serrated flow. Yield and tensile strengths decreased with increasing Cu content, while the elongation was the highest in the 1%-Cu-added steel. TRIP and TWIP mechanisms showed good agreements with calculated SFEs in consideration of (Mn,Cu)-segregated bands. In the non-Cu-added steel, the TRIP occurred step by step as localized deformation bands passed through the specimen gage section to activate the serrated flow, which were reduced (or improved) by the transition from TRIP to TWIP with increasing Cu content. In the 1%-Cu-added steel, overall tensile properties were improved (yield strength; 461 MPa, tensile strength; 1093 MPa, elongation; 65.1%) as both TRIP and TWIP were well homogenized to produce synergic effects. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.