The effects of Si on the mechanical twinning and strain hardening of Fe-18Mn-0.6C twinning-induced plasticity steel
The effects of Si on the mechanical twinning and strain hardening of Fe-18Mn-0.6C twinning-induced plasticity steel
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DOI：
10.1016/j.actamat.2013.02.031
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发表时间：
2013-05-01
期刊：
影响因子：
9.4
通讯作者：
Lee, Young-Kook
中科院分区：
文献类型：
--
作者：
Jeong, Kookhyun;Jin, Jae-Eun;Lee, Young-Kook
系统地研究了Fe-18Mn-0.6C-1.5Si孪生诱发塑性(TWIP)钢的层错能、位错滑移、机械孪生、应变硬化、屈服强度和拉伸强度。并与Fe-18Mn-0.6C和Fe-18Mn-0.6C-1.5Al TWIP钢的结果进行了比较。每1wt.%Si的SFE降低4MJ·m(-2)。Si的加入提高了屈服强度(主要是由于固溶硬化)和抗拉强度(由于在保持60%以上的大伸长率的同时出现了高应变硬化)。为了研究这种高应变硬化，特别是在低应变下，结合电子背散射衍射仪和透射电子显微镜的优点，定量地估计了一次和二次机械孪晶的体积分数。Fe-18Mn-0.6C-1.5Si TWIP钢中初生孪晶和二次孪晶的体积分数最高，而SFE最低。特别是随着Si的加入，二次机械孪晶的体积分数迅速增加。定量评价了位错储存、机械孪生和动态应变时效(DSA)对三种TWIP钢应变硬化的贡献。添加硅的TWIP钢具有最高的应变硬化，这主要是由于活跃的一次和二次孪晶，而DSA可以忽略不计。相反，添加Al的TWIP钢由于机械孪晶和DSA的减少而表现出最低的应变硬化。(C)2013 Acta Materialia Inc.由Elsevier Ltd.出版。保留所有权利。
The stacking-fault energy (SFE), dislocation slip, mechanical twinning, strain hardening, and yield and tensile strengths were systemically investigated in Fe-18Mn-0.6C-1.5Si twinning-induced plasticity (TWIP) steel. The results were also compared with those for Fe-18Mn-0.6C and Fe-18Mn-0.6C-1.5Al TWIP steels. The SFE decreased by 4 mJ m(-2) per 1 wt.% Si. The addition of Si increased both the yield strength, due mainly to solid solution hardening, and the tensile strength, owing to the high strain hardening that occurred while maintaining a large elongation of over 60%. To examine this high strain hardening, especially at low strains, the volume fractions of the primary and secondary mechanical twins were quantitatively evaluated by combining the merits of electron backscattered diffractometry and transmission electron microscopy. The volume fractions of both the primary and secondary twins were the highest in the Fe-18Mn-0.6C-1.5Si TWIP steel, which had the lowest SFE of the three TWIP steels. In particular, the volume fraction of the secondary mechanical twins increased rapidly with the addition of Si. The contributions of dislocation storage, mechanical twinning and dynamic strain aging (DSA) to the strain hardening were also quantitatively evaluated in the three TWIP steels. The Si-added TWIP steel had the highest strain hardening, due mainly to the active primary and secondary twinning, and experienced negligible DSA. In contrast, the Al-added TWIP steel exhibited the lowest strain hardening due to the reductions in both the mechanical twinning and DSA. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.