The effect of Si on hydrogen embrittlement of Fe-18Mn-0.6C-xSi twinning-induced plasticity steels
The effect of Si on hydrogen embrittlement of Fe-18Mn-0.6C-xSi twinning-induced plasticity steels
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DOI：
10.1016/j.actamat.2015.10.015
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发表时间：
2016-01
期刊：
影响因子：
9.4
通讯作者：
Sang Min Lee;I. Park;Jae-Gil Jung;Young Kook Lee
中科院分区：
文献类型：
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作者：
Sang Min Lee;I. Park;Jae-Gil Jung;Young Kook Lee
研究了Fe-18 Mn-0.6C-xSi（wt.%）合金的氢脆性能。通过慢应变速率拉伸试验（SSRTs）和电化学充氢试样的热脱附分析，研究了孪晶诱导塑性（TSTK）钢。无氢加硅钢表面仅为（Fe，Mn）O层，具有立方晶系结构，而加硅钢表面为双氧化物层，外层为（Fe，Mn）O和（Fe，Mn）2SiO 4的混合物，具有正交晶系结构，内层仅为（Fe，Mn）2SiO 4。随着Si含量的增加，（Fe，Mn）2SiO 4层变厚，H含量降低。该结果表明，（Fe，Mn）2SiO 4层有效地抑制了H的渗透。随着含氢铁素体钢中Si含量的增加，伸长率损失（Eloss）和脆性断裂区面积分数均增加，特别是在3 wt.% Si钢，虽然H浓度略有下降，随着Si浓度的增加。带H电荷的无Si和1.5重量%在SSRT过程中，硅钢经历了机械孪晶以及H原子从晶格、位错和晶界向机械孪晶的迁移。无Si和1.5wt.%的Si的脆性均小于1.5wt.%。Si钢是由H集中的机械孪晶引起的。带H的3 wt.% Si钢在SSRT过程中发生了ε-马氏体相变和机械孪晶。当应变达到0.24时，H原子迁移为机械孪晶，进一步应变时，H原子主要继承为ε马氏体。含氢3 wt.%的聚乙烯的损失较大，Si钢主要由高氢ε马氏体引起。
The hydrogen embrittlement (HE) of Fe-18Mn-0.6C-xSi (wt.%) twinning-induced plasticity (TWIP) steels was investigated through slow strain rate tensile tests (SSRTs) and thermal desorption analyses of electrochemically H-charged specimens. Whereas the H-charged Si-free steel showed only the (Fe,Mn)O layer with afcccrystal structure on the surface, the Si-added steels had double oxide layers; the outer layer was a mixture of (Fe,Mn)O and (Fe,Mn)2SiO4with an orthorhombic crystal structure and the inner layer was only (Fe,Mn)2SiO4. When the Si concentration increased, the (Fe,Mn)2SiO4layer became thicker and the charged H concentration decreased. This result indicates that the (Fe,Mn)2SiO4layer is effective in suppressing the permeation of H. Both the elongation loss (Eloss) and the area fraction of the brittle-fractured region increased with increasing Si concentration in the H-charged TWIP steels, particularly in the 3 wt.% Si steel, although the H concentration slightly decreased with increasing Si concentration. The H-charged Si-free and 1.5 wt.% Si steels underwent mechanical twinning and the migration of H atoms from lattices, dislocations and grain boundaries to mechanical twins during the SSRTs. The brittleness of both Si-free and 1.5 wt.% Si steels was caused by H-concentrated mechanical twins. The H-charged 3 wt.% Si steel underwent ε-martensitic transformation as well as mechanical twinning during the SSRT. H atoms migrated to mechanical twins until a strain of 0.24, and then inherited primarily into ε-martensite with further strain. The great Elossof the H-charged 3 wt.% Si steel was caused mainly by H-concentrated ε-martensite.