Pre-strain effects on critical stress and hydrogen content for hydrogen-induced quasi-cleavage fracture in a TRIP-aided bainitic ferrite steel: Martensitic transformation, matrix damage, and strain aging
Pre-strain effects on critical stress and hydrogen content for hydrogen-induced quasi-cleavage fracture in a TRIP-aided bainitic ferrite steel: Martensitic transformation, matrix damage, and strain aging
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DOI：
10.1016/j.ijhydene.2020.07.036
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发表时间：
2020-07
影响因子：
7.2
通讯作者：
Bakuya Kumai;Tomohiko Hojo;M. Koyama;E. Akiyama;H. Waki;A. Nagasaka
中科院分区：
文献类型：
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作者：
Bakuya Kumai;Tomohiko Hojo;M. Koyama;E. Akiyama;H. Waki;A. Nagasaka
在这项研究中，我们的特征在于的微观结构，变形/断裂行为，和氢含量的预应变效果的细节，相对于在TRIP辅助贝氏体铁素体钢的真实断裂强度。三种类型的氢脆行为进行了区分，基于预应变和氢含量。预应变降低了残余奥氏体的分数，这反过来又降低了氢含量低时的氢脆敏感性。然而，进一步的预应变增加位错密度，这有三个主要影响：氢含量的增加，加工硬化和应变时效硬化。已发现氢含量增加超过4质量ppm会使真实断裂强度从约1.5 GPa降低至1.2 GPa。发现加工硬化和应变时效硬化增加，直到相对于应变达到临界断裂应力;这导致伸长率降低，特别是当氢含量高时。
In this study, we characterized the details of the pre-strain effects on the microstructure, deformation/fracture behavior, and hydrogen content, with respect to the true fracture strength in the TRIP-aided bainitic ferrite steel. Three types of hydrogen embrittlement behavior were distinguished, based on pre-strain and hydrogen content. Pre-strain reduces the fraction of retained austenite, which in turn decreases the hydrogen embrittlement susceptibility when the hydrogen content is low. However, further pre-straining increases dislocation density, which has three main effects: an increase in hydrogen content, work hardening, and strain-age hardening. The increase in the hydrogen content that exceeds 4 mass ppm has been found to decrease the true fracture strength from approximately 1.5 to 1.2 GPa. The work hardening and strain-age hardening were found to increase until the critical fracture stress was achieved with respect to the strain; this led to a reduction in the elongation, particularly when the hydrogen content was high.