文献类型：期刊文献

中文题名：Enhancing the Hydrogen Embrittlement Resistance of Medium Mn Steels by Designing Metastable Austenite with a Compositional Core-shell Structure

作者：Jun Zhang[1];Binhan Sun[2];Zhigang Yang[1];Chi Zhang[1];Hao Chen[1]

机构：[1]Key Laboratory for Advanced Materials of Ministry of Education,School of Materials Science and Engineering,Tsinghua University,Beijing 100084,China;[2]Key Laboratory of Pressure Systems and Safety,Ministryof Education,School of Mechanical and Power Engineering,East China University of Science and Technology,Shanghai 200237,China

年份：2023

卷号：36

期号：7

起止页码：1059

中文期刊名：Acta Metallurgica Sinica(English Letters)

外文期刊名：金属学报（英文版）

收录：CSTPCD;;Scopus;CSCD:【CSCD2023_2024】；

基金：H.Chen acknowledges financial support from the National Natural Science Foundation of China(Nos.51922054,U1860109 and U1808208);the National Key Research and Development Program of China(2022YFE0110800);Z.G.Yang acknowledges financial support from the National Natural Science Foundation of China(No.52171008);B.Sun acknowledges?nancial support from the National Natural Science Foundation of China(No.52275147).

语种：英文

中文关键词：Medium Mn steels;Hydrogen embrittlement;Core-shell austenite;Chemical heterogeneity;Deformationinduced martensite transformation

摘要：Deformation-induced martensite transformation from metastable retained austenite is one of the most efficient strain-hardening mechanisms contributing to the enhancement of strength-ductility synergy in advanced high-strength steels.However,the hard transformation product(often-martensite)and the H redistribution associated with phase transformation essentially decrease materials’resistance to hydrogen embrittlement.To solve this fundamental conflict,we introduce a new microstructure architecting strategy based on an accurately design of core–shell compositional distribution inside the austenite phase.We employed this approach in a typical medium Mn steel(8 wt.%Mn)with an ultrafine grained austenite-ferrite microstructure.We produced a high Mn content(15–16 wt.%)in the austenite shell region and a low Mn content(~12 wt.%)in the core region,through a thermodynamics-guided two-step austenite reversion treatment.During room-temperature deformation,the austenite core transforms continuously starting from a low strain,providing a high and persistent strain-hardening rate.The transformation of Mn-rich austenite shell,on the other hand,occurs only at the latest regime of the deformation,thus effectively inhibiting the nucleation of H-induced cracks at ferrite/deformation-induced martensite interfaces as well as suppressing their growth and percolation.This step-wise transformation,tailored directly targeted to protect the hydrogen-sensitive microstructure defects(interfaces),results in a significantly enhanced hydrogen embrittlement resistance without sacrificing the mechanical performance in hydrogen-free condition.The design of compositional core–shell structure is expected to be applicable to,at least,other multiphase advanced high-strength steels containing metastable austenite.