Grain size altering yielding mechanisms in ultrafine grained high-Mn austenitic steel:Advanced TEM investigations

作     者：Chang-Yu Hung Yu Bai Nobuhiro Tsuji Mitsuhiro Murayama Chang-Yu Hung;Yu Bai;Nobuhiro Tsuji;Mitsuhiro Murayama

作者机构：Department of Materials Science and EngineeringVirginia TechBlacksburgVA24061USA Department of Materials Science and EngineeringKyoto UniversityYoshida-honmachiSakyo-kuKyoto606-8501Japan Elements Strategy Initiative for Structural MaterialsKyoto UniversityYoshida-honmachiSakyo-kuKyoto606-8501Japan Institute for Materials Chemistry and EngineeringKyushu UniversityKasugaFukuoka8168580Japan 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2021年第86卷第27期

页      面：192-203页

核心收录：

学科分类：0817[工学-化学工程与技术] 0806[工学-冶金工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：supported by NSF(ECCS 1542100,2025151) financial support by the JST CREST(JPMJCR1994) financial support by JSPS KAKENHI Grant Numbers(19H02029,20H02479) financial support by Elements Strategy Initiative for Structural Materials(ESISM,No.JPMXP0112101000) the Grant-in-Aid for Scientific Research(S)(No.15H05767),the Grant-in-Aid for Scientific Research(A)(No.20H00306) 

主　　题：Ultrafine grains TWIP steel Yield-drop phenomenon Deformation twin nucleation Structural defects Transmission electron microscopy 

摘      要：The underlying mechanism of discontinuous yielding behavior in an ultrafine-grained(UFG)Fe-31 Mn-3 Al-3 Si(wt.%)austenitic TWIP steel was investigated by the use of advanced TEM technique with taking the plastic deformation mechanisms and their correlation with grains size near the macroscopic yield point into *** yield drop mechanisms such as the dislocation locking by the Cottrell atmosphere due to the presence of interstitial impurities cannot explain the origin of this phenomenon in the UFG high-Mn austenitic TWIP ***,we experimentally revealed that the plastic deformation mechanisms in the early stage of deformation,around the macroscopic yield point,show an obvious association with grain *** specifically,the main mechanism shifts from the conventional slip in grain interior to twinning nucleated from grain boundaries with decreasing the grain size down to less than 1μ*** observation indicates that the grain size dependent deformation mechanisms transition is also deeply associated with the discontinuous yielding behavior as it could govern the changes in the grain interior dislocation density of mobile dislocations around the macroscopic yield point.