Review on the plastic instability of medium -Mn steels for identifying the formation mechanisms of Lüders and Portevin -Le Chatelier bands  

作　　者：Bin Hu Han Sui Qinghua Wen Zheng Wang Alexander Gramlich Haiwen Luo 

机构地区：[1]School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China [2]Steel Institute,RWTH Aachen University,Intzestraße 1,52072 Aachen,Germany

出　　处：《International Journal of Minerals,Metallurgy and Materials》2024年第6期1285-1297,共13页矿物冶金与材料学报（英文版）

基　　金：support from the National Natural Science Foundation of China(Nos.51831002,51904028,and 52233018);the Beijing Municipal Natural Science Foundation(No.2242048);the Fundamental Research Funds for the Central Universities,China(No.FRF-EYIT-23-08).

摘　　要：Plastic instability,including both the discontinuous yielding and stress serrations,has been frequently observed during the tensile deformation of medium-Mn steels(MMnS)and has been intensively studied in recent years.Unfortunately,research results are controversial,and no consensus has been achieved regarding the topic.Here,we first summarize all the possible factors that affect the yielding and flow stress serrations in MMnS,including the morphology and stability of austenite,the feature of the phase interface,and the deformation parameters.Then,we propose a universal mechanism to explain the conflicting experimental results.We conclude that the discontinuous yielding can be attributed to the lack of mobile dislocation before deformation and the rapid dislocation multiplication at the beginning of plastic deformation.Meanwhile,the results show that the stress serrations are formed due to the pinning and depinning between dislocations and interstitial atoms in austenite.Strain-induced martensitic transformation,influenced by the mechanical stability of austenite grain and deformation parameters,should not be the intrinsic cause of plastic instability.However,it can intensify or weaken the discontinuous yielding and the stress serrations by affecting the mobility and density of dislocations,as well as the interaction between the interstitial atoms and dislocations in austenite grains.

关 键 词：medium manganese steel discontinuous yielding stress serrations retained austenite dislocations 

分 类 号：TG142.1[一般工业技术—材料科学与工程]