预处理条件对QP980钢组织及塑性失稳行为的影响  

Effect of Pretreatment Conditions on Microstructure and Plastic Instability Behavior of QP980 Steel

作　　者：张鹏 李兵 徐飞越 汪锐杰 王敏 ZHANG Peng;LI Bing;XU Feiyue;WANG Ruijie;WANG Min(College of Materials Science and Engineering,Hubei University of Automotive Technology,Shiyan 442002,Hubei,China;Hubei Longzhong Laboratory,Wuhan University of Technology Xiangyang Demonstration Zone,Xiangyang 441000,Hubei,China)

机构地区：[1]湖北汽车工业学院材料科学与工程学院,湖北十堰442002 [2]湖北隆中实验室,湖北襄阳441000

出　　处：《材料导报》2025年第8期220-225,共6页Materials Reports

基　　金：湖北隆中实验室自主创新项目资助(2022ZZ-30);湖北省重点研发计划(2021BAB019);大学生创新创业训练计划项目(S202310525032)。

摘　　要：吕德斯应变的存在会显著影响先进高强钢的冲压成形性能。本工作通过合理设计预处理条件对QP980钢的微观组织及塑性失稳行为进行分析研究。结果表明:经过预应变(4%)和热处理(300℃/10 min)后,能显著提升QP980钢的强度性能。在综合延伸率仅降低2.9%的前提下,抗拉强度值提升150 MPa,屈服强度值增加466 MPa。这得益于回火过程中过渡碳化物的弥散强化以及相变诱导塑性效应。此外,经预应变和回火热处理后的QP980钢呈现出了明显的吕德斯应变特征。通过分离预处理条件进行对比研究发现:残余奥氏体的稳定性是影响QP980钢是否发生吕德斯应变的主要因素,预应变和回火过程皆会消耗掉部分不稳定残余奥氏体。在残余奥氏体稳定性过高时,这意味着较小应变条件下相变诱导塑性效应不易发生,此时塑性失稳现象容易出现,拉伸变形过程中会产生吕德斯带。The impact of Lüders strain on the formability of advanced high strength steels is significant.In this work,through a well-designed set of preconditioning conditions,the microstructure and plastic instability behavior of QP980 steel was examined.The findings reveal that prestraining(4%)and subsequent heat treatment(300℃/10 min)can greatly enhance the strength properties of QP980 steel.Despite a slight reduction of only 2.9%in comprehensive elongation,the tensile strength value acquires a remarkable increase of 150 MPa and the yield strength value rises by 466 MPa.These improvements are attributed to the diffusion strengthening of transition carbides and the plastic effect induced by phase change during tempering.Moreover,QP980 steel treated with pre-strain and tempering exhibits distinct Lüders strain characteristics.The study identifies the stability of residual austenite as a key factor influencing the occurrence of Lüders strain in QP980 steel,with some unstable residual austenite being eliminated during the pre-strain and tempering process.Excessive stability of residual austenite hinders the plastic effect induced by phase change under low strain conditions,leading to plastic instability and the formation of Lüders bands during tensile deformation.

关 键 词：QP980 相变诱导塑性效应 预应变 吕德斯应变 残余奥氏体稳定性 

分 类 号：TG142.1[一般工业技术—材料科学与工程]