冷轧对Fe-28Mn-8Al-1C低密度钢微观组织和力学性能的影响  

Effect of cold rolling on microstructure and mechanical properties of Fe-28Mn-8Al-1C low density steel

作　　者：栾泽伟 熊毅[1,2] 厉勇 杜楠[4] 李华飞 任凤章 LUAN Zewei;XIONG Yi;LI Yong;DU Nan;LI Huafei;REN Fengzhang(School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang 471023,Henan,China;Provincial and Ministerial Co-construction of Collaborative lnnovation Center for Non-ferrous Metal New Materials and Advanced Processing Technology,Luoyang 471023,Henan,China;Institute of Special Steels,Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China;Luoyang Optoelectronic Technology Development Center,Luoyang 471003,Henan,China)

机构地区：[1]河南科技大学材料科学与工程学院,河南洛阳471023 [2]有色金属新材料与先进加工技术省部共建协同创新中心,河南洛阳471023 [3]钢铁研究总院有限公司特殊钢研究院,北京100081 [4]洛阳光电技术发展中心,河南洛阳471003

出　　处：《钢铁》2024年第10期96-106,共11页Iron and Steel

基　　金：“十四五”国家重点研发计划资助项目(2022YFB3705200);国家自然科学基金资助项目(U1804146,51905153,52111530068);河南省重大专项资助项目(221100230200)。

摘　　要：为了实现“碳达峰”和“碳中和”的战略目标,汽车轻量化已成为汽车工业的迫切需求。Fe-Mn-Al-C低密度钢因具有低密度和优异的力学性能被认为是第三代汽车用钢的候选材料之一。冷轧作为汽车用钢应用过程中的重要环节,其对低密度钢微观组织和力学性能的影响尚不明确,因此,通过对Fe-28Mn-8Al-1C奥氏体低密度钢进行不同变形量的冷轧变形,并借助光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、电子背散射衍射(EBSD)、显微硬度计和万能拉伸试验机系统研究了冷轧对低密度钢微观组织和力学性能的影响。结果表明,随着冷轧变形量的增加,试验钢晶粒由等轴状沿轧制方向逐渐被拉长,同时晶内产生大量滑移带,以协调剧烈的塑性变形,最终在90%变形量下形成纤维组织。冷轧过程中位错滑移是塑性变形的主要机制,在低应变条件下,试验钢表现出位错平面滑移特征,形变亚结构为相互平行的滑移带,相应的形变织构为Copper织构;而在高应变条件下,则表现出交滑移的特征,形变亚结构为位错墙和位错胞,并且Copper织构逐渐转变为Brass织构。变形导致试验钢位错密度急剧增加,位错交互作用显著加强,在90%变形量下,试验钢的晶粒尺寸细化至76.5 nm。试验钢的强度、硬度随着变形量的增加而显著增大,但伸长率则急剧下降,在90%变形量下,钢的抗拉强度、屈服强度和硬度达到最大,分别为1706 MPa、1653 MPa和531HV,伸长率则下降至5.3%。相应的断口形貌则由固溶态的韧性断裂转变为90%变形后的韧脆混合性断裂。The urgent imperative within the automotive industry to realize the strategic objectives of"carbon peaking"and"carbon neutrality"has underscored the critical necessity for automobile lightweighting.Based on the merits of low density and excellent mechanical properties,Fe-Mn-Al-C low density steel is considered as one of the candidate materials for the third-generation automobile steel.Nonetheless,the application process of automobile steel entails a pivotal stage in the form of cold rolling,the ramifications of which on the microstructure and mechanical properties of low-density steel remain unclear.Therefore,cold rolling deformation of Fe-28Mn-8Al-1C austenitic low-density steel with different deformation amounts was carried out.The effect of cold rolling on the microstructure and mechanical properties of Fe-28Mn-8Al-1C austenitic low-density steel was systematically investigated by optical microscope(OM),scanning electron microscope(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),electron backscattering diffraction(EBSD),micro-hardness tester,and universal tensile testing machine.The results show that the grains of the tested steel are elongated gradually along the rolling direction from equiaxial shape with the increase of cold rolling deformation,and a large number of slip bands are generated within the grains to coordinate the severe plastic deformation,which eventually form a fibrous tissue at 90%deformation.Dislocation slip is the main mechanism of plastic deformation during cold rolling.Under low strain condition in which the deformation substructure is parallel slip bands,the corresponding deformation texture of the steel which exhibit dislocation slip characteristics is Copper texture.Under high strain condition,the steel exhibits cross slip characteristics,the deformation substructure is dislocation wall and dislocation cell,and the Copper texture gradually transforms into Brass texture.The grain size of the steel was refined to 76.5 nm at 90%deformation,because of a sharp increase in

关 键 词：低密度钢 冷轧 微观组织 力学性能 织构 

分 类 号：TG142.1[一般工业技术—材料科学与工程]