基于TRIP效应的复相钢的组织特征及强塑性机制  

Microstructure characteristics and mechanism of strength and plasticity of complex phase steel based on the TRIP effect

作　　者：侯晓英 丁明凯 刘万春 郝亮 王业勤 初林 HOU Xiao-ying;DING Ming-kai;LIU Wan-chun;HAO Liang;WANG Ye-qin;CHU Lin(Shandong Iron&Steel Group Rizhao Co Ltd,Rizhao 276805,China)

机构地区：[1]山东钢铁集团日照有限公司,山东日照276805

出　　处：《材料热处理学报》2024年第4期103-112,共10页Transactions of Materials and Heat Treatment

基　　金：日照市自然科学基金项目(优秀青年基金项目)(RZ2021ZR10)。

摘　　要：采用扫描电镜(SEM)、电子背散射衍射(EBSD)技术和透射电镜(TEM)对复相钢的微观形貌进行表征,并研究了其基于相变诱导塑性(TRIP)效应的强塑性机制。结果表明,将退火温度设定在单相奥氏体区和(γ+α)两相临界区,由于微观形貌特征的不同致使试验钢的力学性能有着显著的区别。退火温度(915℃)在单相奥氏体区时,微观组织由27%先共析铁素体、56%块状贝氏体以及分布于晶界处的17%残留奥氏体组成;组织中的先共析铁素体,其塑性优于再结晶铁素体,更有利于发挥协调变形作用,通过缓解应力对残留奥氏体的作用而有效发挥其TRIP效应;同时均匀分布于晶界处纵横比>2.0的块状残留奥氏体,在变形过程中由于受到相界面及块状硬质相贝氏体的阻碍,TRIP效应的贡献较大且可在整个应变阶段持续地发生。在晶粒尺寸、组织形貌、晶体学结构、V(C,N)析出和位错塞积,以及TRIP效应的共同作用下,915℃退火后复相钢的综合力学性能最优,屈服强度和抗拉强度分别为756和1135 MPa,强塑积可达到26.446 GPa·%,同时具有优良的伸长率和扩孔性能,分别为23.3%和56%。Microstructure of complex phase steel was characterized using scanning electron microscopy(SEM),electron backscatter diffraction(EBSD)technique and transmission electron microscopy(TEM),and its mechanism of strength and plasticity based on the transformation induced plasticity(TRIP)effect was studied.The results show that when the annealing temperature is in the single-phase austenite zone and the(γ+α)two-phase critical zone,there are significant differences in the mechanical properties of the experimental steel due to the different microstructure characteristics.When the annealing temperature is 915℃which is in the single-phase austenite zone,the microstructure of the experimental steel consists of 27%proeutectoid ferrite,56%block bainite and 17%retained austenite distributed at grain boundaries.the proeutectoid ferrite in the microstructure has better plasticity than the recrystallized ferrite,which is more conducive to coordinating deformation and effectively exerting its TRIP effect by relieving the effect of stress on the retained austenite.At the same time,blocky retained austenite with a aspect ratio greater than 2.0 uniformly distributed at grain boundaries is hindered by the phase interface and blocky hard phase bainite during the deformation process,and the TRIP effect contributes significantly and can continue to occur throughout the entire strain stage.Under the combined effects of grain size,microstructure,crystallographic structure,V(C,N)precipitation and dislocation packing,as well as TRIP effect,the comprehensive mechanical properties of the complex phase steel annealed at 915℃are the best,with yield strength and tensile strength of 756 and 1135 MPa,respectively,and product of strength and plasticity reaching 26.446 GPa·%.At the same time,it has excellent elongation and expansion performance,which are 23.3%and 56%,respectively.

关 键 词：复相钢 TRIP效应 强塑性机制 残留奥氏体稳定性 协调变形 

分 类 号：TG142.3[一般工业技术—材料科学与工程]