不锈钢复合钢筋近界面微观组织演变及元素扩散动力学  

Microstructure Evolution Near Interface and the Element Diffusion Dynamics of the Composite Stainless Steel Rebar

作　　者：郭星星 帅美荣[1] 楚志兵[1] 李玉贵[2] 谢广明[3] GUO Xingxing;SHUAI Meirong;CHU Zhibing;LI Yugui;XIE Guangming(Engineering Research Center Heavy Machinery Ministry of Education,Taiyuan University of Science and Technology,Taiyuan 030024,China;School of Mechanical Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China)

机构地区：[1]太原科技大学重型机械教育部工程研究中心,太原030024 [2]太原科技大学机械工程学院,太原030024 [3]东北大学轧制技术及连轧自动化国家重点实验室,沈阳110819

出　　处：《金属学报》2025年第2期336-348,共13页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目,No.52075357;山西省重点研发计划项目,No.201903D121043;山西省研究生教育创新项目,Nos.2021Y709和2022Y709;轧制技术及连轧自动化国家重点实验室(东北大学)开放课题项目,No.2020RALKFKT013。

摘　　要：不锈钢复合钢筋是一种新型复合结构材料,能够满足海洋服役的苛刻性能需求,从而有效解决基础材料产能过剩问题。产品复合界面质量往往取决于界面微观组织和界面化合物分布等,变形参数则是界面质量控制的基础,通过控制压下率可以获得复合界面均匀且性能优异的产品。本工作针对不锈钢复合钢筋304/Q235开展高温热压缩实验,研究应变速率1 s-1,压下率20%、40%和60%条件下近界面微观组织演变特征,阐明近界面不锈钢侧微观组织动态形核机制以及晶界迁移过程;基于非稳态条件下单向流动的Fick第二定律,建立复合界面过渡区域元素扩散模型,进一步研究界面微观组织演变和元素扩散行为的相关性。结果表明,变形温度为1000℃时,界面两侧晶粒动态再结晶比例不协调,碳钢侧晶粒发生完全动态再结晶,而不锈钢侧晶粒仅在高压下率工况下受位错机制主导发生较为显著的动态再结晶。变形温度为1100℃时,不锈钢侧的动态再结晶由孪生机制主导控制,Σ3孪晶对再结晶过程起加速作用,界面两侧变形协调性显著提高。进一步研究表明,晶粒细化和位错、孪晶等缺陷的移动对元素扩散行为具有促进作用,界面化合物演变和空洞闭合对界面元素扩散行为也具有明显提升效果。此外,采用Boltzmann-Matano法确定Matano面位置,引入LevenberMarquardt多元非线性参数拟合方法,构建的元素扩散模型能够精确反映复合界面过渡区域的元素浓度,为复合材料金属间冶金结合质量提升、界面性能调控提供理论支撑。The composite rebar of stainless steel is used as a new type of structural material and can meet the strict performance requirements of marine service,effectively solving the overcapacity problem of basic materials.The quality of the composite interface generally depends on the interface microstructure and the distribution of interface compounds.However,the deformation parameters also indicate the interface quality,and a composite product with a uniform interface and excellent performance could be obtained by controlling the reduction rate.Herein,high-temperature compression experiments were conducted on the composite materials of 304/Q235.The near-interface characteristics of the microstructure evolution were studied under a strain rate of 1 s-1 and reduction rates of 20%,40%,and 60% to elucidate the dynamic nucleation mechanism and grain boundary migration of the stainless steel side of the interface.Based on Fick ' s second law of one-way flow under unsteady conditions,an element diffusion model of the composite interface transition region was established to explore the correlation between the interface microstructure evolution and element diffusion behavior.The results show that there is an uncoordinated dynamic recrystallization occured on both sides of the interface at the temperature of 1000 oC.The grains completely change during dynamic recrystallization at the carbon steel side of the interface,while the recrystallization dominated by the dislocation mechanism significantly occurs under the working condition with a high pressure rate(60%) at the stainless steel side.At a deformation temperature of 1100 oC,dynamic recrystallization is controlled by the dominant twinning mechanism at the stainless steel side,where Σ3 twinning accelerates the recrystallization process.At this time,the coordination of deformation is significantly improved on both sides of the interface.Further studies show that grain refinement and the movement of dislocation and twin defects have a positive effect on the element diffusion

关 键 词：复合压缩 微观组织演变 孪晶机制 元素扩散动力学 

分 类 号：TB331[一般工业技术—材料科学与工程]