金属轧制复合过程微观变形行为的分子动力学建模及研究  

Molecular Dynamics Modeling and Studying of Micro-Deformation Behavior in Metal Roll-Bonding Process

作　　者：张清东[1] 李硕 张勃洋[1] 谢璐 李瑞[1] ZHANG Qingdong;LI Shuo;ZHANG Boyang;XIE Lu;LI Rui(School of Mechanical Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学机械工程学院

出　　处：《金属学报》2019年第7期919-927,共9页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.51575040~~

摘　　要：基于分子动力学方法研究金属层合板轧制复合过程界面区材料的微观变形行为,从力学性能和位错运动的角度,对比研究双金属FeCrNi/Fe与单金属的压缩变形,揭示非共格界面对金属微观变形行为的影响。结果表明,双金属模型与2种单金属模型在应力-应变关系和变形行为规律方面都存在明显差异;由于复合界面的存在,变形过程中双金属模型纯Fe基体中的位错在界面附近积累,界面原子的局部剪切作用使FeCrNi基体中的位错形成变得容易,降低了 FeCrNi基体的屈服强度;复合界面对于变形过程中位错传播的阻碍作用,使材料抵抗塑性变形的能力得到提高,变形过程中2种金属基体内位错密度的交替变化导致2种金属基体的变形量也对应呈现交替变化的特殊现象。Stainless steel/carbon steel bimetallic products, which have the characteristic corrosion resistance of stainless steel as well as the characteristics of high strength and low cost of carbon steel,have been widely used in petrochemical, aviation, shipping and other industries. Roll-bonding is an efficient solid-phase joining method for industrial production of bimetallic products. Different from diffusion bonding and friction welding process, the atoms bond and diffuse at interface while the base metal undergoes severe plastic deformation in the process of roll-bonding. In present work, the micro-deformation behavior in the interfacial area of stainless steel/carbon steel during roll-bonding process is studied based on the molecular dynamics method. Firstly, the applicability of the potential function for the bimetallic composite models with different lattice structures was discussed. Then bimetallic model of FeCrNi/Fe and single metal model of FeCrNi, Fe were established. The effect of non-coherent interface on the deformation behavior was revealed by comparing the deformation process of three models. The results show that the mechanical properties and deformation processes of bimetal and single metal are different in the process of deformation bonding. Due to the existence of non-coherent interface, the dislocation in pure Fe matrix is accumulated at the interface during deformation. The local shear effect of interface atoms makes the dislocation formation in FeCrNi matrix easier, thus reducing the yield strength of FeCrNi matrix. The effect of interface on dislocation propagation during alternation makes the dislocation density change alternately in the two matrixes, which improves the ability of material to resist plastic deformation.In addition, the alternately change of the dislocation density within the two matrixes during the deformation process leads to the special phenomenon that the deformation of the two matrixes is alternately changed.

关 键 词：分子动力学 304不锈钢/Q235碳钢 FeCrNi/Fe 轧制复合 

分 类 号：TG331[金属学及工艺—金属压力加工]