波纹轧制制备Cu/Al复合板的应力分析及显微组织演变

Stress analysis and microstructure evolution of Cu/Al composite plate during corrugated rolling

建立三维有限元模型,并通过50%压下量的轧制试验验证模型的准确性。从时间角度分析整个波纹轧制过程中金属的流动规律。金属经历的变形可以分为两个阶段:填充阶段和压下阶段。填充阶段应力变化较为复杂,而压下阶段应力变化趋势一致。通过罗德参数和应力三轴度分析特征位置的应力状态,在开始变形时为两向拉应力一向压应力。采用EBSD技术分析Cu板的显微组织演变过程。与原始板材相比,铜板各特征位置晶粒均发生细化,而Cu板波谷处晶粒在发生细化后有长大的现象,这是由剧烈塑性变形产生的绝热温升现象造成的。

A 3D finite element model was developed.The accuracy of the model was verified through a rolling experiment in which the reduction rate of the plate was 50%.The metal flow law in the rolling process was analyzed from the perspective of time during the whole corrugated rolling process.The deformation experienced by all metal particles is divided into two periods:the filling period and the extension period.The stress change is complex during the filling period,but the stress change trend is approximate during the extension period.The stress state of characteristic positions is two tensile stresses and one compressive stress when the plate starts to deform,which was analyzed by the Lode angle parameter and triaxiality parameter.The microstructure evolution of the Cu plate was analyzed using electron backscatter diffraction(EBSD)technology.Compared with the initial plate,grain refinement occurs at each characteristic position of the Cu plate.There is a phenomenon of grain growth at the trough of the Cu plate after refinement due to the adiabatic temperature increase caused by severe plastic deformation.