(1. 铜陵学院 机械工程学院，铜陵 244061；
2. 东北大学 轧制技术及连轧自动化国家重点实验室，沈阳 110819；
3. 安徽工业大学 冶金工程学院，马鞍山 243032)
摘 要: 采用退火态轧制铜箔为原料，进行晶粒尺寸效应的箔轧实验和晶体塑性有限元模拟。基于率相关晶体塑性理论，开发用户材料子程序(UMAT)，建立轧制铜极薄带的晶体塑性有限元模型，改进Voronoi图种子生成的随机性，建立反映晶粒形貌、晶界不规则性的多晶极薄带几何模型，并编写赋予多晶取向的算法，用以控制多晶取向及织构分布，研究晶粒尺寸效应对其变形机制的影响。结果表明：在铜极薄带中尺寸较小晶粒中产生的剪切带相对于尺寸较大晶粒中产生的要均匀，可较好地减小变形局部化；不同晶粒尺寸铜极薄带的滑移系启动和累积滑移存在显著差异，启动的滑移系随晶粒尺寸的减小而增多；表层晶粒和内部晶粒的约束差异导致变形后晶粒取向主要绕横向(TD)进行旋转，旋转角度和极点分散度随晶粒平均尺寸的减小而减小。箔轧实验和模拟得到的轧制 力-晶粒尺寸曲线基本一致，即晶粒取向对轧制力的影响随晶粒平均尺寸的减小而减弱。
关键字: 极薄带轧制；多晶模型；晶体塑性有限元；晶粒尺寸效应
（1. School of Mechanical Engineering, Tongling University, Tongling 244061, China;
2. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China;
3. School of Metallurgical Engineering, Anhui University of Technology, Maanshan 243032, China）
Abstract:Annealed pure copper foils were taken as raw materials, and after the processes of foil rolling, the grain size effect was studied by foil rolling experiment and crystal plasticity finite element simulation. A user defined material subroutine (UMAT) developed based on the rate-dependent crystal plasticity theory embedded into the finite element software to analyze the grain size effect on micro-scale deformation mechanism of rolling polycrystalline copper ultra-thin strip. The random generating of the Voronoi diagram seeds was improved. The polycrystalline ultra-thin strip geometry model was created by constructing a new seeds generation algorithm, which can express the shape of the grains and the irregular grain boundaries. An algorithm to describe the grain orientation and texture distribution was introduced by adjusting the modeling parameters. The results show that the shear bands in small grain size are more uniform than those in large grain size which could effectively reduce the rolling deformation locality. The activity of slip system and accumulated slip are significant different in the foils with different grain sizes, and the activity of slip systems increases with decreasing grain size. The rotate of crystallographic orientation mainly around the transverse direction attributes to the different constraint of surface grain and internal grain, and the growth of rotation angle and dispersion degree decreases with decreasing grain size. The effect of grain orientation on roll force is weakened with decreasing grain size, and the roll force-grain size curves from the simulation agree well with the rolling experimental results.
Key words: foil rolling; polycrystalline model; crystal plasticity finite element; grain size effect
