中文摘要：

为了对实验观察到的纳晶Cu的高强度、高塑性给予合理的解释,建立了包含2种晶粒的材料模型：最细小晶粒（2~4 nm）和普通纳晶晶粒（20~100 nm）.最细小晶粒可以看作普通纳晶晶粒的三晶交组成部分,普通纳晶晶粒由晶界影响区和晶内相组成.接着,分别建立晶界影响区和晶内相变形的本构方程.与文献实验结果进行了对比并获得了一致的结果.详细分析了最细小晶粒对于纳晶材料位错堆积能力和塑性的影响,证明其存在是材料高强度高塑性的成因.

英文摘要：

In order to discuss the experimental observation results of nanocrystalline Cu which exhibits enhanced strength and reasonably good ductility,a new material model was proposed.The model contained two types of grains：finest grains and normal nanograins.The finest grains and normal grains denote the grains with size 2-4 nm and 20-100 nm,respectively.The finest grains could be treated as part of triple junction of normal grains,the normal nanograins were comprised of grain interior and grain boundary affected zone.Then,constitutive equations were built to predict the deformation behaviors of grain boundary affected zone and grain internal part.The effects of the existence of the finest grains on strength and ductility of nanocrystalline materials were discussed in detail.The result showed that the existences of the finest grains contributed to simultaneous high strength and good ductility.