中文摘要：

利用四辊异步冷轧机轧制工业纯铜极薄带,对轧制出厚度为25 ~300 p m 的轧件进行拉伸实验,发现在其力学性能方面出现了尺寸效应现象：随着厚度的减小,材料抗拉强度先增大,达到某-厚度临界值后转而减小,即存在-个厚度阈值,在此阈值之前出现加工硬化,之后转为加工软化.针对这-现象,对轧件进行机械性能检测和EBSD等观察或分析,认为极薄带出现尺寸效应的原因是：随着轧件厚度的减薄,胞壁沿厚度方向尺寸大幅度减小,位错向胞壁迁移距离减小,异号位错在胞壁处湮灭,导致抗拉强度降低.

英文摘要：

The mechanical tests and EBSD （ electron backscattered diffraction） analysis of industrially pure copper foil with thickness of 25 ？300 pm rolled by asymmetric rolling process had been conducted to study the size effect phenomenon. The size effect of copper foils with different thickness was found, i. e. the tensile strength and hardness first increased and then decreased with the decrease of foil thickness when the thickness reached the critical value. The mechanical property trended to change at the thickness threshold. The work hardening with the decrease of thickness only happened when the foil thickness was bigger than the thickness threshold. And when the foil thickness was less than the thickness threshold, work softening happened. The reason why size effect happened was that the grains were stretched,flattened even pulled off as the thickness of foil decreased so little new grains provided vast grain boundary which made the dislocation density decrease.