采用电解沉积技术制备出无孔隙、无污染、微观应变很小的"理想"纳米晶体单质Cu样品.对电解沉积纳米晶体Cu进行冷轧处理,首次发现纳米晶体材料具有室温下的超塑延展性,在冷轧过程初始阶段样品有少量的加工硬化,当变形量达到一定程度时(ε＞800%),加工硬化效应消失.恒定的晶粒尺寸,恒定的位错密度,以及恒定的硬度值,说明纳米晶体Cu的塑性变形机制由晶界行为所控制,并非位错运动机制.系统的研究了纳米晶体中微观应变对其热稳定性的影响,发现随纳米晶Cu样品中微观应变的增加,晶粒长大的起始温度升高,而微观应变释放的起始温度下降.%A bulk nanocrystalline (nc) pure copper with a high purity and a high density was synthesized by means of electrodeposition. An extreme extensibility (elongation exceeds 5000%) without strain hardening effect was observed when the nc Cu specimen was rolled at room temperature. Microstructure analysis suggests that the superplastic extensibility of the nc Cu originates from a deformation mechanism dominated by grain boundary activities rather than lattice dislocation. This behavior demonstrates new possibilities for scientific and technological advancements of nc materials. Meanwhile, the thermal stability and tensile properties of this nc Cu sample were investigated in this thesis.
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