【摘要】 细化晶粒是改善材料性能的有效手段 ,传统的压力加工技术 (如轧制、挤压、拉拔和锻造等 )可以细化晶粒 (微米量级 )。纳米结构金属由于具有很小的晶粒尺寸 (2 0～ 5 0 0nm)和独特的缺陷结构 ,从而表现出优异的物理 力学性能。大塑性变形 (SPD)具有将铸态粗晶金属的晶粒细化到纳米量级的巨大潜力 ,近年来已引起人们的极大关注。介绍了 4种大塑性变形制备纳米结构金属的方法、原理、变形特点及应用 ,分析了纳米结构金属的强度和超塑性变形特征 ,以及当前研究中存在的主要问题 ,并对大塑性变形技术的应用前景进行了展望。更多还原

【Abstract】 Grain refinement may be used to improve the performances of materials. It is well known that heavy deformation, for example, by cold rolling, extrusion, drawing or forging, can result in significant microstructure refinement at low temperature. Nanostructured metals with mean grain sizes from 20～500 nm and specific defect structures have special physicao mechanical properties. Severe plastic deformation (SPD) is an effective route to refining coarse grain size into submicrometer or nanometer regime, which has attracted attention of many scientists all over the world. Several methods, principle of SPD for nanostructured metals were presented. Strength and superplasticity behaviors of nanostructured metals were also described. Present problems, further improvements and applications of SPD were put forward.更多还原