纳米多晶金属薄膜微结构及其演化与热激活机制的关联性研究

项目名称： 纳米多晶金属薄膜微结构及其演化与热激活机制的关联性研究

项目编号： No.51271141

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 王飞

作者单位： 西安交通大学

项目金额： 80万元

中文摘要： 金属晶体材料的塑性变形是一个热激活过程。因此，热激活参量的量化表征被广泛应用于纳米多晶金属力学性能的研究。然而，建立在粗晶金属变形行为基础之上的传统热激活理论并未考虑纳米多晶金属特有的微观结构及力学行为特征。因此，将传统热激活理论直接应用于纳米多晶金属塑性变形行为的研究方法是值得商榷的。基于此，针对面心立方纳米多晶金属薄膜，本项目在量化考察热激活参量在粗晶金属塑性变形中变化规律的传统方法基础上，通过预变形及低温热处理等方法构造并系统刻画纳米多晶金属中的若干特征微结构体系，尝试建立应变率敏感系数及热激活体积等热激活参量与纳米多晶金属特征微观结构的内在关联，研究方法具有较强的创新性和可操作性。从新的角度探讨传统热激活理论在纳米多晶金属特有微观结构体系下的适用性及评价方法，研究热激活参量在纳米多晶材料塑性变形中的物理意义。本项目的开展对热激活理论在块体纳米多晶金属的应用亦有重要借鉴意义。

中文关键词： 纳米多晶；力学性能；位错；晶界；热激活参量

英文摘要： Generally, plastic deformation in metallic materials could be considered as a thermally activated process. Therefore, quantitatively determination of thermal activated parameters, such as activation energy, activation volume and strain rate sensitivity, have been widely used to characterize the mechanical properties of nanocrystalline metals. However, the special microstructural features in nanocrystalline metals, which are quite different from their bulk counterparts, have not been considered as a crucial factor in conventional thermally activated thoery, which may affect characterizing mechanical properties significantly. Then, it might be some inadequate interpretations of the mechanical properties of nanocrystalline metals in using conventional thermally activated mechanism, which relies on the concepts of coarse grained metals. Therefore, the relevance of these concepts used in nanocrystalline metals must be questioned, considering the restricted mean free path of dislocations, and the extremely large volume of grain boundaries. Here, by focusing on several typical face-centered cubic nanocrystalline metal thin films, we try to establish and examine the characterizing microstructure in the nanocrystalline metals through pre-strain and low-temperature annealing; and try to establish the internal relevance be

英文关键词： Nanocrystalline；Mechanical Properties；Dislocation；Grain Boundary；Activation Parameters