非晶合金原子结构与变形行为本征关系的研究

项目名称： 非晶合金原子结构与变形行为本征关系的研究

项目编号： No.51271113

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： 陈明伟

作者单位： 上海交通大学

项目金额： 90万元

中文摘要： 不同于传统的金属材料，非晶合金缺少晶界、位错等微观层次的结构特征。其本征性能一般直接由原子尺度的结构及物理化学特性所决定。尽管近年来非晶合金短程原子结构的研究已取得了显著的进展，非晶合金变形行为和原子结构之间的相关性仍然是非晶领域最具挑战性的前沿问题之一。本项目围绕非晶合金原子结构特征和力学行为关系这个核心科学问题，通过跨尺度的实验方法研究非晶合金形变形微观机制及其与原子结构的相关性。拟采用埃尺度相干扫描电子衍射方法来表征非晶合金从短程有序到长程无序的结构演化；用动态原子力显微镜测定不同温度下非晶合金的粘弹性来表征流变单元，探讨流变单元与非晶局部原子结构的相关性；通过纳米压痕、原位应变透射电镜方法测量剪切带形核扩展动力学，从而建立原子结构、流变单元及与微观剪切带之间多层次的本征关系，确立基于实验原子结构的跨尺度的非晶形变微观机制，为设计、优化非晶材料的力学性能提供关键的指导作用。

中文关键词： 非晶合金；埃尺度相干扫描电子衍射；原子结构；二级弛豫；剪切带

英文摘要： Unlike crystalline metals and alloys, metallic glasses lack microscopic structure features and their physical and mechanical properties are usually determined by the local atomic structure. More recently, considerable progress has been made in the experimental characterization and theoretical modeling of the short-range atomic structure of metallic glasses. However, the structural evolution from short-range order (SRO) to long-range disorder (LRD) as well as the atomic structure of metallic glasses beyond short- and medium-range order is still poorly unknown, leading to that the correlation between atomic structure and mechanical properties of metallic glasses remains to be one of the most challenged questions in metallic glass research. In the proposed research, multi-scale experimental approaches will be employed to investigate the micromechanisms of plastic deformation of metallic glasses. A scanning coherent angstrom electron diffraction technique will be developed to characterize the long-range disordered atomic structure of metallic glasses. In order to understand the structural origin of shear transformation zones (STZs, i.e. deformation unit), the size and morphology of STZs in various metallic glassed will be characterized by measuring the inhomogeneity of viscoelasticity by dynamic force microscopy. Th

英文关键词： Amorphous Alloys；Angstrom Beam Electron Diffraction；Atomic Structure；β relaxation；Shear Band