金属多层膜界面、相变及相关力学性能的实验与理论研究

项目名称： 金属多层膜界面、相变及相关力学性能的实验与理论研究

项目编号： No.50871057

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 赖文生

作者单位： 清华大学

项目金额： 36万元

中文摘要： 本项目采用分子动力学模拟和实验相结合，深入研究金属多层膜中的组元结构、晶胞参数、弹性模量差及生成热等因素对纳米多层膜力学性能的影响，着重研究生成热为正的系统中不同的界面结构（如非晶态，共格或非共格晶态界面等）对多层膜力学性能的影响规律。采用已建立的从原子作用势计算不同结构材料弹性常数的理论模型，用分子动力学模拟计算具有不同界面结构多层膜的弹性常数、界面能和界面应力，找出它们之间的相关性。用超高真空镀膜装置或离子束辅助沉积技术制备纳米多层膜，通过镀膜参数控制或固态界面反应获得不同的界面结构，并用高分辨截面电镜进行观察和纳米硬度计测量其硬度和杨氏模量。开展纳米硬度计中纳米压入过程的大规模分子动力学模拟，深入研究不同界面结构对多层膜硬度的影响机理。所获成果将有助于揭示多层膜中的超硬机理，为超硬薄膜的设计提供新的思路和理论指导。

中文关键词： 多层膜；界面；第一性原理计算；分子动力学模拟；力学性能

英文摘要： In this project, by combining molecular dynamics simulations with experiments, we will study the influence of constituent element parameters such as structure, lattice constant misfit, elastic modulus difference and heat of formation on the mechanical properties of metallic nano-multilayers, with an emphasis on the role of interface of the binary systems with positive heat of formation. Employing our proposed theoretical model for calculating the elastic constants of materials directly from interatomic potentials, molecular dynamics simulations are performed to study the correlation among the elastic constants, the interfacial energy and stress in the multilayers with different interfacial structures. The metallic multilayers are produced by an ultrahigh vacuum electron deposition or ion beam aided deposition technique, the elastic properties of the multilayers are measured by nano-indentation and the interfacial structures are investigated by a high resolution cross-section TEM. Large scale molecular dynamics simulations will be conducted to imitate the process of nano-indentation so as to identify the role of interfacial structures in the hardness of the multilayers. The results obtained in this project will be helpful to reveal the hardening mechanisms in the metallic multilayers, and thus provide a new idea or theoretical guide for the design of superhard films.

英文关键词： Multilayers; Interface; The first- principles calculation; Molecular dynamics simulation; Mechanical properties