【作者】 李春；

【导师】 杨平；

【作者基本信息】 江苏大学 ， 机械电子工程， 2010， 硕士

【摘要】 伴随着当今社会的快速发展,电气、电子装置等设备正逐步向着高性能、多功能、高速度方向发展,同时信息处理能力速度也在急速提高,这些必然要求系统向着大规模、大容量以及大型化方向发展。与此相对,在微机电系统中,却要求构成系统的装置、零部件、材料等具备轻、薄、短、小等方面的特点。金属纳米薄膜材料及其相关工艺便在这些需求下得到了飞速的发展,其中双层纳米金属薄膜由于在结构上与单层膜具有较大的差异,具备单层膜难以达到的一些性能,如提高硬度和摩擦磨损性能,改善涂层的韧性、抗裂纹扩展能力和热稳定性等,这些使得人们越来越关注其在纳米尺度下结构及其力学性能的研究。本文利用磁控溅射方法制备了Cu/Cr、Cr/Al、W/Cr、Al/Cr四组基于Cr膜配对的金属双层纳米薄膜,并对其进行了微结构以及力学性能测试的研究；在Cr/Al金属双层纳米薄膜压痕实验的基础上,应用有限元分析的方法对其进行了仿真研究。主要研究工作如下：1.利用纳米压痕实验测试研究了Cu/Cr、Cr/Al、W/Cr、Al/Cr四组金属双层纳米薄膜,得出了四组双层膜的弹性模量值和硬度值,并且根据弹性模量和硬度随着压深的不同而呈现出的变化趋势,研究了双层膜中膜-膜界面、膜-基界面的结构；并且对比了热循环载荷前后Cu/Cr、Al/Cr两组金属双层纳米薄膜的压痕测试结果,研究了热循环载荷对于双层膜力学性能的影响,发现对于Cu/Cr双层膜而言,经过热循环载荷后的弹性模量值和硬度值均高于热循环前。但是对于Al/Cr双层膜而言,却相反,即热循环载荷后的弹性模量值和硬度值均低于热循环前。2.利用纳米划痕实验测试研究了W/Cr、Cr/Al两组金属双层纳米薄膜,近似得出了双层膜中膜-膜界面、膜-基界面的界面结合力。并且对比了热循环载荷前后的划痕测试结果,分析了热循环载荷对双层膜中界面结合力的影响,发现热循环载荷降低了W/Cr双层膜中膜-膜界面以及膜-基界面处的结合力；但是热循环载荷却能够提高Cr/Al双层膜中膜-基界面处的结合力,从而使得Cr/Al双层膜中各组成膜间能够形成良好的界面结构。3.利用有限元仿真的方法,在Cr/Al金属双层纳米薄膜纳米压痕实验的基础上,对其进行数值模拟,发现最大应力集中在压头附近,并且应力主要集中在双层膜膜层内部,双层膜对衬底具有一定的保护作用；并且得出了双层膜中界面处和膜的表面处Y方向的应力随着x方向增加而减小,压头正下方Y方向的应力随着Y方向的增加而出现先缓慢增加后线性减小的趋势。更多还原

【Abstract】 With the rapid development of economy and society in the world, the electrical and electronic devices develop to a higher performance, multi-function, higher speed and the information processing ability is improved quickly. All of these must continue the equipment system towards large-scale, large capacity and maximization directions. But, on the other hand, the units, parts and the materials of the system must be designed to light weight, thin structure, short calculating period, small volume and many other characteristics. To meet these requirements, the materials and process of metal nanometer films develop quickly. Among them, the bilayer films which structure is different from the single film have many nice properties. There are higher hardness, friction and wear properties in the bilayer films. And even more, they can improve the toughness, resistance to crack extension and thermal stability of the coating. So, more and more researchers study of the structure and mechanical properties of the bilayer films at the nanometer scale.In this paper, Cu/Cr bilayer films, Cr/Al bilayer films, W/Cr bilayer films and Al/Cr bilayer films are prepared by using the magnetron sputtering. And their microstructure and mechanical properties are also studied. Based on the nano-indenter experiment of Cr/Al bilayer films, the finite element analysis is used to simulate the experiment. Totally, the following parts are investigated:1. Cu/Cr bilayer films, Cr/Al bilayer films, W/Cr bilayer films and Al/Cr bilayer films are studied in the nano-indenter experiment. Their elastic modulus value and hardness value are obtained from the experiment. Test results show that the elastic modulus and hardness of the bilayer films vary with the indent depth in accordance to a certain rule. The structure of the interface in the films and between the films and the substrate are studied according to the rule. Effects of the thermal cycling on the mechanical properties of the Cu/Cr bilayer films and the Al/Cr bilayer films are also studied. To the Cu/Cr bilayer films, the elastic modulus value and the hardness value are higher after the thermal cycling. But the effect is opposite to the Al/Cr bilayer films.2. W/Cr bilayer films and Cr/A1 bilayer films are studied in the nano-indenter experiment. The interfacial binding forces in the films and between the films and the substrate are obtained. Compared to the test results in the nano-scratch before and after the thermal cycling, the interfacial binding forces in W/Cr bilayer films can be decreased. But the interfacial binding forces in Cr/A1 bilayer films can be improved after the thermal cycling which can form a nice interface structure between each composition film.3. Based on the nano-indenter experiment of Cr/Al bilayer films, FEA method is used to simulate the experiment. It can be known that the maximum stress is mainly centralized nearby the indenter. And the stress is mainly centralized in the bilayer films which will protect the substrate. From the simulation, the stress value in the Y direction in the interface and on the surface of the bilayer films is becoming smaller when the distance in the X direction is far away from the indenter. And the stress value in the Y direction below the indenter increases slowly at first and decreases linearly later when the distance in the Y direction increases.更多还原