【作者】 唐翠屏；

【导师】 周建忠；

【作者基本信息】 江苏大学 ， 机械电子工程， 2007， 硕士

【摘要】 膜基界面结合强度是表征薄膜质量的重要指标，是薄膜技术研究与应用中的关键技术。红外激光准静态划痕法是一种非接触测量硬质薄膜基体界面结合强度的新型检验方法。其原理是利用长脉冲激光准静态加载涂层试样的薄膜表面，引起薄膜与基体的脱粘和薄膜破坏，同时工件相对于激光做进给运动，用膜基界面破坏时的激光参数结合检测参数和膜基材料的物性参数来表征界面的结合强度。论文首先分析了激光划痕试验法表征薄膜涂层界面结合强度的原理、方法与过程。根据加载激光的工艺参数以及薄膜、基体的材料特性，基于傅立叶热传导方程，建立了薄膜与基体的有限元模型，得到膜基系统中温度场和应力场的计算公式。对固定激光源和移动激光源准静态加载薄膜表面后形成的温度场，分别进行了有限元模拟，获得膜基系统中温度随时间的变化关系以及薄膜界面结合处的热量化规律。在此基础上根据薄膜和基体的热膨胀性能，准静态条件下的热弹性本构方程、应变位移关系以及应力平衡关系，进行薄膜和基体的应力场模拟，获得了膜基系统的应力场随时间的变化关系以及关键点处的温度、应力曲线。根据线弹性断裂力学及弹塑性断裂理论，利用ANSYS有限元分析软件，选取膜基结合界面处应力较大的危险点作为裂尖单元，进行其强度因子及J积分的分析计算。结果表明：在激光加载过程中，薄膜和基体中的温度场随着时间的增加而增加，并在薄膜和基体之间产生温差。在膜基系统产生的应力场中薄膜上表面为压应力，膜基界面结合处产生的应力较大。随着激光能量密度的增加，应力强度因子增加，薄膜厚度增加时应力强度因子也增加。将模拟结果与实验结果进行对比，得到的薄膜和基体中应力场的理论计算结果和实验结果虽存在一定的误差，但定性地反映了薄膜和基体中温度和热应力的变化规律。研究结果为分析激光划痕法的作用过程提供了一定的理论依据，对研究膜基系统失效进程具有重要意义。更多还原

【Abstract】 Bonding strength of the interface of film-substratum is an important factor and key problem that influence the reliability and usage of film-substratum system. The new technology of laser scratching method which synthesizes the advantages of traditional scratching technique and laser measure technique has been performed by authors of the paper.Firstly,the principle, process and method are analyzed in this paper. According to the processing parameters and the material characters of the film and substratum, the model of film-substratum system is build. And using the principle of Fourier heat conduction and linear fracture theory, the temperature field and stress intensity of film-substrate system, are calculated theoretically.Secondly, material parameters changing with time are considered. Finite element model of film substratum system is build. The transient coupling process of laser loading is calculated in this paper, and the temperature field and stress field are obtained. In the process of laser loading, the temperature fields of film and substratum system are increased with time. The differences of material coefficients between film and substratum create thermal stress on the interface. Distribution of thermal stress is analyzed, and the angerous region of interface destroyed is given.Thirdly, a finite element simulation was processed to analyze the temperature, stress and stress intensity factor near the crack tip by using finite element analysis software ANSYS. Two dimensional calculations are produced for axisymmetic cylindrical cross-section. In order to model the analyzing process, laser source is assumed to load on the top centre of cylindrical and the crack is along the interface between film and substratum, the crack tip is created by nod release method. The bonding situation of interface is simulated using contact elements on the interface.The result illustrate that: the peak value of stress is in the center of laser facular, and the rebound of stress on the edge of facular also can cause the pure off of film. It provide theory support to laser scratch testing, it has great meaning on study film substratum invalidate process. The laser scratching method can be used to solve the interface crack problem by using thermally and mechanically induced stresses as the crack surface tractions.更多还原