Absolute Evaluation of Mechanical Properties of Thin Films Based on the Microplasticity Theory of Internal Friciton.

基于内摩擦微塑性理论的薄膜力学性能的绝对评价。

基本信息

批准号：
05650617
负责人：
NISHINO Yoichi
金额：
$ 1.41万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

Internal friction in aluminum thin films 0.2 to 2.0mum thick on silicon substrates has been investigated between 180 and 360 K as a function of strain amplitude by means of a free-decay method of flexural vibraion. According to the constitutive equation, the internal friction in the film alone can be evaluated separately from the data on the film-substrate composite. The amplitude-dependent internal friction in aluminum films is found in the strain range approximately two orders of magnitude higher than that for bulk aluminum. On the basis of the microplasticity theory, the amplitude-dependent internal friction can be converted into the plastic strain as a function of effective stress on dislocation motion. The mechanical responses thus obtained for aluminum films show that the plastic strain of the order of 10^<-9> increases nonlinearly with increasing stress. These curves tend to shift to a higher stress with decreasing film thickness and also with decreasing temperature, both indicating a suppression of the microplastic deformation. At all temperatures examined, the microflow stress at a constant level of the plastic strain varies inversely with the film thickness, which qualitatively agrees with the variation in the macroscopic yield strengths. From a practical standpoint, the present analytical approach of internal friction is applicable for non-destructive evaluation of stree-strain responses in thin films bonded to a substrate, and is directly comparable with uniaxial tensile testing of free-standing films detached from a substrate.

铝薄膜中的内部摩擦在硅底物上的厚度为0.2至2.0MUM厚的厚度为180至360 K之间，这是菌株振幅的函数，通过弯曲的自由弯曲方法的函数。根据本构方程，仅膜中的内部摩擦就可以与薄膜底物复合材料的数据分开评估。在应变范围内发现了铝膜中振幅依赖性的内部摩擦，大约比大铝高两个数量级。在微塑性理论的基础上，可以将振幅依赖性的内部摩擦转换为塑性应变，这是有效压力脱位运动的函数。因此，对铝制膜获得的机械响应表明，随着应力的增加，10^<-9>的塑性应变非线性增加。这些曲线倾向于随着膜厚度的降低以及温度降低而转移到更高的应力，这均表明抑制了微塑性变形。在所有检查的温度下，塑性应变水平的微流应力与膜厚度呈反变化，这与宏观屈服强度的变化质量一致。从实际的角度来看，目前的内部摩擦分析方法适用于对粘合到底物的薄膜中的链材响应的非破坏性评估，并且与从底物脱离的独立膜的单轴拉伸测试直接可比。