Activation volume for inelastic deformation in polycrystalline Ag thin films

被引：75

作者：

Kobrinsky, MJ ^{[1
]}

Thompson, CV ^{[1
]}

机构：

[1] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA

来源：

ACTA MATERIALIA | 2000年 / 48卷 / 03期

基金：

美国国家科学基金会;

关键词：

thin films; metals; mechanical properties (plastic); thermally activated processes; dislocations;

D O I：

10.1016/S1359-6454(99)00403-6

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The low temperature (T < 100 degrees C) inelasticity of polycrystalline Ag thin films on oxidized Si substrates has been studied, and the results are expected to be representative of other metallic thin films (e.g. Cu and Au) on rigid substrates. Values of the activation volume for inelastic deformations have been obtained by measuring the rates of stress relaxation during isothermal annealing of films. In situ Transmission Electron Microscopy was used to study the characteristics of dislocation motion in films deposited on micromachined Si membranes. The values of the activation volume and the presence of jerky glide indicate thermally activated motion of dislocations through forest-dislocation obstacles. The mean distance between obstacles along the length of moving dislocations was found to be significantly smaller than the thickness of the film and the grain size, which explains why current models for dislocation-glide-mediated plasticity underestimate the strength of thin films. (C) 2000 Acta Metallurgica me. Published by Elsevier Science Ltd. All rights reserved.

引用

页码：625 / 633

页数：9

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