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International Journal for Multiscale Computational Engineering
IF: 1.016 5-Year IF: 1.194 SJR: 0.554 SNIP: 0.68 CiteScore™: 1.18

ISSN Print: 1543-1649
ISSN Online: 1940-4352

International Journal for Multiscale Computational Engineering

DOI: 10.1615/IntJMultCompEng.2012003172
pages 45-57

MULTISCALE MICROMORPHIC MODEL FOR THE PLASTIC RESPONSE OF CU THIN FILM

Zhaohui Zhang
School of Aerospace, Tsinghua University
Zhuo Zhuang
Failure Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084
X. C. You
Failure Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
Z. L. Liu
Failure Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
J. F. Nie
Failure Mechanics Laboratory, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
Yuan Gao
Applied Mechanics Laboratory, School of Aerospace, Tsinghua University, Beijing 100084 China

ABSTRACT

In this article, the multiscale micromorphic plasticity model is employed to quantitatively investigate the size and Bauschinger effects of freestanding Cu thin films in a continuum sense. The simulations, including the single-layer and multi-layer models, are carried out within a two-dimensional plane strain framework with the passivation layer modeled as the higher-order boundary condition. The computational results are compared with the experimental data of two sets of films consisting of the electroplated and sputtered films. It is found that for the electroplated films, the effects of film thickness are in quite good consistent with the experimental data. The strengthening factor charactering the passivation effect agrees well with the experiments for both the electroplated and sputtered films. The boundary layers near the internal interfaces (grain boundaries or film-passivation layers) are captured. The accumulation of the backstress scales almost linearly with the pre-strain. In the multi-layer polycrystal model, the yield strength of electroplated films obeys a nonlinear dependence on grain boundary density.