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International Journal for Multiscale Computational Engineering

Impact factor: 0.768

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

International Journal for Multiscale Computational Engineering

DOI: 10.1615/IntJMultCompEng.v4.i4.30
pages 445-460

Effects of Shape and Size of Crystal Grains on the Strengths of Polycrystalline Metals

Kenjiro Terada
Department of civil Engineering, Tohoku University, Sendai 980-8579, Japan
Ikumu Watanabe
Department of Civil Engineering, Tohoku University, Aza-Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
Masayoshi Akiyama
Corporate R&D Laboratories, Sumitomo Metal Industries Ltd., Fuso-cho 1-8, Amagasaki, Hyogo 660-0891, Japan

ABSTRACT

We investigate the effects of shape and size of crystal grains on the yielding behavior of polycrystalline metals by applying the two-scale finite element method, which is based on the homogenization theory combined with the constitutive models in crystal plasticity. After introducing the formulation of crystal-plasticity-based two-scale modeling, we characterize the mechanical behavior of a single crystal grain. Then, we first examine the effect of grain shape on macroscopic strengths by carrying out numerical experiments on several patterns of grain shapes and inhomogeneities of grain size distribution. Next, we explore the dependency of the various macroscopic strengths on the grain size, which are evaluated as the average behavior of aggregate representative volume elements (RVEs) or microstructures. We are here concerned with the empirical Hall-Petch relationship and intend to assess its possible sources for it apart from intergranular deformations.