Mini-symposium title 

1-6 – Multiscale Modelling of Polycrystalline Materials  

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Organisers 

Javier Segurado (Universidad Politécnica de Madrid), Ricardo A. Lebensohn (Los Alamos National Laboratory) 

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Mini-symposium description 

The mechanical response of polycrystalline materials depends on single crystal behaviour and microstructure. At single crystal level, deformation is controlled by anisotropic crystal elasticity, dislocation nucleation, motion and interactions, and other mechanisms like the formation and evolution of twins, phase transformations, diffusion-driven deformation, etc. Plastic deformation of crystalline materials can be modelled at different scales using atomistic/discrete approaches (molecular dynamics) or continuum formulations (dislocation dynamics, crystal plasticity). Microstructure has a deep influence in the macroscopic response of polycrystalline materials and can be described by the grain size, grain shape and crystallographic orientation distributions, character of the grain boundaries that control the interactions between adjacent grains, etc. A realistic, microstructure-based description of the polycrystal’s macroscopic behaviour needs to incorporate models for the deformation mechanisms at single crystal level, and integrate them to provide the macroscopic response, which usually involve the use of some kind of multiscale methodology. 

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This symposium focuses on recent advances in model and simulation techniques to predict microstructure-dependent mechanical properties of polycrystalline aggregates. The main topics are: 

 

• Physics-based constitutive behaviours for single crystals and grain boundaries, with explicit consideration of dislocation densities, dislocation interactions, vacancy-mediated deformation mechanisms and temperature-dependence.   

• Semi-analytical models representing microstructure-sensitive properties of polycrystals: elastic plastic anisotropy, tension-compression asymmetry, complex (e.g. anisotropic, kinematic) hardening behavior, dilatational plasticity due to the presence of voids, etc. 

• Mean-field/homogenization-based crystal plasticity models to represent the micromechanical response of polycrystalline materials, including the aforementioned microstructural effects. 

• Full-field/computational homogenization models for polycrystals: crystal plasticity FEM, Fast Fourier Transforms (FFT)-based methods, including higher-order plasticity theories. 

• Discrete dislocation dynamics, including treatment of single-crystal elastic anisotropy and heterogeneity (polycrystallinity, grain boundaries, precipitates, free surfaces). 

• Hierarchical models for the multiscale modelling of polycrystals, including combination of the previous approaches.​

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