Micromechanical and macromechanical effects in grain scale polycrystal plasticity experimentation and simulation

By Dierk Raabe, M. Sachtleber, Z. Zhao, Franz Roters, S. Zaefferer. 2001

419 citations recorded by the source corpus.

A polycrystalline aluminum sample with a quasi-2D single layer of coarse grains is plastically deformed in a channel die plane strain set-up at ambient temperature and low strain rate. The microtexture of the specimen is determined by analysis of electron back scattering patterns obtained in a scanning electron microscope. The spatial distribution of the plastic microstrains at the sample surface is determined by measurement of the 3D plastic displacement field using a photogrametric pixel-based pattern recognition algorithm. The initial microtexture is mapped onto a finite element mesh. Continuum and crystal plasticity finite element simulations are conducted using boundary conditions which approximate those of the channel die experiments. The experimental and simulation data are analyzed with respect to macromechanical and micromechanical effects on grain-scale plastic heterogeneity. The most important contributions among these are the macroscopic strain profile (friction), the kinematic hardness of the crystals (individual orientation factors), the interaction with neighbor grain, and grain boundary effects. Crystallographic analysis of the data reveals two important points. First, the macroscopic plastic strain path is not completely altered by the crystallographic texture, but modulated following soft crystals and avoiding hard crystals. Second, grain- scale mechanisms are strongly superimposed by effects arising from the macroscopic profile of strain. The identification of genuine interaction mechanisms at this scale therefore requires procedures to filter out macro- scopically induced strain gradients. As an analysis tool, the paper introduces a micromechanicalTaylor factor, which differs from the macromechanical Taylor factor by the fact that crystal shear is normalized by the local rather than the global von Mises strain.  2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.

Subfields: Materials Chemistry, Mechanical Engineering, Mechanics of Materials

View Paper: https://www.semanticscholar.org/paper/a30937574b872bde1e896e7a072cca58ec2392bd

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Citations in the corpus

The role of heterogeneous deformation on damage nucleation at grain boundaries in single phase metals (2009, methodology): “Raabe et al. (2001) used a local micromechanical Taylor factor to better predict local crystal rotations and strains that were measured using high resolution strain mapping techniques.”
Effects of initial orientation, sample geometry and friction on anisotropy and crystallographic orientation changes in single crystal microcompression deformation: A crystal plasticity finite element study (2007, background): “for the case of single crystal deformation [8], bicrystal deformation [9–11], oligocrystal deformation [12] and nanoindentation [13,14].”
Simulation of micromechanical behavior of polycrystals: finite elements versus fast Fourier transforms (2009, methodology): “…extensively used for this purpose, both with regular (e.g. Becker (1991), Mika and Dawson (1999)) and Voronoi tessellated microstructures (Barbe et al 2001, Diard et al 2005), as also with EBSD based experimental data as input for simulations (e.g. Raabe et al (2001), Bhattacharyya et al (2001)).”
On the consideration of interactions between dislocations and grain boundaries in crystal plasticity finite element modeling – Theory, experiments, and simulations (2006, result): “The basic applicability of the crystal plasticity finite element approach to a large spectrum of intricate micromechanical problems has been shown by many studies in which both the textures and the strains were properly predicted when compared to corresponding experiments [4,8–13].”
Spectral TRIP enables ductile 1.1 GPa martensite (2016, methodology): “Uniaxial tensile tests with initial strain rate of 10 swere conducted for selected aging conditions combined with digital image correlation (DIC) using Aramis software (GOM GmbH) [36,37].”
DAMASK – The Düsseldorf Advanced Material Simulation Kit for modeling multi-physics crystal plasticity, thermal, and damage phenomena from the single crystal up to the component scale (2018, background): “[231], but it is also essential to reflect the correct boundary conditions in a simulation when matching experimental and simulated data oneto-one.”
Multiscale strain measurements of plastically deforming polycrystalline titanium: Role of deformation heterogeneities (2010, background): “Several finite element models have implemented experimental measurements of grain size and shape, and grain orientations to predict measured strain fields, see Delaire et al. (2000), Barbe et al. (2001), Raabe et al. (2001), Clayton et al. (2002), Crepin et al. (2007), and Zhao et al. (2008).”