New opportunities for 3D materials science of polycrystalline materials at the micrometre lengthscale by combined use of X-ray diffraction and X-ray imaging

Ludwig, Wolfgang; King, Andrew; Reischig, P.; Herbig, Michael; Lauridsen, E.M.; Schmidt, Søren; Proudhon, Henry; Forest, Samuel; Cloetens, Peter; Roscoat, Sabine Rolland Du; Buffière, Jean‐Yves; Marrow, James; Poulsen, Henning Friis

doi:10.1016/j.msea.2009.04.009

Cited by 170 publications

(90 citation statements)

References 38 publications

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“…grain shape and orientations, would give a better reference for the comparison with the crystal plasticity model. Such experimental data could be obtained using 3D synchrotron imaging techniques like Absorption Contrast Tomography and Diffraction Contrast Tomography (DCT) [24,25]. Polycrystal samples made of a few hundred to a few thousand grains can be reconstructed into a voxelated volume and then converted into a mesh ready for Finite Element computations.…”

Section: Materials Parameters Identificationmentioning

confidence: 99%

Numerical investigations of the free surface effect in three-dimensional polycrystalline aggregates

Guilhem

Basseville

Curtit³

et al. 2013

Computational Materials Science

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The aim of the present paper is to investigate the consequences of the loading on the free surface response in polycrystalline aggregates. The study is made on a 316L stainless steel. Finite element computations using a crystal plasticity model are performed to simulate a polycrystalline aggregate submitted to different cyclic loadings. A statistical analysis of the results is carried out to extract information concerning the local stress and local strain fields at the free surface. The analysis of plastic strain localization on surface maps and inside the bulk through transparent volumetric views allows to exhibit the effects of the grain orientation and of the loading on local mechanical fields. The computation of an indicator characterizing extrusion/intrusion steps give some information on the initiation sites.

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Section: Materials Parameters Identificationmentioning

confidence: 99%

Numerical investigations of the free surface effect in three-dimensional polycrystalline aggregates

Guilhem

Basseville

Curtit³

et al. 2013

Computational Materials Science

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“…Moreover, given the parameters α and β and the ratio G II /G I , δu cr s can be inferred from Eqs. (30), that hold general validity. Assuming a coordinate reference system centered at the center of symmetry of the specimen, and with the axes aligned with the specimen edges, as shown in Fig.…”

mentioning

confidence: 93%

A three-dimensional cohesive-frictional grain-boundary micromechanical model for intergranular degradation and failure in polycrystalline materials

Benedetti

Aliabadi

2013

Computer Methods in Applied Mechanics and Engineering

116

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In this study, a novel three-dimensional micro-mechanical crystal-level model for the analysis of intergranular degradation and failure in polycrystalline materials is presented. The polycrystalline microstructures are generated as Voronoi tessellations, that are able to retain the main statistical features of polycrystalline aggregates. The formulation is based on a grain-boundary integral representation of the elastic problem for the aggregate crystals, that are modeled as threedimensional anisotropic elastic domains with random orientation in the three-dimensional space. The boundary integral representation involves only intergranular variables, namely interface displacement discontinuities and interface tractions, that play an important role in the micromechanics of polycrystals. The integrity of the aggregate is restored by enforcing suitable interface conditions, at the interface between adjacent grains. The onset and evolution of damage at the grain boundaries is modeled using an extrinsic non-potential irreversible cohesive linear law, able to address mixed-mode failure conditions. The derivation of the traction-separation law and its relation with potential-based laws is discussed. Upon interface failure, a non-linear frictional contact analysis is used, to address separation, sliding or sticking between micro-crack surfaces. To avoid a sudden transition between cohesive and contact laws, when interface failure happens under compressive loading conditions, the concept of cohesive-frictional law is introduced, to model the smooth onset of friction during the mode II decohesion process. The incrementaliterative algorithm for tracking the degradation and micro-cracking evolution is presented and discussed. Several numerical tests on pseudo-and fully three-dimensional polycrystalline microstructures have been performed. The influence of several intergranular parameters, such as cohesive strength, fracture toughness and friction, on the microcracking patterns and on the aggregate response of the polycrystals has been analyzed. The tests have demonstrated the capability of the formulation to track the nucleation, evolution and coalescence of multiple damage and cracks, under either tensile or compressive loads.

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“…Their microstructure, at the grain scale, is characterized by grains morphology, size distribution, anisotropy and crystallographic orientation, by the presence of flaws and porosity and by physical and chemical properties of the intergranular interfaces [6], which have direct influence on the initiation and evolution of damage. Polycrystalline microstructures have been studied using experimental [7,8,9,10,11,12,13,14,15] and computational techniques [4,16,17]. Much research has been carried out for developing numerical models for polycrystalline microstructures and their failure processes.…”

Section: Introductionmentioning

confidence: 99%

Multiscale modeling of polycrystalline materials: A boundary element approach to material degradation and fracture

Benedetti

Aliabadi

2015

Computer Methods in Applied Mechanics and Engineering

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In this work, a two-scale approach to degradation and failure in polycrystalline materials is proposed. The formulation involves the engineering component level (macro-scale) and the material grain level (micro-scale). The macro-continuum is modelled using a three-dimensional boundary element formulation in which the presence of damage is taken into account employing an initial stress approach for modelling the local softening in the neighborhood of points experiencing degradation at the micro-scale. The microscopic degradation is explicitly modelled by associating Representative Volume Elements (RVEs) to relevant points of the macro continuum, for representing the polycrystalline microstructure in the neighborhood of the selected points. A three-dimensional grain-boundary formulation is used to simulate intergranular degradation and failure in the microstructure, whose morphology is generated using Voronoi tessellations. Intergranular degradation and failure are modelled through cohesive and frictional contact laws. To couple the two scales, macro-strains are transferred to the RVE as periodic boundary conditions, while overall macro-stresses are obtained as volume averages of the micro-stress field. The comparison between effective macro-stresses for the damaged and undamaged RVE allows to define a macroscopic measure of material degradation. To avoid pathological damage localization at the macro-scale, integral non-local counterparts of the strains are employed. The multiscale processing algorithm is described. Some multiscale simulations are performed to investigate the capability of the method.

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New opportunities for 3D materials science of polycrystalline materials at the micrometre lengthscale by combined use of X-ray diffraction and X-ray imaging

Cited by 170 publications

References 38 publications

Numerical investigations of the free surface effect in three-dimensional polycrystalline aggregates

Numerical investigations of the free surface effect in three-dimensional polycrystalline aggregates

A three-dimensional cohesive-frictional grain-boundary micromechanical model for intergranular degradation and failure in polycrystalline materials

Multiscale modeling of polycrystalline materials: A boundary element approach to material degradation and fracture

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