The mesostructure—properties linkage in polycrystals

Adams, Brent L.; Olson, Tamara

doi:10.1016/s0079-6425(98)00002-4

Cited by 122 publications

(71 citation statements)

References 75 publications

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“…The upper bound of eff for a bulk, macroscopically isotropic material is known to be identical to that given in Eq. ͑11͒, 18,19 The practical self assembled structures of interest in this work 13 are considerably more random and less hierarchical than those proposed to realize eff,bulk,LB ͑Ref. 20͒ and eff,bulk,UB , 19 so it is reasonable to expect that neither bound will be a good approximation for the eff,bulk of interest, especially when r deviates significantly from unity.…”

Section: Averaging Rule For Nanobulkmentioning

confidence: 96%

“…17,18 Most work has focused on determining the theoretical upper and lower bounds of the effective conductivity, especially for configurations where the sample is macroscopically isotropic ͑obvi-ously leading to K eff = eff I, where I is the identity tensor͒. The upper bound of eff for a bulk, macroscopically isotropic material is known to be identical to that given in Eq.…”

Section: Averaging Rule For Nanobulkmentioning

confidence: 99%

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Effective thermal conductivity of polycrystalline materials with randomly oriented superlattice grains

Yang

Ikeda

Snyder

et al. 2010

Journal of Applied Physics

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A model has been established for the effective thermal conductivity of a bulk polycrystal made of randomly oriented superlattice grains with anisotropic thermal conductivity. The in-plane and cross-plane thermal conductivities of each superlattice grain are combined using an analytical averaging rule that is verified using finite element methods. The superlattice conductivities are calculated using frequency dependent solutions of the Boltzmann transport equation, which capture greater thermal conductivity reductions as compared to the simpler gray medium approximation. The model is applied to a PbTe/ Sb 2 Te 3 nanobulk material to investigate the effects of period, specularity, and temperature. The calculations show that the effective thermal conductivity of the polycrystal is most sensitive to the in-plane conductivity of each superlattice grain, which is generally four to five times larger than the cross-plane conductivity of a grain. The model is compared to experimental measurements of the same system for periods ranging from 287 to 1590 nm and temperatures from 300 to 500 K. The comparison suggests that the effective specularity increases with increasing annealing temperature and shows that these samples are in a mixed regime where both Umklapp and boundary scattering are important.

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Section: Averaging Rule For Nanobulkmentioning

confidence: 96%

Section: Averaging Rule For Nanobulkmentioning

confidence: 99%

Effective thermal conductivity of polycrystalline materials with randomly oriented superlattice grains

Yang

Ikeda

Snyder

et al. 2010

Journal of Applied Physics

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“…Polycrystalline materials (metals, alloys or ceramics) are commonly used in the engineering practice. 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].…”

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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“…Polycrystalline materials (metals, alloys or ceramics) are commonly used in engineering applications. Their microstructure, at the grain scale, is characterized by the grain 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 also have a direct effect on the initiation and evolution of damage. The behavior of polycrystalline materials at the microscale can be studied using experimental 7,8,9,10,11,12,13,14,15 and computational techniques 4,16,17 .…”

Section: Introductionmentioning

confidence: 99%

Modelling Polycrystalline Materials: An Overview of Three-Dimensional Grain-Scale Mechanical Models

Benedetti

Barbe

2013

J. Multiscale Modelling

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A survey of recent contributions on three-dimensional grain-scale mechanical modelling of polycrystalline materials is given in this work. The analysis of material microstructures requires the generation of reliable micro-morphologies and affordable computational meshes as well as the description of the mechanical behavior of the elementary constituents and their interactions. The polycrystalline microstructure is characterized by the topology, morphology and crystallographic orientations of the individual grains and by the grain interfaces and microstructural defects, within the bulk grains and at the inter-granular interfaces. Their analysis has been until recently restricted to twodimensional cases, due to high computational requirements. In the last decade, however, the wider affordability of increased computational capability has promoted the development of fully three-dimensional models. In this work, different aspects involved in the grain-scale analysis of polycrystalline materials are considered. Different techniques for generating artificial micro-structures, ranging from highly idealized to experimentally based high-fidelity representations, are briefly reviewed. Structured and unstructured meshes are discussed. The main strategies for constitutive modelling of individual bulk grains and inter-granular interfaces are introduced. Some attention has also been devoted to three-dimensional multiscale approaches and some established and emerging applications have been discussed.

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The mesostructure—properties linkage in polycrystals

Cited by 122 publications

References 75 publications

Effective thermal conductivity of polycrystalline materials with randomly oriented superlattice grains

Effective thermal conductivity of polycrystalline materials with randomly oriented superlattice grains

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

Modelling Polycrystalline Materials: An Overview of Three-Dimensional Grain-Scale Mechanical Models

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