Modeling of a Sintering Process at Various Scales

Rojek, Jerzy; Nosewicz, Szymon; Maździarz, Marcin; Kowalczyk, Piotr; Wawrzyk, Krzysztof; Lumelskyj, Dmytro

doi:10.1016/j.proeng.2017.02.210

Cited by 42 publications

(32 citation statements)

References 13 publications

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“…Sintering is the consolidation of loose or weakly bonded powders with or without pressure at high temperatures which are close to their melting points. 17 During sintering, hard particulates pin dislocations in the matrix, thus restricting their movement, which improves the hardness of the matrix material through grain refinement. Yin et al reported such grain refinement and consequent improvement in hardness in which case B 4 C was the matrix material that was reinforced with Ti 3 SiC 2 and Si particles via spark plasma sintering.…”

Section: Microhardness Measurement Resultsmentioning

confidence: 99%

Effect of B4C addition on the microstructure, hardness and dry-sliding-wear performance of AZ91 composites produced with hot pressing

Öge¹,

Öge²,

Yılmaz³

et al. 2019

Mater. Tehnol.

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AZ91-B4C composites were fabricated with varying reinforcement ratios (5 w/%, 10 w/%, 20 w/% and 50 w/% B4C) via powder metallurgy and hot pressing to examine their microstructure, hardness and dry-sliding-wear performance. Powder compositions were verified with XRD and the microstructure of the sintered composites was evaluated using SEM (Scanning Electron Microscope) and EDS analyses. Hardness measurements and dry-sliding-wear tests were performed to evaluate the effect of reinforcement addition on the hardness and wear performance of the fabricated composites. Hot pressing of the composite with 50 w/% B4C required a significantly higher sintering pressure at the same sintering temperature. Increasing the B4C addition resulted in increased hardness values for all the composites, whereas the lowest worn volume and coefficient of friction were obtained with 10 w/% B4C.

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Section: Microhardness Measurement Resultsmentioning

confidence: 99%

Effect of B4C addition on the microstructure, hardness and dry-sliding-wear performance of AZ91 composites produced with hot pressing

Öge¹,

Öge²,

Yılmaz³

et al. 2019

Mater. Tehnol.

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“…Particle‐level models can comprise the physical quantities calculated by the molecular dynamics models within rate equations for the growth of sintering necks and the distance decrease between the approaching particles. The sintering particles can be described as spheres during the initial stage sintering and as tetrakaidecahedron shapes or similar regular geometric bodies that depend on the coordination number of the surrounding particles toward the final stage sintering . For obtaining realistic geometric shapes for particles with crystalline grains in particle‐level models, numerical tessellation methods (e.g., the Voronoi model) can be applied.…”

Section: Conversion Of Highly Filled Papers Into Paper‐derived Sintermentioning

confidence: 99%

“…Before DEM particle packing models were first developed, knowledge about the actual coordination number of the sintering particles within a green body stemmed from geometrical considerations, analytical physical models, or empirical test results. The most simplistic assumption, as stated first by Coble, was to consider agglomerations of idealized, equal‐sized particles as the closest packed spheres in a face centered cubic (FCC) or hexagonal closed‐packed (HCP) structure. Thus, a coordination number of 12 was assumed for a monomodal powder at the highest powder compact density, corresponding to 74.05% of the theoretical material density.…”

Section: Conversion Of Highly Filled Papers Into Paper‐derived Sintermentioning

confidence: 99%

Highly Filled Papers, on their Manufacturing, Processing, and Applications

et al. 2019

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Since more than a decade ago, the research on highly filled papers, as well as paper-derived inorganic materials, has greatly intensified. As presented in this review, highly filled papers as preforms allow for the design of porous or dense, multilayered, and geometrically complex structures. These paperderived ceramic-or metal-based materials are generated by the heattreatment of highly filled papers. Paper-derived materials are potential materials of choice for applications in transportation, energy-generation, environmental conservation, support structures, medical uses, and electronic components. Due to the adjustability of the filler content and the good machinability of highly filled papers, paper-derived sheets or multilayers may include intricate structures and tailored gradients in phase structure or porosity. Paper-derived multilayers also may contain cast ceramic tapes or other functionalized layers, as presented in some examples. Computer-aided manufacturing processes for paper-derived materials can be supplemented by prediction models for the sintering shrinkage in order to identify optimal post-processing steps, stacking orders and orientations for highly filled paper layers within multilayer green bodies. The accuracy of established component-level sintering models can be significantly increased by microstructure models of the highly filled paper. ParameterName Unit α Mismatch parameter for fiber cross-sections, Equation (5) Dimensionless α p Layer position in viscoelastic paper structure model, Equation (2) Dimensionless A 0 Initial amplitude of perturbation, Equations (15) 10 À6 m A(f) Parameter for evolution of instantaneous carbon conversion rate, Equation (7) Dimensionless A diff Source controlled diffusion parameter, Equations (9) 10 À7 N A match Modeling parameter, Equations (8) Dimensionless a Inter-particle contact-area radius, Equations (19) 10 À8 m a Local average pore area, Equation (4) 10 À6 m 2 b Pore geometry constant, Equation (20) Dimensionless ß evo , m evo Empirical constants for grain evolution in SOVS model, Equation (8) Dimensionless ß r(c)p Proportionality constant for bimodal packing fraction determination, Equation (18) Dimensionless C Modeling constant for debindering pressure calculation, Equation (7) 10 À6 (m 2 Á s)/K C 1 , C 2 , C 3 , C 4 , C 5 Parameters in the Riedel model that are determined by the dihedral angle, Equations (9) Dimensionless c glue Heat capacity of the adhesive layers, Equation (3) 10 À6 s c L , c s Volume fraction of larger-sized/smaller-sized particles in a multimodal mixture of particles, Equation (17)and (18) 10 0 vol% c vol Volume concentration of pulp fibers, Equation (4) 10 0 vol% γ, γ 0 Strain relaxation rate of calendered paper with initial value, Equation (2) Dimensionless γ B Grain boundary energy density, Equation (13) 10 0 J m À2 γ b Specific energy for grain boundary diffusion, Equation (9) 10 3 J mol À1 γ S Material surface energy, Equation (8, 11, and 13) 10 0 J m À2 Δ Half of the inter-particle boundary thickness, Equation (19) 10 À8...

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“…Major process parameters in all types of granulators are the liquid volume [8,25,28], granulator size, rotation speed, inclination angle [30][31][32] and filling rate [33]. The agglomeration process often needs to be optimized by playing with all these parameters in order to produce granules of high density, homogeneous distribution of primary particles, a targeted mean size and high strength [34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Agglomeration of wet particles in dense granular flows

Nezamabadi

Mutabaruka

et al. 2019

Eur. Phys. J. E

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In order to get insight into the wet agglomeration process, we numerically investigate the growth of a single granule inside a dense flow of an initially homogeneous distribution of wet and dry particles. The simulations are performed by means of the discrete element method and the binding liquid is assumed to be transported by the wet particles, which interact via capillary and viscous force laws. The granule size is found to be an exponential function of time, reflecting the conservation of the amount of liquid and the decrease of the number of available wet particles inside the flow during agglomeration. We analyze this behavior in terms of the accretion and erosion rates of wet particles for a range of different values of material parameters such as mean particle size, size polydispersity, friction coefficient and liquid viscosity. In particular, we propose a phase diagram of the granule growth as a function of the mean primary particle diameter and particle size span, which separates the parametric domain in which the granule grows from the domain in which the granule does not survive.

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Modeling of a Sintering Process at Various Scales

Cited by 42 publications

References 13 publications

Effect of B4C addition on the microstructure, hardness and dry-sliding-wear performance of AZ91 composites produced with hot pressing

Effect of B4C addition on the microstructure, hardness and dry-sliding-wear performance of AZ91 composites produced with hot pressing

Highly Filled Papers, on their Manufacturing, Processing, and Applications

Agglomeration of wet particles in dense granular flows

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