Sintering forces acting among particles during sintering by grain‐boundary/surface diffusion

Abstract

The microstructural evolution during sintering involves the formation and pinchoff of pore channels. The sintering of 3 particles in 3 dimensions is a simple model for studying the pinch-off of a pore channel. We simulate the solid-state sintering of 3 particles by using Brakke's Surface Evolver program, which incorporates coupled grain-boundary diffusion and surface diffusion. The pinch-off of pore channel divides the sintering process into 2 stages; the initial stage and the later stage. The contact area has a noncircular shape bounded by both surface triple junction and triple junction in the later stage. A general method is presented to determine the sintering force acting on the noncircular contact. The mechanical approach of densification, where the relative motion of particles is driven by both sintering force and applied force, is applicable not only for the initial stage, but also for the later stage. K E Y W O R D Smicromechanical modeling, simulation, sintering

Analysis of the Electroconsolidation Process of Fine-Dispersed Structures Out of Hot Pressed Al2O3–WC Nanopowders

“…Figure 2 illustrates increasing contact between the particles during the sintering process. According to Wakai et al [29], the grain-boundary diffusion is driven by stress distribution or tension at the neck surface in the contact area. Thus, it is dependent on the dimensions of the particles and on compression at the center of the contact, as follows:…”

Microstructure evolution during sintering: discrete element method approach

“…A wide range of methods with varying spatial resolution has been investigated: molecular dynamics, 12,13 kinetic Monte Carlo methods, 14,15 phase field models, 16–18 and the models by Wakai et al. based on the surface evolver 19–22 . These methods advanced the understanding of sintering on a microscopic scale and can provide a reference for mesoscopic models.…”

“…methods, 14,15 phase field models, [16][17][18] and the models by Wakai et al based on the surface evolver. [19][20][21][22] These methods advanced the understanding of sintering on a microscopic scale and can provide a reference for mesoscopic models. However, they cannot predict the microstructure evolution of a sample, because the number of particles and the system size are either limited by the model itself or by computational cost.…”

A New Approach for Sintering Simulation of Irregularly Shaped Powder Particles—Part II: Statistical Powder Modeling

“…Cluster generation is a common problem in sintering simulation at microscopic scale. The main part of models found in the literature are working with handcrafted clusters of two or a few particles, especially the older ones like Geguzin, [ 4 ] Exner, [ 5 ] Svoboda and Riedel, [ 7 ] Bouvard and McMeeking, [ 8 ] Jagota and Dawson, [ 13 ] and Tikare et al, [ 28 ] but also in newer times like Wakai et al, [ 35 ] Biswas et al, [ 25 ] Chockalingam et al, [ 23 ] Léchelle et al, [ 12 ] Zhang et al, [ 22 ] and Shinagawa. [ 21 ] Random sphere packing is the second common approach, either by use of Voronoi cells like Arzt, [ 6 ] by gravity based models like Nikolic, [ 36 ] Nikolic and Shinagawa, [ 37 ] and Wang and Atkinson, [ 38 ] or by repulsion forces like Henrich et al [ 39 ] and Martin et al [ 40 ] The cited publications work either with equally sized spherical particles or with randomly generated spherical particles.…”