Papers by Author: Zoran S. Nikolic

Abstract: This paper summarizes and reviews a number of important theoretical and experimental results connected to study of gravitational effects on liquid phase sintering. However, we will also investigate numerically gravity induced skeletal structure evolution during liquid phase sintering. Applying domain methodology, solid skeleton evolution will be introduced by definition of skeleton units determined by equilibrium dihedral angle and formation of large solid skeleton arranged in long chain of connected solid-phase domains. The settling procedure will be simulated by two submodels: free settling model in which solid-phase domains fall under gravity over already settled domains, and extended model in which settled domains continue their motion till they reach a position of their local equilibrium. Three more submodels will be also defined: rearrangement densification model, settling densification model, and Brownian motion model. It will be assumed that under gravity condition Stokes’s law settling usually dominates microstructure formation, where the settling procedure as well as settling time will be used for computation of average migration distance during defined time interval. Thus gravity induced solid-phase domain structure evolution will be simulated by simultaneous computation of displacement of the center of mass. The new methodology will be applied for simulation of microstructural evolution of a regular multi-domain model under gravity and gravity conditions.

Abstract: A finite difference method based on control volume methodology and interface-tracking technique for simulation of rapid solidification accompanied by melt undercooling will be described and applied to analyze the solidification of alumina sample on copper substrate.

Abstract: In this paper, we investigated numerically gravity induced skeletal settling during liquid phase sintering. The microstructural evolution will be simulated by simultaneous computation of displacement of the center of mass and mass transport due to dissolution and precipitation at the interfaces between solid-phase and liquid matrix. Common to this study based on domain methodology for definition of regular multi-domain model will be the need to relate some diffusional phenomena to essential geometric and topological attributes of the W-Ni porous microstructure influenced by skeletal settling combined with extrication of some solid-phase domains during liquid phase sintering.