Mesoscale numerical simulation of microstructure evolution in liquid phase sintering
PAN Shiyan1，2，SHEN Xiaoping2，JIA Di3，WANG Jiahao1，FAN Cang4
（1. School of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094,
China; 2. Engineering Training Center, Nanjing University of Science and Technology, Nanjing 210094, China;
3. Nanjing Line Accessones Co., Ltd. of China Energy Engineering Group, Nanjing 211599, China; 4. Beijing
Ruili Material Science and Technology Center, Beijing 100041, China）
Abstract：Liquid phase sintering (LPS) is a key technology for forming multiple-phase components from metallic
powders. To improve the properties of LPS products, numerical simulation of the microstructure evolution during
LPS is performed to optimize the powder mixture ratio and sintering process. In this paper, several mesoscale methods
for numerical simulation of microstructure evolution during LPS are reviewed, and the great potential of CALculation
of PHAse Diagrams (CALPHAD) approach and diffusion kinetic method in the quantitative simulation of
LPS is shown. The mesoscopic numerical simulation of microstructure evolution during LPS can be carried out in
three overlapping stages respectively. The first stage involves rapid initial densification caused by the capillary forces
exerted by the liquid phase on the solid particles. The initial kinetics of the rearrangement stage is accelerated
by the dynamic wetting of metallic melts at high temperatures. Discrete element method, phase field method, and
viscous flow Navier-Stokes equations can be currently applied for simulating the formation of the liquid phase and
the rearrangement of particles during the first stage. In the second stage, the liquid allows densification by solution-reprecipitation of solid phase which generally involves Ostwald ripening. Monte Carlo method and phase field
method are usually used for simulating the dissolution and re-precipitation of solid phase. In the third stage, grain
growth continues while the solid skeleton sinters to full density. For simulating the formation of a skeleton structure,
phase field method might be a more comprehensive algorithm. Due to the complexity of the LPS system and
the limitation of different simulation methods, it is necessary to conduct a comprehensive numerical analysis of the
LPS process by coupling the different simulation approaches. Simulating the complete LPS process can be the
main development direction of numerical simulation of microstructure evolution for LPS process. The application
of CALPHAD method and diffusion kinetic method in the field of LPS microstructure evolution simulation is very
important for quantitative analysis. Monte Carlo method, discrete element method, and phase field method need to
accurately evaluate the chemical potentials and diffusion mobilities of atoms to achieve quantitative LPS microstructure
evolution simulation for multicomponent alloys. Therefore, coupling the mesoscale method with newlydeveloped
material thermodynamic and diffusion dynamic databases is also a recent important development direction
of quantitative modeling. of microstructure evolution for the LPS process.
2022, Vol. 32 
