Simulation of densification behavior of nano-powder in final sintering stage: Effect of pore-size distribution

In the final sintering stage, nano-sized powder frequently forms a pore structure where most pores are surrounded by more than 5 grains. The pore structure is different from that of coarse powder. In this study, the densification behavior of nano-sized powder is modelled and simulated in the final sintering stage. The porous body has the initial size distribution of pores, represented as a Weibull function. The mechanical interaction between pores is analyzed to simulate the evolution of porosity characteristics as well as densification kinetics. The densification rate for the size-distributed pores is lower than that for single-sized ones. The experimental relationship between the densification rate and the porosity could well be reproduced by choosing appropriate pore-size distributions. The simulation also shows that the sintering stress with densification may increase or decrease depending on the size distribution, but is remarkably lower than that for single-sized pores.

Automated summary

This study modeled and simulated the densification behavior of nano-sized powder in the final sintering stage, showing that the densification rate for size-distributed pores is lower than for single-sized ones. By choosing appropriate pore-size distributions, the experimental relationship between densification rate and porosity can be reproduced effectively. Additionally, the simulation revealed that the sintering stress with densification may increase or decrease depending on the pore size distribution, but is significantly lower than for single-sized pores.