Driving force evolution in solid-state sintering with coupling multiphysical fields

Abstract

A phase field model based on coupled thermo–mechano–diffusional equations is presented to simulate the microstructure evolution of hot pressing sintering under nonisothermal conditions. Simulation results for different heating rates are basically consistent with the experimental densification curves. Further research shows that the temperature gradient driving force increases with the heating rates, whereas the driving force of concentration and strain gradients are the identical in the same shape (corresponding to a certain relative neck radius) with different heating rate. Moreover, Simulation results indicate the evolution trend of the concentration gradient driving force along with neck growth is consistent with that from the classical theory which derived using Fick's law in an ideal two-sphere equal-radius model. Finally, a dynamic equations of sintering driving force and neck growth rate are obtained under the assumption of constant temperature, and the dynamic equation of neck growth was proved to be valid in different phase field parameters and sintering temperatures.