Phase-field model of sintering
Sintering is an old phenomenon that is being in practice for thousands of years. Today we understand the overall mechanism of sintering. A number of sintering models have been proposed and developed in the literatures which uses analytical approaches based on mass transport, kinetic Monte-Carlo method, finite element analysis etc. and successfully described sintering of particle assemblies. However, still there are some unanswered basic questions regarding the mechanism of sintering.
Sintering is an old phenomenon that is being in practice for thousands of years. Today we understand the overall mechanism of sintering. A number of sintering models have been proposed and developed in the literatures which uses analytical approaches based on mass transport, kinetic Monte-Carlo method, finite element analysis etc. and successfully described sintering of particle assemblies. However, still there are some unanswered basic questions regarding the mechanism of sintering.
Most of the sintering model considers particles to be a single crystal but in reality, we find very few single crystal particles. In this work, we have built up a Phase-Field model to comprehend difference in sintering behaviour between the single crystal and polycrystalline particle assemblies.
Most of the sintering model considers particles to be a single crystal but in reality, we find very few single crystal particles. In this work, we have built up a Phase-Field model to comprehend difference in sintering behaviour between the single crystal and polycrystalline particle assemblies.
In our model, we have attempted to include the effect of vacancy creation and annihilation during sintering which was mostly ignored in most previous Phase-Field models. In this work, the case of particles having single crystal nature as well as particles having polycrystalline nature. We have taken particles of different sizes in two dimensions to find out how sintering rate and neck growth is influenced by particle crystallinity and sizes. We have also tried to study the effect of grain boundary mobility during sintering.
In our model, we have attempted to include the effect of vacancy creation and annihilation during sintering which was mostly ignored in most previous Phase-Field models. In this work, the case of particles having single crystal nature as well as particles having polycrystalline nature. We have taken particles of different sizes in two dimensions to find out how sintering rate and neck growth is influenced by particle crystallinity and sizes. We have also tried to study the effect of grain boundary mobility during sintering.
Our result show that for single crystalline particle neck growth is very fast initially then it stagnates. Thus matches well with the experimental observation in Ceria and Thoria particles. In our result, polycrystalline particles shows slower sintering rate than single crystalline particle due to the metastability of the pore as it is surrounded by more than critical number of grains. Faster grain boundary mobility leads to coarsening of the grains and reduces the number of grains surrounding the grains and in that case we observe shrinkage in pore and densification. In summary, our work show that crystallinity of the particles is an important factor which determines the final densification.
Our result show that for single crystalline particle neck growth is very fast initially then it stagnates. Thus matches well with the experimental observation in Ceria and Thoria particles. In our result, polycrystalline particles shows slower sintering rate than single crystalline particle due to the metastability of the pore as it is surrounded by more than critical number of grains. Faster grain boundary mobility leads to coarsening of the grains and reduces the number of grains surrounding the grains and in that case we observe shrinkage in pore and densification. In summary, our work show that crystallinity of the particles is an important factor which determines the final densification.
Polycrystal particle
Polycrystal particle
Single crystal particle
Single crystal particle