Mechanical modelling of microwave sintering and experimental validation on an alumina powder

Microwave sintering (MW) allows fast heating (<= 30 min) and densification of ceramic materials, like alumina Al2O3. In order to predict the final material properties (density, size and grain size) the mechanical SOVS (Skorohold Olevsky Viscous Sintering) model is adapted and validated for conventional sintering of alumina. The model is implemented on ABAQUS with UMAT subroutine. Secondly, the SOVS model is modified for the microwave sintering by adapting the shear viscosity Arrhenius type law. Pre-exponential and exponential coefficients are modified for MW sintering. The calculated relative densities are compared to experimental results from conventional and microwave sintering and the relative difference remains under 3%. The coefficients identified for the MW sintering reveal a decrease in the shear viscosity by around 10 and an increase by up to 50 times in the grain boundaries diffusion coefficient.

Automated summary

The mechanical SOVS model is adapted to predict material properties during microwave sintering of ceramic materials, showing a decrease in shear viscosity and significant increase in grain boundaries diffusion coefficient in comparison to conventional sintering. The relative densities calculated from the model show good agreement with experimental results, with a relative difference of under 3%.