Prediction of densification and microstructure evolution for α-Al2O3 during pressureless sintering at low heating rates based on the master sintering curve theory

The master sintering curve (MSC), in which the sintered density is a unique function of the integral of a temperature function over time, is insensitive to the heating path. Densification of ?-Al2O3 with the mean particle size of 2.5?m was continuously recorded during heating at 0.5, 2 and 5oC/min. A MSC was successfully constructed using dilatometry data with the help of a combined-stage sintering model. The validity of the MSC was verified by seveal experimental runs. The microstructural evolution with densification during different heating-rate sintering was explored. The sintered microstructure is a function of the time-temperature sintering conditions, and it is verified that there exists a link between sintered density and microstructure. The MSC can be used to predict and control microstructure evolution during sintering of ?-Al2O3 ceramics.