Young's modulus evolution during heating, re-sintering and cooling of partially sintered alumina ceramics

The Young modulus of partially and fully sintered alumina ceramics, obtained by firing to different temperatures (range 1200-1600 degrees C), has been determined via impulse excitation, and the evolution of Young's modulus of partially sintered alumina with temperature has been monitored from room temperature to 1600 degrees C. As expected, the room-temperature Young modulus of the partially sintered materials is lower than all theoretical predictions. With increasing temperature Young's modulus decreases, until the original firing temperature is exceeded and sintering (densification) continues, resulting in a steep Young's modulus increase. During heating and cooling the temperature dependence obeys a master curve for alumina, unless the temperature of the original firing is excessively low.