Effects of the Thermal Expansion Coefficient on the Cooling Process of the Fused Zirconia-Alumina Material

The solidification process simulation of the fused cast AZS material to predict porosity and cavity has not been extensively researched. Using software Any-casting, effects of the thermal expansion coefficient on solidification sequence, solidification percentage, solidification time, difference of temperature gradients, probabilities of macro-defects and micro-defects were studied. The results showed that: the thermal expansion coefficient less than 19.2E-06K -1 at 250℃ generated a bottom-up solidification sequence, which was conducive to the feeding capacity of riser; When the thermal expansion coefficient was less than 27.2E-06K -1 , solidification percentage at the bottom center of riser was larger than that at the center of cast; Considering solidification time, the thermal expansion coefficient should be less than 27.2E-06K -1 ; According to Niyama criterion, the probability of shrinkage cavity and its area in AZS casting were small when the thermal expansion coefficient was less than 19.2E-06K -1 . So the preferred thermal expansion coefficient of AZS material should be less than 19.2E-06K -1 . Keywords-AZS; the thermal expansion coefficient; solidification sequence; solidification percentage; shrinkage prediction