Strength Properties of Sintered Alumina in Relation to Porosity and Grain Size

The strength properties of sintered alumina rods, as determined by modulus of rupture experiments, were measured for the purpose of finding the influence of grain size on strength. Sintering temperatures below and above the recrystallization temperature region were utilized in the fabrication of sintered alumina rods so that a wide variation of grain sizes could be tested. Porosity, measured as bulk density, had the largest influence on the moduli of rupture. No prominent change in strength could be observed as a result of recrystallization, but a minor decrease in strength could be attributed to an increase in void size or an increase in grain size.