ムライトセラミックスのクリープ変形速度に対する粒径の影響

抄録

The effect of grain size on creep in mullite ceramics containing 71, 72 and 74wt%Al₂O₃ (71A, 72A, and 74A, respectively) has been studied. It is shown that a glass phase existed around grain boundary triple points for 72A, whereas it did not exist for 74A from the observation by transmission electron microscope. Stress exponents n's for creep deformation were 1.1-1.2, 1.2-1.3 and 1.3-1.5, and grain size exponents m's were 2.4, 2.0 and 1.2 for 71A, 72A and 74A, respectively. It was assumed that the creep deformation was controlled by grain boundary sliding accommodated by cavitation for 74A, diffusion in glass phase at grain boundaries for 71A and their combined mechanism for 72A.