EFFECT OF YTTRIUM AND LANTHANUM ON THE TENSILE CREEP-BEHAVIOR OF ALUMINUM-OXIDE

The tensile creep behavior of two rare-earth dopant systems, lanthanum - and yttrium-doped alumina, are compared and contrasted in order to b etter understand the role of oversized, isovalent cation dopants in de termining creep behavior. It was found that, despite some microstructu ral differences, these systems displayed qualitatively a similar impro vement in creep resistance, supporting the hypothesis that creep is st rongly influenced by segregation. Differences in primary creep behavio r and activation energy for steady-state creep were, however, observed for these systems. Given these results, it is expected that creep beh avior can be further optimized by adjusting the dopant level and by co ntrolling the microstructure.