Changes in the Grain Boundary Character and Energy Distributions Resulting from a Complexion Transition in Ca-Doped Yttria

The grain boundary character distribution and the relative grain boundary energy of 100 ppm Ca-doped yttria were measured before and after a previously identified grain boundary complexion transition. The grain boundary character distribution of samples exhibiting normal grain growth (before the complexion transition) favored {111} planes, whereas those exhibiting abnormal grain growth (after the complexion transition) favored {001} planes. Additionally, the relative grain boundary-to-surface energy ratios in the sample exhibiting abnormal grain growth were 33 pct lower than in the sample exhibiting normal grain growth. The results also indicate that the complexion transition increased the anisotropy of the grain boundary energy, and this may be responsible for the increase in the anisotropy of the grain boundary character distribution.