Grain Size/Microcracking Relations for Pseudobrookite Oxides

Grain size‐microcracking trends are examined in the three pseudobrookite oxides MgTi 2 O 5 , Fe 2 TiO 5 , and Al 2 TiO 5 . These trends are toward smaller critical grain sizes, lower elastic moduli, and lower strengths with increased thermal expansion anisotropy. Extension of an energy criterion relates the micro‐cracking transition to the inverse square of the maximum difference in single‐crystal thermal expansion coefficients, Δα max ‐2 .