In short: yes it can be and is/was used as ODS additive. There are also variants with YAlO3-mixed oxides The problem is that aluminum is often added to metal alloys for oxidation protection and the presence of aluminum oxide in the matrix interferes with his capability.

Yes fine Al2O3 powder may be used with only limitation of its density (3.85 gm/cm3 ) against 7.85 for steel in solid state and 7 gm/cm3 in molten state.For high strength at high temperature ODS Yitirium oxide are preferred.

Shivraj Singh Kasana