Fabrication and Mechanical Properties of Al₂O₃ Solid Solution with Low Addition of Cr₂O₃

Al₂O₃-Cr₂O₃ solid solution with low addition of 0.1 to 1.0 mol% Cr₂O₃ were fabricated by a conventional hot-pressing method, and their mechanical properties such as fracture toughness, strength and deformation behavior at room temperature were investigated as a function of the Cr₂O₃ content using the conventional and nano-indentation methods. The maximum fracture strength of Al₂O₃-Cr₂O₃ solid solutions was observed at 0.4 mol% Cr₂O₃ addition, and the hardness decreased with increasing Cr₂O₃ content up to 0.6 mol%, while the increasing hardness at above this content. Investigation of the indentation impression by means of atomic force microscope showed a completely plastic deformation under indentation load of 300 mN.