Investigation of the mechanical properties of Al₂O₃ ceramics produced with Sm₂O₃ additive in different ratios

Advanced ceramics are very important in armor applications with their high mechanical properties and lightness. Although Al2O3 offers affordable cost and wide usage potential, it cannot show the desired performance under multiple impact conditions due to its low toughness and bending strength. In this study, it was aimed to examine the condensation properties and increase the mechanical properties of Al2O3 ceramics by adding Sm2O3, a rare earth oxide, to evaluate them in armor applications. Sm2O3 and Al2O3 powders were mixed by ball milling, and Al2O3-Sm2O3 ceramics were prepared by dry and cold isostatic pressing in disk form before sintering without pressure separately at 1550°C and 1600°C/2 hours in air. Sm2O3 reacted with Al2O3 to form SmAlO3. The rod-like morphology of SmAlO3 was more evident in the samples sintered at 1550°C. In ceramics containing 0.5% Sm2O3 by volume sintered at 1600°C, a strength increase of approximately 5% was achieved due to higher densification compared to Al2O3, while the strength values were generally close to each other. The toughness of rod samples prepared in rectangular prism form of Al2O3-Sm2O3 ceramics was measured. The highest toughness values were obtained for the composite containing 0.8 vol% Sm2O3. It has been observed that the addition of existing amounts of Sm2O3 causes an approximately 70% increase in the fracture toughness of the mechanical properties of Al2O3 ceramics, while it does not cause a significant increase in other mechanical properties but changes the microstructure.