Effect of the Addition of ZrO2 Having Different Crystal Structures on the Mechanical Properties of Al2O3
Alumina has been widely used as a structural ceramic because of high hardness and chemical stability. However, due to the unique characteristics of low fracture toughness of ceramic materials, it has seen limited use as a dynamic structural material. Recently, zirconia toughened alumina (ZTA) has been receiving spotlight, which has various toughness mechanisms caused by the volume change associated in the phase transformation process of ZrO2 particles dispersed in Al2O3 to increase the toughness of Al2O3. In this study, 8 mol% Y-ZrO2 and 12 mol% Y-ZrO2 with different crystal structures was dispersed in Al2O3 individually as a stabilizer and the mechanical properties of the ZTA were observed by differing the composition of the stabilizer. Experimental results show that the ZTA specimens with 12 mol% Y-ZrO2 which contains a large amount of stable cubic crystal phases had relatively higher micro hardness values. Whereas, fracture toughness of ZTA specimens with 8 mol% Y-ZrO2 which contains many unstable tetragonal crystal phases, was measured to have higher values than ZTA specimens with 12 mol% Y-ZrO2, which was opposite to that of micro hardness.
Junichi Hojo, Tohru Sekino, Jian Feng Yang, Hyung Sun Kim and Wen Bin Cao
H. Y. Lim et al., "Effect of the Addition of ZrO2 Having Different Crystal Structures on the Mechanical Properties of Al2O3", Materials Science Forum, Vol. 922, pp. 68-73, 2018