Influence of alumina addition on grain growth and room temperature mechanical properties of 8YSCZ/Al_2O_3 composites

摘要

The effect of the amount of alumina addition on grain growth and room temperature mechanical properties (hardness and fracture toughness) of 8YSCZ/Al_2O_3 composites were determined using 8 mol percent yttria-stabilized cubic zirconia (8YSCZ) and various amounts of Al_2O_3 (0-10 wt percent). The experimental results showed that the grain growth in Al_2O_3 doped SYSCZs occured slowly and more sluggish than that in undoped 8YSCZ. Also, the grain growth rate decreased with increasing Al_2O_3 content. The grain growth exponent value and the activation energy for undoped 8YSCZ were found to be 2 and 289 kj/mol, respectively. The addition of Al_2O_3 raised the grain growth exponent value to 3 and activation energy for the grain growth process was increased from 289 to 410 kJ/mol. Also, the introduction of Al_2O_3 enhanced the hardness and fracture toughness of 8YSCZ/Al_2O_3 composites. The hardness and fracture toughness increased with increasing Al_2O_3 content. The maximum hardness and fracture toughness values reached 1459 kgf/mm~2 and 2.41 Mpam~(1/2), respectively, with the addition of 10 wt percent Al_2O_3 while these values were 1314 kgf/mm~2 and 1.5 MPa m~(1/2) for undoped 8YSCZ.