Mechanisms and influences of Sc2O3 doping on the structural evolution and properties of Al2O3-ZrO2 fibers

Al 2 O 3 -ZrO 2 biphasic fibers were of considerable interest due to their superior mechanical properties and thermal stability. Despite this, precise control over fiber structure and further enhancement of thermal stability remained significant challenges. This study investigated the regulation of phase transformation behavior and thermal stability in Al 2 O 3 -ZrO 2 fibers through Sc 2 O 3 doping. The findings demonstrated that Sc 2 O 3 doping facilitated the formation of α-Al 2 O 3 and t-ZrO 2 phases within the fibers. In samples containing 1 wt.% Sc 2 O 3 , the average crystal size of α-Al 2 O 3 was 160 nm, while t-ZrO 2 crystals displayed a bimodal nanoscale distribution. The Weibull strength of these fibers reached 1.99 GPa. Following exposure to 1200 °C for 100 h, most α-Al 2 O 3 crystal sizes remained within the 200-300 nm range. The mechanism by which Sc 2 O 3 doping affects structural evolution and enhances the thermal stability of Al 2 O 3 -ZrO 2 fibers was also examined.