Core/shell volume effect on the microstructure and mechanical properties of fibrous Al2O3–(m-ZrO2)/t-ZrO2 composite

Al2O3–(monoclinic-ZrO2)/tetragonal-ZrO2 composites (Al2O3–(m-ZrO2)/t-ZrO2) were fabricated by the multi-pass extrusion process to introduce continuously fibrous textures with different core/shell volume fractions of Al2O3–(m-ZrO2) and t-ZrO2 (60/40, 50/50, 40/60, 30/70 and 20/80). The values of the bending strength and fracture toughness increased as the t-ZrO2 shell volume fraction increased, with maximum values of 1031 MPa and 8.1 MPa m1/2 in the 20 (core)/80 (shell) composite, respectively. However, the Vickers hardness value decreased as the core volume fraction decreased due to the increase of t-ZrO2 content.