Microstructures and material properties of fibrous HAp/Al2O3–ZrO2 composites fabricated by multi-pass extrusion process

Fibrous HAp/Al2O3–ZrO2 composites were fabricated using the multi-pass extrusion process. In the 3rd and 4th passed extrusion bodies, fibrous microstructures were obtained. The 3rd and 4th passed Al2O3–ZrO2 cores used as reinforcement, were about 35 and 4.5 μm in diameter, respectively. In the bodies sintered at over 1400 °C, the HAp decomposed and was transformed to β-TCP and TTCP, in which large numbers of pores were observed. The values of bending strength, Vickers hardness and fracture toughness of the 3rd passed HAp/Al2O3–ZrO2 composites were 178 MPa, 325 Hv, and 3.4 MPa m1/2, respectively while the values of the 4th passed bodies were 190 MPa, 405 Hv and 3.8 MPa m1/2.