crystallization behavior and mechanical properties of in-situ alumina-zirconia composite bodies

Insitu alumina-zirconia composite bodies were fabricated by heat treatment of gibbsite-zircon-kaolinite mixture at 1450℃. the current research investigated crystallization behavior and mechanical properties of the mentioned mixture in the presence of 5 wt.% mgo as an additive. x-ray diffraction (xrd) results showed that alumina, zirconia, and magnesium aluminosilicate were crystallized during the heat treatment at 1250-1550℃. it was expected that mullite and zirconia were crystallized as the final phases; however, the addition of 5 wt.% of mgo changed the behavior of the mentioned mixture during the heat treatment at 1250-1550℃. energy diffractive x-ray spectroscopy (eds) reported that after heat treatment at 1450℃, an al3+-rich aluminosilicate phase was formed as the matrix of the composite. crystallization of alumina and zirconia and the existence of the amorphous aluminosilicate phase formed a composite with appropriate hardness and mechanical strength. the diametral tensile strength and vickers microhardness values of the final composite were 130±7 mpa and 7.49 ± 1.2 gpa, respectively.