MECHANICAL PROPERTIES OF THREE DIFFERENT ALUMINA-ZIRCONIA COMPOSITES

HEIDY L. CALAMBÁS PULGARIN; ALBANO, M. P

Congreso; 59 Congresso Brasileiro de Cerámica; 2015

Asociación Brasileira de Cerámica

ABSTRACTTwo 3 mol% yttria-partially stabilized ZrO2 powders, 0.3 wt% Al2O3-doped and without Al2O3, and a Zr (IV) precursor were used to produce alumina-zirconia composites. The influence of both the zirconia content and the reduction of zirconia particle size on the microstructure development and mechanical properties were investigated. The increase in the zirconia content from 10.5 to 22 vol% increased the hardness; above 22 vol%ZrO2 the hardness decreased. A significant increase in the fracture toughness with increasing the ZrO2 content over 22 vol% was obtained by the stress-induced phase transformation. The flaw size limited the strength below 22 vol%; above 22 vol% ZrO2 the strength was controlled by the stress-activated phase transformation. For 10.5 vol% ZrO2, the smaller ZrO2 grains produced by using the Zr (IV) precursor resulted in higher hardness;however, the tetragonal-monoclinic transformation of some unstabilized ZrO2 grains during cooling reduced the young΄s modulus and fracture toughness.