Examination of Toughening Mechanisms of Zirconia Fabricated by Spark Plasma Sintering Methods

Abstract

Ceramics/ metal functionally graded materials (FGMs) have been attracting much attention as composite materials that are intended for application to high-temperature structures. This study fucuses on toughening of ceramics and their matrix composites, which are building blocks of the FGMs. Partially stabilized zirconia (PSZ) with toughening additives such as Ni particles, Inconel fibers, SiC particles, SiC whiskers and a-alumina (Al2O3) particles were fabricated by spark plasma sintering (SPS). Toughening mechanisms were investigated based on their micro and macro-scale mechanical properties and microstructures. Disk bending tests, producing balanced biaxial loading conditions, were conducted probing bending strength at macro scales, while Vickers hardness tests were carried out to estimate fracture toughness and examine toughening mechanisms at micro scales. The results demonstrated that toughness of ZrO2 increased by adding Ni particles, Inconel fibers and Al2O3 particles. Addition of Al2O3 particles highly enhanced disk bending strength and deformability.