Phase assemblage effects on the fracture and fatigue characteristics of magnesia-partially stabilized zirconia

Abstract

A detailed investigation on the relationships between phase assemblage and fracture and fatigue characteristics of Mg-PSZ has been conducted. In doing so, three completely different microstructural conditions were first attained through different thermal treatments and then their flexural strength, fracture toughness, and crack growth resistance and fatigue crack growth (FCG) behaviour were evaluated. The obtained results are discussed considering the interplay between microstructural features and dominant crack-microstructure interaction and its influence on the operation of given toughening and mechanical fatigue mechanisms for each phase assemblage studied. FCG resistance, under both sustained and cyclic loading, is found to be closely related to the corresponding fracture toughness of each phase assemblage. However, real mechanical fatigue effects are estimated to be, once they are rationalized with respect to particular environmental-assisted cracking behaviours, an exclusive function of crack path type. Finally, different cyclic fatigue mechanisms for Mg-PSZ are pinpointed depending upon the prevalent transgranular or intergranular FCG morphology. © 1998 Elsevier Science Ltd. All rights reserved.