Nanomechanical layer characterization of graded ATZ and ZTA composites

Abstract

Y-TZP presents the highest mechanical properties among all-ceramic systems available, however it is susceptible to low temperature degradation, which may compromise physical and mechanical properties of prostheses. This problematic was the motivation behind the Young Investigator Grant FAPESP #2012/19078-7 and has allowed the development of aging-resistant alumina-zirconia composites (ZTA and ATZ). Bioinspired glass infiltration in Y-TZP systems has demonstrated improved optical and mechanical properties, as well as adhesive bond strength. In this post-doctoral scholarship FAPESP #2019/08693-1, we proposed the glass infiltration of the developed ZTA and ATZ composites to boost their physical and mechanical properties, where a graded layer of 100 um and an increase of 250 MPa in flexural strength relative to non-infiltrated composites was observed. For comprehensive characterization of the graded materials, this BEPE proposal aims to further evaluate the mechanical properties of the layers and throughout their transitions of graded ZTA and ATZ composites using nanoscale indentation and finite element analysis (FEA). Experimental ZTA and ATZ disc-shaped specimens will be processed and infiltrated with silicate glasses. After sintering, the specimens will be sectioned and polished. Half of them will be subjected to hydrothermal aging. Nanoindentation will be performed by means of a Berkovich diamond pyramid probe at several regions of interest at intervals of 25 um to determine the gradient of hardness, elastic modulus, and residual stress of the glass, graded, and composite layers. The collected properties will be used to design a disc (ISO 6872:2015) for in silico non-linear dynamic FEA to be correlated with biaxial flexural strength data. (AU)