Fractographic principles applied to Y-TZP mechanical behavior analysis

Author(s)

Ramos, Carla Mueller ^[1] ; Cesar, Paulo Francisco ^[2] ; Bonfante, Esteuam Augusto ^[3] ; Rubo, Jose Henrique ^[3] ; Wang, Linda ^[1] ; Sanches Borges, Ana Flauia ^[1]

Affiliation

^[1] Univ Sao Paulo, Bauru Sch Dent, Dept Dent Endodont & Dent Mat, Bauru, SP - Brazil

^[2] Univ Sao Paulo, Fac Dent, Dept Biomat & Oral Biol, Sao Paulo, SP - Brazil

^[3] Univ Sao Paulo, Bauru Sch Dent, Dept Prosthet Dent, Bauru, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS; v. 57, p. 215-223, APR 2016.
• Web of Science Citations: 2

Abstract

The purpose of this study was to evaluate the use of fractography principles to determine the fracture toughness of Y-TZP dental ceramic in which K-Ic was measured fractographically using controlled-flaw beam bending techniques and to correlate the flaw distribution with the mechanical properties. The Y-TZP blocks studied were: Zirconia Zirklein (ZZ); Zirconcad (ZCA); IPS e.max ZirCad (ZMAX); and In Ceram YZ (ZYZ). Samples were prepared (16 mm x 4 mm x 2 mm) according to ISO 6872 specifications and subjected to three-point bending at a crosshead speed of 0.5 mm/min. Weibull probability curves (95% confidence bounds) were calculated and a contour plot with the Weibull modulus (m) versus characteristic strength (sigma(0)) was used to examine the differences among groups. The fractured surface of each specimen was inspected in a scanning electron microscope (SEM) for qualitative and quantitative fractographic analysis. The critical defect size (c) and fracture toughness (K-Ic) were estimated. The fractured surfaces of the samples from all groups showed similar fractographic characteristics, except ZCA showed pores and defects. Fracture toughness and the flexural strength values were not different among the groups except for ZCA. The characteristic strength (p<0.05) of ZZ (eta=920.4) was higher than the ZCA (eta=651.1) and similar to the ZMAX (eta=983.6) and ZYZ (eta=1054.8). By means of quantitative and qualitative fractographic analysis, this study showed fracture toughness and strength that could be correlated to the observable microstructural features of the evaluated zirconia polycrystalline ceramics. (C) 2015 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 11/18061-0 - Structural and mechanical analysis and copings of experimental zirconia for use CAD/CAM system
• Grantee: Ana Flávia Sanches Borges
• Support Opportunities: Regular Research Grants