Fracture Toughness (KIC) of a Dental Porcelain Determined by Fractographic Analysis

Published

September 1, 1999

Author(s)

Susanne Scherrer, J R. Kelly, George D. Quinn, K Xu

Abstract

Fractographic analysis of indentation cracks is performed following flexure testing as part of the ASTM (1997) standard for fracture toughness, K_Ic, determination in advanced ceramics. The purpose of this study was to evaluate the use of fractography in fracture toughness methods with a feldspathic dental porcelain, in which K_Ic was measured fractographically as well as numerically using two controlled-flaw beam bending techniques. No significant differences were found between numeric and fractographic K_Ic values for the IS technique at both indentation loads (9.8N and 19.6N) in ambient air, although K_Ic values were sensitive to indentation load. Stable crack extension was observed fractographically in all IS specimens, as differences between initial (ainitial) and critical (acritical) crack dimensions. For the SCF method, there was a significant difference in toughness between specimens tested in air versus dry nitrogen, however no fractographic evidence for chemically-assisted slow crack growth (SCG) was observed.

Citation

Dental Materials Congress

Volume

15

Issue

No. 5

Pub Type

Journals

Keywords

ceramics, dental ceramics, fractography, fracture toughness, indentation

Citation

Scherrer, S. , Kelly, J. , Quinn, G. and Xu, K. (1999), Fracture Toughness (K_IC) of a Dental Porcelain Determined by Fractographic Analysis, Dental Materials Congress (Accessed April 25, 2024)