Fracture resistance estimation of elastic ceramics in edge flaking: EF baseline

The fracture resistance of single-phase oxide and nonoxide ceramics was studied in flaking the specimen edge with a Rockwell indenter (EF test method) and in bar flexure (SEVNB method). The fracture resistance F(R) and fracture toughness K(Ic) are shown to be proportional, the plot with the F(R)-K(Ic) coordinates is termed the EF base diagram, in which the EF baseline is constructed. It was revealed that the fracture resistance of ceramics was not influenced by chip scar shapes on the specimen edge. The data points for inelastic ceramics with a lower EF barrier to the onset of fracture lay below the EF baseline in the base diagram, while the data points for glasses and ceramics with a higher barrier were located above it. The EF test method is appropriate for comparative evaluation of fracture resistance of ceramics and verification of estimates obtained by other methods. (C) 2009 Elsevier Ltd. All rights reserved.