Correlation of the indentation fracture resistance measured using high-resolution optics and the fracture toughness obtained by the single edge-notched beam (SEPB) method for typical structural ceramics with various microstructures

Abstract

The standardized SEPB method and an accurate IF technique recently developed by the authors were employed in order to clarify the correlation of KIC and KIFR for ceramics with various microstructures. Both KIFR calculated using Miyoshi׳s equation and Niihara’s equation were roughly proportional to KIC but the correlation was incomplete. KIFR calculated using Miyoshi׳s equation has a tendency to exhibit slightly smaller values than their KIC. In contrast, the relation between KIFR and KIC was reversed when Niihara׳s equation was used for the calculation of KIFR.