Abstract
Fracture toughness(K1c) of polycrystalline silicon carbide was evaluated using a single edge precracked beam(SEPB) method. A Knoop indentation microcrack was introduced into a specimen, and then a sharp pop-in precrack was developed by applying the bridge indentation technique. The precrack length was varied by changing the indentation load and/or the support groove width. The precracked specimens were fractured by three-point bending under a cross-head speed of 0.5mm/min at room temperature. K1c values for silicon carbide decreased with the increase of the indentation load. The indentation load dependence on the K1c values was discussed from the consideration of the residual stress around the indentation crack.
