Evaluation of fracture toughness of alumina by static and impact three point bending tests.

The static and impact three point bending tests were carried out to evaluate the fracture toughness of alumina. A precrack was introduced into the specimen by BI method. In order to eliminate the influence of residual stress caused by the roughness of the crack surface, a notch was made on the crack with diamond cutter, leaving the crack tip.The static fracture toughness was evaluated by SEPB method. Because of rising R-curve behavior of...