Evaluation of Bridging Parameters in Aluminas from <i>R</i> ‐Curves by Use of the Fracture Mechanical Weight Function

Abstract

Coarse‐grained Al 2 O 3 shows an R ‐curve behavior which is characterized by an increase in crack growth resistance with increasing crack extension. In case of alumina, this effect is caused by crack‐border interactions in the wake of the advancing crack. In the first part of the paper, the weight function method for the determination of bridging stresses from controlled fracture tests is described. In the second part, this procedure is applied for the evaluation of our own experimental results as well as results available in the literature.