The influence of loading rate on crack bridging processes in Al_2O_3

摘要

Commercially available alumina of 94/100 nominal purity was used to examine the influence of loading rate on toughening mechanisms. For fine-grained alumina, the crack resistance, K_R, was found to be independent of crack length and lading rate. Coarse-grained alumina exhibited strongly rising R-curves where the initial fracture toughness, K_0, was found to the independent of the loading rate. The net toughen- ing, △Kss, in coarse-grained alumina was found to decrease with increasing lading rata. Loading rate effects were independent of testing environment.