Cyclic Fatigue Crack Propagation in Alumina under Direct Tension—Compression Loading

Abstract

Cyclically induced crack propagation occurs in alumina subjected to direct tension—compression loading. The crack increment per cycle (da/dN) has a power‐law dependence on the peak stress intensity factor (Kmax). Cyclic crack growth can occur at lower values of Kmax than are required to produce static fatigue effects. Subcritical crack‐growth behavior was found to be dependent on specimen geometry: it is suggested that direct compressive loads and crack length are both factors that affect cyclic fatigue behavior, and that the use of K alone to characterize fatigue crack growth in ceramics may be questionable.