SLOW CRACK GROWTH: MACROSCOPIC AND MICROSCOPIC ASPECTS

Modern engineering design against fracture in “safety -critical” structures generally is based on the concept of defect- or damage-tolerance, where projected life is estimated in terms of the time for an assumed initial defect to propagate to some critical size. Accordingly, from a materials standpoint, increased resistance to failure can be achieved by retarding the sub-critical growth of cracks prior to final failure. In the current paper, an overview is presented of several recent advances in the understanding of the salient mechanisms of such slow crack growth, involving fracture under both monotonie and cyclic loading at ambient and elevated temperatures.