AN EVALUATION OF THE FRACTURE RESISTANCE OF ENGINEERING MATERIALS FROM THE FRACTURE SURFACE MORPHOLOGY

— The following work examines the fracture morphology in relation to the COD R-curves of three stainless steels. Additional considerations are noted concerning crack growth behaviour based on simple, optical microscopic observations. Procedures for the determination of R-curves and initiation values are outlined when a multi-specimen technique is used and the crack growth is measured by a light microscope. The COD R-curves are obtained for different conditions which reduce fracture ductility in two 310S and one 304H stainless steels. These conditions include a sigma-phase in one 310S, and sensitization of the large grain size microstructure in the other 310S stainless steel.