Materials Development Engineer, Bucyrus-Erie Company, South Milwaukee, Wis.
Pages: 18 Published: Jan 1976
The three mutually-perpendicular fracture plane orientations in a martensitic steel plate were examined both metallographically and fractographically. The nonuniform distribution of inclusions and anisotropy in inclusion shape produced different appearing fractures, yet all were microscopically ductile. Detailed examination of fracture surfaces and fracture surface profiles illustrated the extent of void growth from sulfide inclusions before macroscopic fracture. Comparisons of cementite nucleated void size and prior austenite grain size showed that only a few cementite particles nucleated voids whereas many hundreds existed per prior austenite grain. A mathematical characterization of inclusion distribution illustrated that effective volume fraction of inclusions was dependent on fracture plane orientation and aided in the understanding of anisotropy in fracture strain. This investigation emphasized the compatibility of conventional metallography and stereofractography in analyzing the fracture process.
crack propagation, microstructure, fractography, inclusions
Paper ID: STP29197S