Microcrack statistics on tough (cup-like) fractures

The fractures of several polycrystals with body-centered cubic and face-centered cubic lattices, in particular, of nickel, 18-8 stainless steel and Mo-47% Re alloy were studied with a view of investigating the relationships between the plastic deformations and the impact strength. A scanning electron microscope was used to plot the curves of micropore size distribution in ductile fractures resulting from uniaxial tension at various temperatures (20-600 deg C) and deformation rates (10-2-10-3 1/s). It was shown that the behaviour of the distribution function is explainable in terms of both the concepts of a thermaly activated initiation of cracks and the deformation fracture pattern