Abstract
Crack development has been investigated in sintered iron with porosities between 10 and 20%. The ductility of the samples was changed by O2 or N2 annealing and low temperature deformation. Depending on the work hardening ratio, various characteristic fracture modes have been observed by means of tensile experiments combined with analyses of acoustic emission within the scanning electron microscope (SEM). Corresponding to these fracture modes, the fracture toughness (J c values) showed a strong dependence on porosity and thermal treatment. The behaviour is discussed on the basis of a fracture model for a single sintered neck. PM/0204
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