The initiation of ductile fracture in pure metals

Microscopic examinations have been made of the necked regions of pure aluminium and copper in single crystal and polycrystalline form. The present experiments suggest that cracks initiate on the coarse slip bands which are characteristic of the deformation in the necked regions. As these cracks do not nucleate at inclusions, it is considered that a dislocation mechanism can contribute to ductile...