Fracture of Al-4% Cu-0.1% Fe single crystals

The fracture behaviour of heat-treated Al-4% Cu-0.1% Fe single crystals was studied in tension at room temperature. Three heat-treatment conditions were examined: quenced, fully hardened and overaged. Slip lines, shear bands and fracture surfaces were studied to yield information on the plastic deformation processes occurring prior to fracture. The presence of stable Al₇Cu₂Fe particles was found to be an important factor in fracture formation. In the as-quenced condition two fracture planes of different topography were formed. Large shear zones together with scattered shallow dimples were observed in both planes due to stable particles. In the fully hardened condition fracture occurred without necking and usually by shearing along the conjugate slip system. The presence of shear zones and dimples of different sizes was observed. Finally, in the overaged condition fracture took place by void coalescence after strong necking, as in polycrystalline samples. No shear zones were observed on the fracture surface of these samples.