Fracture Behavior of Notched Specimen after Severe Plastic Deformation

Equal channel angular pressing (ECAP) is a deformation process to refine the microstructure of metals and alloys. Although, SPD methods improve strength, but the elongation to failure associated with the movement of dislocations decreased after the first pass. Also, the fracture behavior after SPD should be evaluated. This paper presents for the first time the experimental results on effects of the ECAP process on tensile mechanical properties and ductile fracture strength of 7075 Al alloy. The 7075 Al alloy was subjected to ECAP after solution treatment and significant grain refinement and enhancement in tensile strength and hardness are obtained after ECAP. Then, the ductile static strength of ECAPed 7075 Al alloy weakened by U-notch is investigated under mode loading I. The criterion based on the averaged value of the strain energy density over a control volume at the notch edge in combination with the Equivalent Material Concept (EMC) is applied to assess the static strength of specimens. A sound agreement between experimental data and the results obtained from strain energy density criterion is found.

کلیدواژه ها:

Ductile failure ، U-notch ، Mode I ، Severely Plastic Deformation ، 7075 Al alloy