Investigation of Ductility and Damage Accumulation by Two Stage Deformation Using Ecae/Ecad and the Tensile Test
Abstract
Lower-Bound Ductility (LBD) is the critical strain at the moment of fracture as a function of stress state and temperature. Measurements of LBD are normally performed by testing in a hyperbaric chamber. There is an alternative approach for determination of the LBD based on the cumulative nature of damage. The basic idea of this new approach is to apply two successive loadings with different stress ratios that lead to fracture, and then to calculate the LBD function.
The processes of equal channel angular extrusion and drawing are used to introduce some damage in the specimen for a specified stress — temperature history. The amount of plastic deformation is determined by the angle between the two intersecting channels, while the stress ratio is varied by applying different back-pressures. The rest of the damage required to cause fracture is introduced by a subsequent tensile test. The LBD diagram for continuously cast Al 6061 has been deduced using this method.
Keywords
Stress Ratio Critical Strain Damage Accumulation Stress Index Equivalent Plastic StrainPreview
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