Predicting flow localization and formability of aluminium alloy sheets

In the present investigation, limit strains are calculated on the basis of the yield criterion proposed by Hosford for sheets having planar isotropy in conjunction with the Voce, the Tian-Zhang and the power-law material constitutive equations. The model is capable of predicting the limit strains achievable during a uniaxial tension test and also the left-hand side of forming limit curves. Therefore it can be only applied to deformation mode in which one in-plane strain is compressive and the other is tensile. Results from this analysis are compared with the experimental data for AA3105 and AA8011 aluminium alloys. The results indicate good predictions of limit strains for the two alloys when stress-strain data from tensile tests are fitted to the Voce and the Tian-Zhang equations.