Characterization of the Elastoplastic Response of Low Zn-Cu-Ti Alloy Sheets Using the CPB-06 Criterion

Abstract

Unlike other HCP metals such as titanium and magnesium, the behavior of zinc alloys hasonly been modeled in the literature. For the low Zn-Cu-Ti alloy sheet studied in this work, theanisotropy is clearly seen on the stress-strain curves and Lankford coefficients. These featuresimpose a rigorous characterization and an adequate selection of the constitutive model to obtain anaccurate representation of the material behavior in metal forming simulations. To describe theelastoplastic behavior of the alloy, this paper focuses on the material characterization through theapplication of the advanced Cazacu-Plunket-Barlat 2006 (CPB-06 for short) yield function combinedwith the well-known Hollomon hardening law. To this end, a two-stage methodology is proposed.Firstly, the material characterization is performed via tensile test measurements on sheet samplescut along the rolling, diagonal and transverse directions in order to fit the parameters involved inthe associate CPB-06/Hollomon constitutive model. Secondly, these material parameters areassessed and validated in the simulation of the bulge test using different dies. The results obtainedwith the CPB-06/Hollomon model show a good agreement with the experimental data reported inthe literature. Therefore, it is concluded that this model represents a consistent approach to estimatethe behavior of Zn-Cu-Ti sheets under different forming conditions.