Application of mixture rule to finite element analysis for forging of cast Mg-Zn-Y alloys with long period stacking ordered structure

To establish forging process for high strength Mg-Zn-Y alloys with a long period stacking ordered (LPSO) structure, the flow stresses of Mg-Zn-Y alloys with different volume fractions of LPSO phase were measured by the upsettability test. Since mixture rule for the flow stress was satisfied in Mg-Zn-Y two-phase (alpha-Mg and LPSO) alloys, the flow stresses of alpha-Mg and LPSO single phase alloys were estimated from the flow stresses of Mg-Zn-Y alloys with different volume fractions of LPSO phase. To examine the validity of the mixture rule, the finite element analysis for tensile test and forging of as-cast Mg-Zn-Y alloy was carried out using the estimated flow stresses of alpha-Mg and LPSO single phase alloys on the basis of mixture rule of the properties of Mg-Zn-Y alloy. The calculated load-stroke curves in tensile test and forging agreed well with the experimental ones, and the deformation behaviour of Mg-Zn-Y alloy was discussed. (C) 2012 Elsevier B.V. All rights reserved.