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 (α-Mg and LPSO) alloys, the flow stresses of α-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 α-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.

► Flow stresses of new Mg–Zn–Y alloys with a long period stacking ordered (LPSO) structure are measured.
► Mixture rule of flow stress of the Mg–Zn–Y alloys is discussed.
► Mixture rule of flow stress of the Mg–Zn–Y alloys is applied to finite element analysis for forging.
► The proposed method provides high accuracy calculation results.
► Deformation behaviour of the Mg–Zn–Y alloys is discussed from the results of the finite element analysis.