Crystal structure and phase stability of the Φ phase in the Al-Mg-Zn system

► The homogeneity range of the Φ phase in the Al-Mg-Zn system at 360 °C and 330 °C has been determined. ► The crystal structure has been solved and refined at two compositions, Al23.2Mg54.6Zn22.2 and Al17.1Mg53.4Zn29.5. ► Total energy calculations show a split up of the homogeneity range at 0 K into Al16Mg50Zn34 and Al10Mg50Zn40. ► A structural variant at Al10Mg50Zn40 is predicted to be only slightly higher in energy at 0 K.