Formation of Mg5Al8 phase in Al-Mg non-saturated solid solution during electron irradiation

Data on formation of Mg5Al8 phase in Al-0.1% Mg and Al-0.44% Mg nonsaturated solid solutions during electron irradiation in high-voltage microscope are presented. Formation of this phase in Al-Mg nonsaturated solid solutions is found for the first time. Foils have been irradiated in the JEM-1000 high-voltage microscope by electrons with energy of 1 MeV at room temperature. Irradiation intensity constituted approximately 2x1018 and approximately 6x1018 cmxs-1. It is shown that during electron irradiation of A1-Mg nonsaturated solid solutions both typical radiation defects at some distance from flow-loops and Mg atoms segregations and the phase identified as Mg5Al8 phase are found for the first time. Mg5Al8 phase precipitation during irradiation does not agree with equilibrium state diagram of studied Al-Mg alloys and is a result of concentration heterogeneity introduced by irradiation