In-situ X-ray diffraction of mechanically milled beta-Al3Mg2 powders
Résumé
The structure evolution during heating of mechanically milled single-phase beta-Al3Mg2 has been investigated by in-situ X-ray diffraction The nanoscale supersaturated Al(Mg) solid solution formed during milling transforms back, to the original beta-Al3Mg2 phase through a sequence of phase transformations, At low temperatures, an increasing 11 a I mount of Mg rejected from the solid solution with increasing temperature. At intermediate temperatures, the beta'-phase, a hexagonal phase with composition Al3Mg2, forms. Finally, I at higher temperatures them original beta-Al3Mg2 phase is restored, indicating that the formation, of the supersaturated solid solution during milling can be reversed. by appropriate heat treatment. The phase transformations during heating are gradual and the temperature ranges of stability of the different structure configurations are quite large, all exceeding 50 K.