Solid-state processing of Al-Mg alloys

Abstract

Nanostructured Al-Mg powders with 10 to 90 at.% Mg have been produced by mechanical alloying (MA) of elemental powder mixtures and mechanical milling (MM) of prealloyed ingots. Although the solid-state transformations induced by MA and MM occur by different mechanisms due to the different starting materials used, the present results indicate that MA and MM of Al-Mg powders with the same composition lead to the formation of the same phase(s). Solid solubility extension far beyond the room temperature equilibrium value (∼1 at.% Mg) was achieved by both MA and MM in the range 10 - 40 at.% Mg. The milled powders with compositions between 50 and 70 at.% Mg display the formation of single-phase γ-Al12Mg17, revealing that solid-state processing suppresses the formation of β-Al3Mg2 and hcp Mg in this composition range. No formation of β-Al3Mg 2 was observed during milling for the entire composition range studied. Finally, in the range 80 - 90 at.% Mg, MA as well as MM lead to the formation of two-phase nanostructured powders containing γ-Al 12Mg17 and hcp Mg. © 2009 IOP Publishing Ltd.