Limits of the Mg–Al γ-phase range by ball-milling

In the present work, the homogeneity range of the Mg–Al γ-phase was studied by ball-milling with post-annealing. In order to estimate the limit of its domain range, several MgXAl100−X compounds from X = 47.5 to 70 by incremental steps of 2.5 were prepared. Different experimental measurements (XRD, SEM, EDX, DSC) were performed and are in mutual agreement with the properties of the existing phases. They show that deviation from the ideal composition of the intermetallic Mg17Al12 structure (X = 58.62) leads to a decrease of the homogeneity (morphological and chemical compositions). Rietveld refinements on XRD patterns show that the single γ-phase range is extended at room temperature and is identified for 55 ≤ X ≤ 62.5 at.% of nominal Mg powder.