Constitution of magnesium–indium alloys containing 23–100 atomic % indium

Abstract

A constitutional diagram for magnesium–indium alloys containing between 23.2 and 100 atomic % indium has been established using differential thermal analysis, electrical resistivity, and metallographic methods.An intermediate solid solution, β, with a wide range of homogeneity, is formed peritectically from the liquid and α, the magnesium primary solid solution. It extends between 23 atomic % indium at 485.3 °C and 86 atomic % indium at 160.2 °C, where it is in equilibrium with γ, the indium primary solid solution. Magnesium has a limited solid solubility in indium of about 6 atomic %.For alloys containing up to 50 atomic % indium, the derived constitutional diagram is in good agreement with that of a previous investigation (2). Two exceptions are noted: first, there is no evidence of a long period superlattice, β′′′ of the CuAu II type, and second, a reaction is observed involving a transition between the two ordered phases β′ and β′′. For the indium-rich alloys no intermediate or ordered phase formation is observed.The results have been discussed in terms of the existing phase diagrams.