Influence of hot deformation and composition on microstructure development of magnesium-stannide alloys

The microstructural evolution of different compositions of Mg-Sn alloys (30%Sn-70%Mg, 40%Sn-60%Mg and 50%Sn-50%Mg) is studied at first to understand the changes observed with change in tin content and deformation conditions. The Mg2Sn phase increases with increase in tin content and a significant substructure development is found in 50%Sn-50%Mg alloy. The above observation led to further deformation studies on Mg2Sn based thermoelectric materials with higher tin percentage. The microstructure in terms of Electron backscatter diffraction (EBSD) measurements is studied in detail followed by the determination of thermoelectric properties i.e., Seebeck coefficient and electrical conductivity for both as cast and extruded Mg(2+x)Sn-Ag alloys. The electrical conductivity of the extruded Mg(2+x)Sn-.3wt%Ag {x = 1} alloy was found to be more than its as cast counterpart while the Seebeck coefficient values remained almost the same.