Effect of plastic deformation on microstructure and thermoelectric properties of Mg2Sn alloys

Abstract

In the present work, the effect of deformation on microstructure and thermoelectric properties of Mg2Sn alloys having excess magnesium concentrations is examined. The cast alloys were prepared using radio-frequency (RF) induction melting under an argon atmosphere. These alloys were thermo‐mechanically processed via compression at different temperatures to various true strains. At room temperature, the alloys failed at a true strain of ∼13%. However, at elevated temperatures, the alloys were observed to be highly plastic. For alloys compressed at 673 K to a true strain of 1, a prominent substructure formed. The subgrain size was ∼3–5 µm. It is believed that the substructure arose from the action of dynamic recovery. Following deformation, the thermoelectric performance of alloy prepared with 6.7 wt.% excess Mg was improved compared to the as cast condition. This can be ascribed to a reduction in the thermal conductivity due to phonon scattering at grain boundaries.

Keywords

• Magnesium
• Thermoelectric
• Deformation
• Grain size