Bulk mechanical alloying (BMA) followed by hot pressing (HP) was used to prepare Mg2Si0.6Ge0.4 thermoelectric material with high densification. Starting from the elemental power mixture, the Mg 2Si0.6Ge0.4 solid solution was solid-state synthesized via BMA. In fact, the peaks for the cubic-structured Mg 2Si0.6Ge0.4 solid solution phase were detected after 300 cycles in BMA. The single phase of Mg2Si 0.6Ge0.4 was synthesized at 600 cycles in BMA. Mg 2Si0.6Ge0.4 showed p-type semiconduction without doping. Effects of hot pressing conditions on thermoelectric properties were investigated. With increasing hot pressing temperature from 673 to 773 K and pressure from 500 MPa to 1 GPa, the electrical conductivity increased and the Seebeck coefficient decreased. The maximum figure of merit was obtained with the processing parameter of 600 cycles BMA and hot pressing at 773 K, 1 GPa for 1 h.
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