Thermoelectric and mechanical properties of a hot pressed nanostructured n-type Si80Ge20 alloy

The thermoelectric behavior, mechanical properties and microstructures of bulk n-type Si80Ge20 samples prepared by mechanical alloying (grain size <200 nm) and hot pressing are investigated. The measured figure of merit (ZT) is approximately 1 at 800 °C. Young's modulus measured by acoustic echography, four point bending test and nanoindentation is estimated to be ∼143 GPa for dense sample. Bulk hardness, determined by nanoindentation is 14.5 GPa (at 0.1 N load). Fracture toughness estimated by Vickers indentation method assuming Palmqvist cracks system is around 1 MPa√m.