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

Abstract

The thermoelectric behavior, mechanical properties and microstructures of bulk n-type Si80Ge20 samples prepared by mechanical alloying (grain size <200nm) 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 ∼143GPa for dense sample. Bulk hardness, determined by nanoindentation is 14.5GPa (at 0.1N load). Fracture toughness estimated by Vickers indentation method assuming Palmqvist cracks system is around 1MPa√m.