Studies on mechanical properties of thermoelectric materials by nanoindentation

In order to fabricate durable and efficient thermoelectric generators (TEG) for applications like automobile waste heat recovery, where thermal stress is a major concern, one needs to assess the mechanical performance of the TE materials. This work reports the hardness and elastic modulus of the moderate temperature range (200-1000 degrees C) TE materials, including half-Heusler, skutterudites, bismuth telluride, silicon germanium alloys, and lead selenide, using nanoindentation and atomic force microscopy (AFM). The p-type half-Heusler exhibits considerably higher hardness and modulus values, and lower brittleness as compared with other materials, which may be indicative of its more robust mechanical performance.