Grain structure effects on the lattice thermal conductivity of Ti-based half-Heusler alloys

Half-Heusler alloys with the general formula TiNiSn1-xSbx are currently being investigated for their potential as thermoelectric (TE) materials. A systematic investigation of the effect of Sb doping on the Sn site and Zr doping on the Ti site on the electrical and thermal transport of the TiNiSn system has been performed. Unexpectedly, lattice thermal conductivity kappa(L) appears to increase somewhat randomly with small amounts (x<5%) of Sb doping. Subsequently, an investigation of grain structure in these Sb-doped materials has been found to correlate with the anomalous behavior of kappa(L). Furthermore, effects of submicron grain sizes on kappa(L) in ball milled and shock compressed samples are also presented. (C) 2002 American Institute of Physics.