Mechanical and heat transport properties of Ti[formula omitted]Zr[formula omitted]NiSn half-Heuslers: A molecular dynamic simulation study using ab initio-based interaction potentials

Abstract

We have developed an interatomic potential tailored to represent in the range of temperatures between 100 K and 1300 K interactions among the different species composing Ti1−xZrxNiSn half-Heusler alloys over the whole range of x. To obtain the potential we considered an embedded atomic model (EAM). The EAM potential was parametrized throughout the fitting to structural formation energies, forces, and stresses produced by ab−initio calculations in selected Ti1−xZrxNiSn structures. With the help of the potential, we study two fundamental aspects of Ti1−xZrxNiSn half-Heuslers by molecular dynamics. The first is related to the heat carried by the lattice vibrations. The second aspect considers the mechanical strength as measured by the Young’s modulus. The simulations agree well with the experimental results for regular ternary half-Heuslers and alloy compositions. For instance, we found that lattice heat conductivity is always larger in ZrNiSn than in TiNiSn, and that ZrNiSn shows the highest Young’s modulus. From the results we can derive strategies for developing new nanostructured materials with improved properties for thermoelectric applications. Quite remarkably, the lattice thermal conductivity is reduced by almost a half in Ti1−xZrxNiSn layered structures. The methodology that we describe here is of great importance since it offers the possibility to improve the design of materials for thermal management devices.