Electronic transport properties of alpha-TiAl alloys

Abstract

The electrical resistivity, thermal conductivity, and thermopower of alpha-TiAl alloy samples with A1 content from 0 at.% to 10 at.% are measured from room temperature down to liquid helium temperature. It is found that with the increase in A1 content the single phonon scattering contribution to the resistivity remains nearly constant, but the multiphonon scattering contribution monotonously increases. This provides an alternative explanation of resistivity saturation to the shunt-resistor model. The Wiedemann-Ranz law holds for the whole temperature range, allowing the separation of the electron and phonon contributions to the thermal conductivity. The data from samples with different doping levels enable us to separate the band and the scattering terms in the thermopower.