A predictive analytical model of thermal conductivity for aluminum/transition metal high-entropy alloys

A predictive analytical model for the thermal conductivity of Aluminum/transition metal based high-entropy alloys based on contributions from the electron and lattice subsystems is presented. Lattice conductivity is modeled as an oscillator damped by electron-phonon and defect scattering. Electron subsystem conductivity is dominated by scattering from the aperiodic crystal potential arising from alloying atom induced lattice disorder; its effect was quantitatively calculated using a virtual crystal approximation. We show that model predictions agree with published values and for an exemplar high-entropy alloy largely based on transition (i.e., non-refractory) elements, AlxCoCrCuyFeNi. Within this alloy system, the crystal structure varies between face centered cubic and body centered cubic depending on composition and temperature, and it was found that thermal conductivity behaves as a weighted-average composite of the multiple phases.