Unusual thermal performance in Cu-60Ag by WC nanoparticles

Abstract

Nanoparticles have been widely used to tune the mechanical, thermophysical, and chemical properties of materials for widespread applications 1-3. Despite achieving other unprecedented functionalities, metals containing ceramic nanoparticles often suffer a significant loss in thermal conductivity with theoretical upper limits set by the Hashin-Shtrikman (with interfacial interactions) and Weiner (without interfacial interactions) models. Here, we discover that the Cu-60Ag alloy with 10 vol% WC nanoparticles delivers a surprisingly high thermal conductivity, breaking the theoretical upper limits. To understand the underlying mechanisms, thermal transport contributions from phonons and electrons, as well as microstructure, are studied. The study suggests that there exists an unusual enhancement of thermal transport in Cu-60Ag by the less conductive WC nanoparticles. Though thermal analysis including 3ω-method may be needed to decouple influencing factors, this new finding is of significance for development and application of nanoparticles reinforced metals with both superior mechanical strength and high thermal conductivity.