Effect of electron concentration on electrical conductivity in in situ Al-TiB2 nanocomposites

Electrical conductivity is important for the applications of metals containing nanoparticles, and a thorough understanding of how nanoparticles affect their electrical conductivity is much needed. In this paper, an in situ Al-TiB2 nanocomposite is used as a model system to study its electrical behavior from 10-300K with Hall scanning up to +/- 6 T. By experimentally identifying the respective contributions from the nanoparticle size, grain boundaries, dislocation density, and nanoparticle volume percentage, it suggests that a low volume percent of TiB2 nanoparticles can reduce the electron concentration significantly to decrease the electrical conductivity of the Al-TiB2 nanocomposites, while yielding less effect on the electron mobility. Moreover, the results show that the intrinsically enhanced electron-phonon interaction and the interfacial bound states by TiB2 nanoparticles play a role in lowering the electron concentration. This understanding of how nanoparticles affect the electrical conductivity provides useful insights into the rational design and optimization of metal matrix nanocomposites for numerous applications.