[T13] Non Ferrous Materials

[15P-T13-08] Superior Combination of Strength and Electrical Conductivity in Cu/Al₂O₃ Composite by Introducing High-volume-fraction Ultrafine Grains

J. Zhang^1,2, X. Liu^2,3, S. Zhang², *W. Huo² (1.Shaanxi University of Science and Technology, China, 2.Northwest Institute for Non-ferrous Metal Research, China, 3.Xi'an University of Technology, China)

Keywords:Cu/Al2O3 composite, ultrafine grains, in-situ Al2O3 nanoparticles, strengthening mechanisms, electrical conductivity

High-strength Cu/Al2O3 composites usually exhibit obviously deteriorated electrical conductivity. A chemical and mechanical alloying-based strategy was adopted to fabricate ultrafine composite powder with low-content reinforcement and construct a combined structure of Cu ultrafine powders covered with in-situ Al2O3 nanoparticles. After consolidation at a relatively lower sintering temperature of 550 ℃, high-volume-fraction ultrafine grains were introduced into the Cu/Al2O3 composite, in-situ Al2O3 nanoparticles with average size of 11.7±7.5 nm were dispersed homogeneously in the Cu grain interior. The composite showed an excellent combination of high tensile strength (654±1 MPa) and high electrical conductivity (84.5±0.1% IACS), which was ascribed to the synergistic strengthening effect of ultrafine grains, dislocations and in-situ Al2O3 nanoparticles. This approach using ultrafine composite powder with low-content reinforcement as a precursor followed by low-temperature and high-pressure sintering may have the potential to be applied to large-scale industrial production of high-performance oxide dispersion strengthened alloys.