Fabrication of high-content hybrid-reinforced Al nanocomposites by in-situ reaction of TiO2-decorated CNTs and matrix

Abstract

The idea of intragranular in-situ reactions results in the proliferation of nanoreinforcements in a metal matrix composite. In this regard, high-content multi-component hybrid-reinforced 6061Al composites were synthesized in-situ from template reaction between TiO2-decorated carbon nanotubes (CNTs) and the matrix by flake powder metallurgy. TiO2 nanoparticles were introduced with the help of low-amount of CNT as carrier. The total content of reinforcements increased from 3.4 wt% to ∼17.35 wt% when TiO2-decorated CNTs were completely reacted with the matrix, producing Al4C3/Al4O4C/Al3Ti/Al2O3 compounds during high temperature sintering/extrusion. The as-fabricated hybrid composite exhibited outstanding mechanical properties of high tensile strength (570 MPa) and high Young's modulus (98.6 GPa) at room temperature, which were 105 % and ∼33 % higher than those of 6061Al matrix. Furthermore, the tensile strength of the hybrid-reinforced composite reached 211 MPa at 300 °C, which is about 270 % higher than the matrix. The remarkable mechanical properties were attributed to the in-situ formation of multi-components/nanophases with superior mechanical properties and high thermal stabilities. The results indicate that uniform incorporation of high-content nanophases through the in-situ reaction of nanoparticle-decorated CNTs is a promising path to produce high-performance nanocomposites and can be applied to other composite systems.