Production of a high strength Al/(TiAl3+Al2O3) composite from an Al-TiO2 system by accumulative roll-bonding and spark plasma sintering

Abstract

A bulk in-situ Al/(TiAl3+Al2O3) composite was fabricated by accumulative roll-bonding (ARB) and spark plasma sintering (SPS) from pure Al sheets and TiO2 nanoparticles. The microstructure and mechanical properties of the composite were investigated. A uniform dispersion of TiO2 nanoparticles in Al matrix was first achieved by ARB processing in the primary Al/TiO2 composites. Subsequent SPS resulted in the formation of hierarchical TiAl3 (∼60 nm) and Al2O3 (∼750 nm) particles that were distributed uniformly in the ultrafine-grained Al matrix. Microhardness and strength (at ambient and high temperatures) of the final composite were substantially enhanced compared with those of pure Al and the primary Al/TiO2 composite, reaching ∼198.6 HV, ∼628.8 MPa at room temperature and ∼384.2 MPa at 300 °C, respectively. The high strength of the Al/(TiAl3+Al2O3) composite was attributed to a superimposition of different strengthening mechanisms.