Al matrix composites reinforced by high volume fraction of TiAl3 fabricated through combined accumulative roll-bonding processes

Ultrafine-grained Al matrix composites reinforced by TiAl3 particles with volume fractions (Vp) up to ∼49% were fabricated from nano-sized Ti powders and pure Al sheets via room-temperature accumulative roll-bonding (RT-ARB) combined with hot-ARB at high temperatures. The RT-ARB was first applied to disperse the Ti nanopowders uniformly in Al matrix. In situ formation of TiAl3 particles via reaction of Ti and Al was induced during subsequent hot-ARB process at 600 °C. It was found that further hot-ARB at 700 °C can enhance the volume fraction and the dispersion of TiAl3 remarkably. The microhardness and tensile strength of the final composites are significantly improved as compared to those of pure Al and increase with increasing volume fraction of TiAl3, reaching a maximum of ∼180 HV and ∼455 MPa for Vp = 49%, respectively. The high strength of the TiAl3/Al composites can be attributed to the superimposition of strengthening mechanisms which are dominant at high Vp.