Al-(L1<inf>2</inf>)Al<inf>3</inf>Ti nanocomposites prepared by mechanical alloying: Synthesis and mechanical properties

The present paper reports the formation of nanocomposites containing α-Al and L12-Al3Ti in binary Al-Ti alloys containing 5, 10, 15, and 20 at.% Ti. Supersaturated solid solution of Ti in Al was observed after 20 h of mechanical alloying irrespective of the Ti content. Nanocomposites formed after mechanical alloying and subsequent annealing at 673 K for 2 h showed a high hardness (3.4 GPa), modulus (106.4 GPa) and density (95%). Hardness values of Al-(L12)Al3Ti nanocomposites obtained by nanoindentation were similar to hardness measured with microhardness. High strength of the nanocomposites was attributed to the formation of large volume fraction of nanocrystalline L12-Al3Ti particles and the ultrafine grain size of α-Al matrix. © 2009 Elsevier B.V. All rights reserved.