Microstructure and Mechanical Properties of L1₂-(Al, Cr)₃Ti/Ti₂AlC Composites Prepared by Combustion Synthesis

Abstract

L1₂–(Al, Cr)₃Ti/Ti₂AlC composites have been prepared by the reactive arc-melting technique using elemental powders of Ti, Al, Cr, and C. Resulting composites have been reinforced using 4.5, 9, and 18 vol%Ti₂AlC in a matrix of L1₂ trialuminide Ti–61 mol%Al–13 mol%Cr alloy. The Ti₂AlC particles having a rod-like morphology of 1.5 \\micron width and 5–20 \\micron in length were homogeneously dispersed in the matrix. The matrix grain size was reduced through addition of Ti₂AlC particles. These composite materials have revealed higher mechanical properties (bending strength and fracture toughness) than that of the monolithic alloy. This improvement is attributed to the Ti₂AlC particles dispersion and to the fine grain of the matrix.