Mechanical properties of Ll2 modified titanium trialuminides alloyed with chromium, iron and vanadium

L1(2) modified titanium trialuminides have been prepared by replacing 9 mol% of aluminum in Al3Ti with ternary and quaternary alloying elements of chromium, iron and vanadium. All the materials were recrystallized into single-phase polycrystals with average grain diameters of about 40 mum. Lattice parameters of the 9 at.% chromium- and 9 at.% iron-modified materials were 0.3959 and 0.3939 nm, respectively. Lattice parameters linearly increased with vanadium addition as the fourth element. Compression tests were performed at temperatures ranging from an ambient temperature up to 1300 K. Yield strength was not sensitive to chemical composition among chromium- and iron-modified materials, but it increased with vanadium addition. Strengthening effect of vanadium was retained up to high temperatures. Compressive creep rates at around 1200 K showed the same effect of vanadium. Flow stress fluctuation of about a few percent was observed in an intermediate temperature range. At 500 K, the flow stress began to fluctuate after several percents of plastic deformation, and it continued through the test. At around 600 K, serrations started immediately after yielding and continued to the end. At 800 K, flow stress fluctuations occurred just after yielding. (C) 2002 Elsevier Science B.V. All rights reserved.