High-temperature mechanical behavior of B2-ordered Ti–Mo–Al alloys

Abstract Compressive stress–strain responses of stoichiometric and off-stoichiometric B2-ordered Ti–Mo–Al alloys over the temperature range 973–1373 K were examined to investigate the effects of composition and temperature on the mechanical behavior. The Ti–Mo–Al alloys exhibited impressive yield strengths at elevated temperatures, e.g., 818 MPa for Ti50Mo35Al15 at 1073 K and 490 MPa for Ti50Mo25Al25 at 1273 K. Positive temperature dependence of yield strength was observed in Ti50Mo25Al25 below 1273 K but it had not been seen in either Ti60Mo25Al15 or Ti50Mo35Al15 throughout the test temperatures. Dislocation analyses of the compressed specimens indicated that the Ti–Mo–Al alloys primarily deformed via 111 > slip. The mechanisms responsible for the variations of mechanical properties with composition and temperature are discussed by correlating with the antisite defects.