Creep of .ALPHA.2+.BETA. Titanium Aluminide Alloys.

Abstract

The interest in titanium aluminide alloys includes elevated temperature applications, for which creep resistanc~i s a primary property. Tests have been madebetween 650 and 870'C on a variety of microstructures of Ti-24Al-1 1 Nb and Ti-25Al-10Nb-3M0-1V (ato/o) where i* is the steady-state creep rate at a tensile stress cr, n and A are constants, Q, is the apparent activation energy. R the gas constant, and T the absolute temperature. Therefore, plotting log of steady-state creep rate vs. Iog a will result in a straight line with a slope equal to n, the power-1aw exponent.25~27)The results for the role of microstructure for both Ti-24-11 and Ti-25-10-3-1 can be illustrated with the two examples in Fig. 3 From Ref, 16 Temperature Dependence In addition to the stress exponent n, the apparent activation energy Q, is considered helpful29,35) in establishing the controlling mechanismof creep deformation.In Fig. 5

Tensile properties and high temperature creep behavior of microalloyed Ti–Ti3Al–Nb alloys by directional solidification

“…Unfortunately, quite few investigations have been undertaken up to date on the creep behavior in single ␣ 2 -Ti 3 Al alloys [29][30][31][32]. Furthermore, almost no reports have been available up to date with respect to the high temperature creep deformation in the ternary Ti-Al-Nb alloys with a moderate Al concentration (10-20 at.%), where some of the remaining Ti is employed as the tough phase to enhance the ductility of Ti-Al-Nb alloys resulting in a composite microstructure of Ti-Ti 3 Al-Nb.…”