Steady-state creep behaviour of Ti₃Al-base intermetallics

Abstract

The steady-state creep behaviour of Ti₃Al and Ti₃Al+10 wt% Nb was studied in the temperature range 550 to 825° C and in the stress range 69 to 312 MN m⁻². The temperature and stress dependences of the steady-state creep rates were determined for both intermetallics, and the activation energy and stress-exponent were measured. At temperatures above 700° C, the stress dependence of the steady-state creep rate indicated two distinct creep regimes: at stresses above 138 MN m⁻², the creep was controlled most probably by dislocation climb; at stresses below 138 MN m⁻², a transition regime with a lower stress-exponent value was obtained.