Thermal-cycling creep of gamma-TiAl-based alloys

In two-phase TiAl-based alloys, the coexisting alpha(2) and gamma phases ex hibit a thermal expansion mismatch, so that increased creep rates during th ermal cycling may be expected. Creep deformation of two gamma-TiAl-based al loys was investigated during thermal cycles between 900 and 300 or 350 degr ees C with applied tensile stresses of 32.5 or 37.0 MPa. Measured thermal c ycling creep rates were compared with isothermal creep rates calculated at the effective average temperature. No creep enhancement was measured upon t hermal cycling within uncertainties of 1.6x10(-3)% strain per cycle. (C) 20 00 Elsevier Science Ltd. All rights reserved.