Thermal-cycling creep of g-TiAl-based alloys

In two-phase TiAl-based alloys, the coexisting 2 and phases exhibit a thermal expansion mismatch, so that increased creep rates during thermal cycling may be expected. Creep deformation of two g-TiAl-based alloys was investigated during thermal cycles between 900 and 300 or 350 C with applied tensile stresses of 32.5 or 37.0 MPa. Measured thermal cycling creep rates were compared with isothermal creep rates calculated at the e€ective average temperature. No creep enhancement was measured upon thermal cycling within uncertainties of 1.6 10ÿ3% strain per cycle. # 2000 Elsevier Science Ltd. All rights reserved.