Creep deformation of Alloys 617 and 276 at 750-950 °C

Alloys 617 and 276 were subjected to time-dependent deformation at elevated temperatures under sustained loading of different magnitudes. The results indicate that Alloy 617 did not exhibit strains exceeding 1 percent (%) in 1000 h at 750, 850 and 950 °C when loaded to 10% of its yield strength (YS) values at these temperatures. However, this alloy was not capable of sustaining higher stresses (0.25YS and 0.35YS) for 1000 h at 850 and 950 °C without excessive deformation. Interestingly, Alloy 617 showed insignificant steady-state creep rate at 750 °C irrespective of the applied stress levels. Alloy 276 almost met the maximum creep deformation criterion when tested at 51 MPa-750 °C. Severe creep deformation of both alloys at 950 °C could be attributed to the dissolution of carbides and intermetallic phases remaining after solution annealing or precipitated during quenching.