CREEP IN A NI-15CR ALLOY AT LOW STRESSES AND INTERMEDIATE TEMPERATURES

Creep of a Ni-15Cr solid solution alloy has been studied by means of the helicoid spring specimen technique. The applied stress has varied from 0.2 to 5.0 MPa, the testing temperature from 973 to 1123 K and grain size from 47 to 254 mum. The creep curves exhibit steady state after a normal primary stage. The steady state creep rate can be attributed to the transition from diffusional Coble creep to low temperature Harper-Dorn creep controlled by the pipe diffusion.