Effect of ternary iron addition on the creep behaviour of NiAl

Constant load creep tests have been carried out on polycrystalline NiAl in the temperature range 750-900degreesC and at stresses from 35 to 75 MPa. It was found that the creep rate of NiAl is controlled by dislocation climb, which gives rise to a well defined substructure; the addition of iron, which decreases the diffusion coefficient of NiAl, decreases the steady state creep rate of NiAl appreciably. Dislocations with a <100> Burgers vectors operate in both regimes, predominantly on 001 in the primary region and also on {011} in the steady state region. (C) 2002 Elsevier Science B.V. All rights reserved.