Torsional creep of polycrystalline NiAl

Polycrystalline NiAl has been deformed in torsion to large strains at temperatures between 800 K and 1300 K. The deformation curves indicate continuous dynamic recrystallization and strain weakening. If applying a conventional power law rheology to the data the activation energy and the stress exponent decrease with increasing stress and/or temperature. A model based on cross-slip of screw dislocations is proposed as the creep mechanism for steady state creep.