Cyclic plasticity of polycrystalline nickel under axial–torsional loading

The axial–torsional cyclic deformation behavior of polycrystalline nickel was investigated by performing fully reversed plastic strain amplitude controlled fatigue experiments at effective plastic strain amplitudes ranging from 1 × 10−4 to 1 × 10−3. Experiments were accomplished under proportional and 90° out-of-phase nonproportional loading paths. Results indicate that loading path has very little effect on the cyclic response at the lower effective plastic strain amplitude. However, at the higher effective plastic strain amplitude, significant additional hardening is induced by the nonproportional loading path.