Cyclic stress–strain behavior of conventional grain and ultrafine grain nickel under biaxial straining

Results are presented on the effects of biaxial straining on the cyclic stress–strain response of ultrafine grain nickel (grain size ≈ 260 nm) and conventional grain nickel (grain size ≈ 50 μm) over a range of effective plastic strain amplitudes from 1 × 10−4 to 1 × 10−3. Grain refinement causes an increase in saturation stress. For conventional grain nickel, non-proportional straining causes higher saturation stress than proportional straining; but the ultrafine grain material exhibits the opposite behavior.