Nanoindentation Creep Behavior of Nanocrystalline Ni and Ni-20 Wt.% Fe Alloy and Underlying Mechanisms Revealed by Apparent Activation Volumes

•Nanoindentation creep behavior and mechanisms of nanocrystalline Ni and Ni- wt.% Fe alloy were investigated.•A loading rate-controlled mode in cooperating with continuous stiffness measurement technique was used.•Continuous creep strain rate versus creep stress data were obtained on each single sample.•Continuous apparent activation volume data were obtained on each single sample.•Nanocrystalline Ni and Ni- wt.% Fe alloy show different creep properties in transient and steady-state regimes.