Roles of grain boundary microstructure in high-cycle fatigue of electrodeposited nanocrystalline Ni-P alloy

The fatigue properties and the morphology of the specimen surface and fracture surface were investigated in electrodeposited nanocrystalline Ni-P alloy subjected to high-cycle fatigue. The nanocrystalline specimens, which have a {0 0 1} texture and high fractions of low-angle and Sigma 3 boundaries, show a higher fatigue limit than Ni polycrystals with conventional grain size. The change in specimen surface and fracture surface by cyclic deformation is discussed in connection with grain boundary microstructure to reveal the mechanism of fatigue fracture in nanocrystalline materials. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.