Grain size and alloying effects on dynamic recovery in nanocrystalline metals

Dynamic recovery in nanocrystalline Ni and Ni50Fe50 with respective grain sizes of 65 rim and 15 nm is studied using stress reduction tests during in situ X-ray diffraction. The results are compared with a previous study on NC Ni with 35 nm grain size. Defect recovery by means of grain boundary processes plays an important role in controlling the strength evolution resulting in a constant flow stress during uniaxial deformation. The relative contributions of dislocation and grain boundary accommodation mechanisms are discussed in terms of grain size and alloying. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.