Nanoindentation study of nanocrystalline nickel

Abstract

The mechanical properties of nanocrystalline (Nc) Ni (electrodeposited, sintered, rolled) and microcrystalline (Mc) Ni were investigated by nanoindentation technique. Force-displacement curves generated during loading and unloading of the nanoindenter tip (Berkovich diamond tip) were used to determine the hardness and elastic properties of the Nc-nickel. The influence of loading rate on the hardness of electrodeposited Nc-Ni and microcrystalline (Mc) Ni were studied in the present work. The electrodeposited Nc-nickel exhibits higher hardness and elastic modulus when compared to sintered Nc-nickel. The higher modulus of elasticity is observed for the rolled Nc-nickel due to the increased defect density and less porosity in the samples. The higher modulus of elasticity is observed for Mc-nickel when compared to that of Nc-nickel (electrodeposited) with varying load rate. The strain rate sensitivity of Nc-nickel is due to the grain boundary affected zone. © World Scientific Publishing Company.