Abstract

Investigations of the nanohardness of high purity Cu (111) single crystals containing different amounts of prior plastic strains have been carried out using a Diamond Berkovich indenter. The indenter load was varied in the range 0.625 mN to 125 mN and the indentation sizes thus produced were determined using the unloading curves as well as by directly imaging the residual indentations with an atomic force microscope. The two types of determinations disagreed with each other, with the departure increasing with increasing indenter load. From the AFM measurements, nanohardness versus indenter load plots were made. It was found that although the nanohardness decreased with increasing indenter load, the data were not fitted by any of the existing theories or models. Explanation and discussion of the results and the methods of data analysis will be provided.