Deformation conditions for Ni powders undergoing mechanical processing Original Research Article

Ni powders were submitted to mechanical processing by ball milling. The microstructural refinement of the processed powders was followed by X-ray diffraction by evaluating the average crystallite size and the average strain content. The Vickers micro-hardness was also measured. The experimental evidences were rationalized using a phenomenological model, which allowed to estimate the amount of powder processed at individual collisions. The density of dislocations was also estimated and correlated with the experimental Vickers micro-hardness values. The connection between the work- and gain-hardening mechanisms described by the Bailey–Hirsch and Hall–Petch relationships is discussed.