Strain dependent grain growth during cold rolling deformation of gradient nanograined nickel

Abstract

The effect of the rolling strain on grain growth behavior of two gradient nanograined nickel samples (average grain size ranging from 20~90nm) with symmetrical structure was investigated by scanning electron microscope/transmission electron microscopy observation, X-ray line profile analysis and microhardness measurement. In both gradient microstructures, under the same volume fraction, the layer with small grains and the layer with large grains was systematically compared. Quantitative analysis indicated that at a given nominal rolling strain small grains seem to grow more slowly than large grains, which can be attributed to the fact that the “hard” small grains sustain less deformation when the gradient are deformed to a certain strain.