Effect of iron content on mechanical behavior of nanocrystalline nickel and alloys

Highlights: ► We compare mechanical behaviors of nanocrystalline metals by hardness test. ► Corresponding microstructure evolution is estimated by quantitative X-ray analysis. ► The onset of mechanical behavior is dependent on the iron content. ► The increased iron content enhances crystal defects and grain size effects on mechanical behavior. - Abstract: The effect of iron content on mechanical behavior during room-temperature rolling of nanocrystalline Ni, Ni–20 wt% Fe and Ni–30 wt% Fe are investigated by hardness measurement and microstructure characterization. The mechanical behavior of nc metals indicate a combined effect of crystal defects and grain size. Quantitative X-ray diffraction analysis of microstructure evolution shows that the plastic strain corresponding to saturation of defects is in good agreement with the critical plastic strain corresponding to the transition between strain hardening and strain softening. It is found that the onset of mechanical behavior is dependent on the iron content, and the increase of iron content enhances the crystal defects and grain size effects on the mechanical behavior.