ELECTRON MICROSCOPY STUDY OF FIVE-FOLD TWINS IN ELECTRODEPOSITED NANO-TWIN Ni

Abstract

The nanocrystalline Ni thin films with high density nano-scale growth twins were synthesized by direct electrodeposition technology. The five-fold twinning structure in electrodeposited nano-twin Ni was systematically investigated by TEM. The remarkable diffraction pattern and HRTEM images obtained from the cross-section observation demonstrate directly that the electrodeposited nano-twin Ni has five-fold twinning structure with five {111} twinned subcrystals and systematically analyzed the 7.35° intrinsic structural gap. In this work, the 7.35° gap was at least inset in two twin boundaries of the five-fold twin, the twin boundaries which share the 7.35° gap always broaden and was decomposed into other twins, so that, the grain present a irregular shape. cross- sectional TEM micrograph revealed that the electrodeposited nano-twin Ni had columnar grain structure with a strong {110} texture. By means of comprehensive structure characterization, a new space structural model of the five-fold twin was proposed.