Dislocations and Grain Size in Electrodeposited Nanocrystalline Ni Determined by the Modified Williamson-Hall and Warren-Averbach Procedures

Electrodeposited nanocrystalline Ni foils were studied by high-resolution X-ray diffractometry. The full width at half-maximum and Fourier coefficients were found to vary rather anisotropically as a function of diffraction order. The modified Williamson-Hall plot and the modified Warren-Averbach analysis, developed recently by taking into account the dislocation contrast in peak broadening, have been applied to interpret this anisotropic behaviour in terms of grain size, dislocation densities and twin boundaries. The average grain size has been found to range between 50 and 12 nm, in good agreement with transmission electron microscopy observations. The average dislocation density has been found to be 4.9 (5) × 10¹⁵ m^-2 and the dislocations are of the screw character.