Determination of Dislocation Densities in Hexagonal Close-Packed Metals using X-Ray Diffraction and Transmission Electron Microscopy

Abstract

X-ray diffraction (XRD) line-broadening analysis has been used to determine dislocation densities in zirconium alloys with hexagonal closepacked (hep) crystal structures and a complex distribution of dislocations reflecting the plastic, anisotropy of the material. The validity of the technique has been assessed by comparison with direct measurements of dislocation densities in deformed polycrystalline and neutron-irradiated single crystal material using transmission electron microscopy (TEM). The results show that-there is good agreement between the XRD and TEM for measurements on the deformed material whereas there is a large discrepancy for measurements on the irradiated single crystal; the XRD measurements significantly underestimating the TEM observations.

Effect of Xe26+ ion irradiation on the microstructural evolution and mechanical properties of Zr–1Nb at room and high temperature

“…The dislocation density q can be estimated based on the results of domain size and microstrain from the relation [25] q / e 2 lnð0:05D v Þ ð7Þ…”

Evolution of Face-Centered Cubic Ti Alloys Transformation by X-ray Diffraction Profile Analysis in Mechanical Alloying

“…To estimate the value of ρ s , Equation (2) factor F takes a value of 1 when n is equal to 1 in Equation (1), ε is the microstrain, b is Burger's vector, and k is a constant with values between 2 and 25. Nevertheless, according to Griffiths et al [61], Equation (2) only applies in cubic crystal structures because it ignores the anisotropic nature of the hcp crystal structure [62,63]. For this reason, Griffiths et al adapted Williamson and Smallman's hcp crystal structure, proposing Equation (3).…”

Deformation of zirconium irradiated by 4.4 MeV protons at 347 K

“…The texture was measured and the dislocation density estimated using X-ray diffraction [21,22]. The inverse pole figure in the normal direction of the foil indicated that the resolved fraction of basal plane normals in the foil normal direction was, typically, 0.74.…”