Chalk River Laboratories

About: Chalk River Laboratories is a based out in . It is known for research contribution in the topics: Neutron diffraction & Neutron scattering. The organization has 2297 authors who have published 2700 publications receiving 73287 citations.

The phonon frequency distribution of vanadium

Abstract: Measurements of neutrons scattered inelastically from vanadium have been made and absolute cross sections determined over a range of energy and momentum transfers of 0-50 meV and 1-12 A-1 respectively. A frequency distribution of the normal modes of vibration in vanadium is evaluated from these data Peaks are observed at energy transfers of 8, 20 5, 25 5 and 28 5 meV (equal to 1 9, 4 9, 6 1 and 6 9 × 10-12 sec-1). Neutron spectra have been calculated using this distribution and good agreement obtained with experimental data. A comparison is made with the frequency distributions of niobium and tantalum.

Neutron diffraction measurements of residual stresses around a crack tip developed under variable‐amplitude fatigue loadings

Abstract: The spatially resolved neutron-diffraction residual stress mappings were performed on five compact-tension (CT) specimens subjected to various variable-amplitude fatigue loadings (e.g. overload, underload and their mixed loads) during fatigue crack propagation. Three principal residual-stress components (i.e. longitudinal, transverse and normal stresses) were measured as a function of the distance from the crack tip along the crack-propagation direction. The shape of respective crack tips on the five CT specimens was examined using scanning electron microscope. The results show the distinct residual-stress fields near the crack tip and significant changes in the crack-tip geometry for five different loading cases. It is thought that the combined effects of the changes in the residual-stress state and crack-tip geometry seem to be a key factor to account for the observed transient crack-growth phenomena.