It was recalled that computer simulation had shown that a nearby surface could cause a significant increase in the numbers of vacancy defects which were produced by high-energy displacement cascades in metals having a cubic structure. The effect of a surface upon the production of bulk lattice defects in the α-phase, by displacement cascades (up to 10keV), was studied here. Basal and prism planes were considered, with the direction of the primary recoil atom making a high or low angle with respect to the surface normal. This hexagonal close-packed metal was chosen because self-interstitials migrated preferentially along the basal planes and the crystallographic orientation of the surface could therefore affect the final state of cascade damage. The surface and sub-surface damage increased with increasing energy, but the surface damage was much greater for the prism-plane surface. Although stable interstitial defects were more easily generated below a basal-plane surface, they were deposited at greater depths below a prism-plane surface. The production of vacancies and interstitials below the surface was compared with simulated data for cascades in the bulk. The results were explained in terms of the defect properties of Zr.

Defect Production by Near-Surface Displacement Cascades in α-Zr. N.De Diego, D.J.Bacon: Philosophical Magazine A, 2000, 80[6], 1393-406