Although there have been numerous computer-simulation studies of the damage
created by displacement cascades in metals, little attention has been paid
to the influence of stress on defect generation in the primary cascade pro
cess. In the present work. molecular dynamics (MD) has been used to investi
gate defect production and clustering by displacement cascades in alpha -ir
on under uniform tensile strain. Cascades of 10 keV primary-recoil energy h
ave been simulated in a single crystal with strain of 0%, 0.1%, 0.5% or 1%
applied along a <1 1 1 > axis, with at least four events modelled for each
condition. The results show that the number of interstitial and vacancy def
ects is smaller in the strained models, particularly for the strain of 0.1%
. This decrease in the number of defects is possibly related to the effect
of strain on self-interstitial motion. leading to enhanced recombination wi
th vacancies. The number of interstitials in clusters is approximately inde
pendent of applied strain, but the fraction of interstitials aligned parall
el to the strain axis increases with increasing strain. The effect is small
at 0.1%, strain, but most single interstitials are created in this orienta
tion at 0.5% and all single and clustered interstitials are aligned at 1%.
These results are discussed in terms of the influence of strain on defect f
ormation energy and the mobility of interstitials. (C) 2001 Elsevier Scienc
e B.V. All rights reserved.