Publication Type
Journal
Journal Name
Journal of Nuclear Materials
Publication Date
Page Numbers
385 to 395
Volume
377
Issue
2
Abstract
Atomic-scale computer simulation has been used to investigate the primary damage created by
displacement cascades in copper over a wide range of temperature (100 K �� T �� 900 K) and
primary knock-on atom energy (5 keV �� EPKA �� 25 keV). A technique was introduced to
improve computational efficiency and at least 20 cascades for each (EPKA,T) pair were simulated
in order to ensure statistical reliability of the results. The total of almost 450 simulated cascades
is the largest yet reported for this metal. The mean number of surviving point defects per
cascade is only 15-20% of the NRT model value. It decreases with increasing T at fixed EPKA
and is proportional to (EPKA)1.1 at fixed T. A high proportion (60-80%) of self-interstitial atoms
(SIAs) form clusters during the cascade process. The proportion is smaller for vacancies and
sensitive to T, falling from 30-60% for T �� 600 K to less than 20% when T = 900 K. The
structure of clusters has been examined in detail. Vacancies cluster predominantly in stackingfault-
tetrahedron-type configurations. SIAs tend to form either glissile dislocation loops with
Burgers vector b = 1/2<110> or sessile faulted Frank loops with b = 1/3<111>. Despite the fact
that cascades at a given EPKA and T exhibit a wide range of defect numbers and clustered
fractions, there appears to be a correlation in the formation of vacancy clusters and SIA clusters
in the same cascade. The size and spatial aspects of this are analysed in detail in part II [26].
The stability of clusters when another cascade overlaps them is also investigated in part II.