Dislocation loops in neutron-irradiated copper
Electron transmission microscope observations were carried out on copper irradiated with neutrons at temperatures of 35 deg C and 60 to 100 deg C, and subsequently thinned by electropolishing. Specimens irradiated to a dose of 6.7 x 10/sup 17/ cm/sup -2/ (at 35 deg C) contain approximately 3 x 10/sup 15/ defects c.c./sup -1 / in the form of small regions of strain (average diameter approximately 75 A), some of which can be resolved as dislocation loops. With increasing dose of irradiation (5.6 x 10/sup 18/, 1.4 x 10/sup 20/ n cm/sup -2 many more of the defects can be recognized as loops, and their average diameter increases to approximately 150 and approximately 300A, respectively. The dislocation density in the form of loops is 10/sup 10/ to 10/sup 11/ cm/sup -2/. The stability of the loops and their behavior on annealing are as expected from prismatic loops. The loops are considered to nucleate as a result of the collapse of discs of vacancies produced by vacancy clustering in the central region of a displacement spike, and to grow by migration of vacancies or of vacancy clusters. Radiation hardening is interpreted in terms of the large density of dislocations in the form of loops. The hardening anneals out at the same temperature at which the loops are observed to disappear by climb.
- Research Organization:
- Cavendish Lab., Cambridge, Eng.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-14-009828
- OSTI ID:
- 4186823
- Journal Information:
- Philosophical Magazine, Journal Name: Philosophical Magazine Journal Issue: 48 Vol. 4; ISSN 0031-8086
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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