|Author||Smallman, R. E. ♦ Westmacott, K. H.|
|Source||United States Department of Energy Office of Scientific and Technical Information|
|Subject Keyword||RADIATION EFFECTS ON MATERIALS ♦ ABSORPTION ♦ ALPHA PARTICLES ♦ ALUMINUM ♦ ANNEALING ♦ CAVITIES ♦ COPPER ♦ DEFECTS ♦ DISLOCATIONS ♦ ELECTRON MICROSCOPY ♦ FILMS ♦ GOLD ♦ HEAT TREATMENTS ♦ MECHANICAL PROPERTIES ♦ METALS ♦ NEUTRONS ♦ QUENCHING ♦ RADIATION EFFECTS ♦ SCATTERING ♦ SILVER ♦ VACANCIES ♦ X RADIATION|
|Abstract||The effect of introducing point defects into pure metals by (a) quenching and (b) irradiation was studied using the small-angle x-ray scatter technique. Scattering was obtained from both quenched copper and aluminum after appropriate ageing treatments, from alpha -irradiated copper after annealing, and from neutron-irradiated copper. The source of scattering was considered in each case. Direct observation of the scattering defects was obtained for the quenched, neutron-, and alpha -irradiated metals using thin film electron transmission microscopy. The quenched copper and aluminum contain dislocation loops of the order of a few hundred angstroms diameter formed by the condensation of vacancies, while the alpha -irradiated metal contains small cavities. Some additional electron microscopic studies of quenched silver and gold are also mentioned and the results discussed in relation to the mechanical and physical properties of quenched metals. No direct evidence has yet been found in neutron- irradiated copper (because of the difficulties in electropolishingl, but the small-angle scattering when considered with mechanical property measurements strongly suggests the existence of small "regions" , hardness, 100 A diameter. Direct observation of "damages" in neutron-irradiated alunium is observed, however, and shows the existence of dislocation loops, "jogged" dislocations, and "spiral" dislocations in agreement with theoretical predictions. (auth) l3985 The scattering of x rays at small angles from polycrystalline copper is found to increase when the recrystallized metal is bombarded with fast neutrons. The observed effects above 2 are due to double Bragg reflections; below about 1 1/2 they can be explained in terms both of double reflections and "truer" small-angle scattering. The results indicate that either small coherent regions (of diameter about 100 A) or severe strains are present in the irradiated metal. The results are consistent with other measurements (particularly of mechanical properties) on irradiated metals. (autb) l3986 Twelve papers are presented in this volume. They cover the subjects of dosimetry, irradiation facilities and techniques, and studies on radiation effects. (W L. H.)|
|Learning Resource Type||Article|
|Publisher Department||Atomic Energy Research Establishment, Harwell, Berks, Eng.|
|Journal||Journal of Applied Physics|
|Organization||Atomic Energy Research Establishment, Harwell, Berks, Eng.|
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