NEUTRON RADIATION DAMAGE IN COPPER
Copper single crystals subjected to a neutron dose of 3 x l0/sup 17/ nvt (fast flux) at pile temperatures were examined after deformation by the following experimental techniques: observation of the load-extension relationships; investigation of the slip-line structure with the electron microscope; and diffraction electron microscopy of thinned-down single crystals before and after deformation. The critical resolved shear stress was in the order of 0.16 kg/mm/ sup 2/. In the early stages of deformation, the load-extension curves showed serrations which were as large as l.0% of the critical resolved shear stress. In the linear portion of the stressstrain curve, the rate of work hardening was less for irradiated single crystals than for the nonirradiated. The stress-strain curves of the irradiated and the nonirradiated specimens were similar in the parabolic region of the curves. The slip-line structure, at low deformations, consisted of fine slip lines that were clustered together; the distances between the slip lines were, on the average, 100 A and often less; the distances between the clusters were in the order of 4 mu . The structure was quite different than the alpha-brass structure, which in the past was considered typical for irradiated copper. Cross slip, which was most abundant in the linear-hardening region of the stress-strain curve, was found to be orientation dependent. The slip-line structures for the irradiated and nonirradiated crystals at high strains were very similar. Prismatic dislocation loops, apparently resulting from the agglomeration of vacancies, were found to be the most frequently produced radiation defect. The interaction between loops and glide dislocations resulted in heavily kinked dislocations which were probably responsible for the observed high yield stress. The glide dislocations were seen to remove the radiation damage. Because of the cleaning out of radiation-produced defects and the ability of the dislocations to multiply from new sources, the prolonged easy- glide range can be explained. Further, the proposed mechanism provided an explanation of the work hardening in the linear and parabolic parts of the stressstrain curve. (Dissertation Abstr., 23: No. 4, 1962)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-17-005024
- OSTI ID:
- 4752176
- Resource Relation:
- Other Information: Thesis. Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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