POINT DEFECT HARDENING IN FACE-CENTERED CUBIC METALS
The re-examination of presently available experimental evidence leads to the conclusion that discolorations differ in the ability to absorb or emit point defects by climb. Old dislocations, namely those which have been stationary during aging or annealing treatments, are not easy sources or sinks of vacancies, while new dislocations, i.e. dislocations which have moved during or since annealing treatments, are easy sources and sinks. Further differences exist in the interactions between point defects and dislocations of edge and screw type, and between mixed dislocations of different orientations, as well as between stationary or slowly moving and fast moving dislocations. The major experimental results on the phenomenon of quench hardening reflect the multiplicity of types of interactions between dislocations and vacancies. Possible explanations are given for the peculiar tangles consisting of kinked and intertwined dislocations often found in face-centered cubic (fcc) metals, for the generation of small dislocation loops in deformed annealed material as well as their partial elimination in quenched or irradiated specimens, for the typical slip line structure, and for the occurrence of overshooting in quenched or irradiated material. Quenched or irradiated pure fcc metals are obviously greatly affected by the presence of vacancies in supersaturation. On the other hand, it is known that point defects are generated during slip, and also that, for deformed fcc pure metals, the dislocation configurations in both types of specimens are quite similar to each other. The conclusion is that the plastic behavior of annealed pure fcc metals and single crystals is also greatly influenced by vacancies and that theories of the plastic properties of metals must take this into consideration. It is further believed that the different mechanisms of interactions between point defects and dislocations play an important role in metal fatigue. (auth)
- Research Organization:
- Pennsylvania. Univ., Philadelphia. School of Metallurgical Engineering; Franklin Inst. Labs. for Research and Development, Philadelphia
- NSA Number:
- NSA-15-017320
- OSTI ID:
- 4036710
- Report Number(s):
- TID-11768
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-61
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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