Irradiation of metals with high‐energy particles produces nano‐scale defects that act as obstacles to dislocation glide. This paper presents the effects of low‐level neutron radiation on the stress rupture and microstructural properties of two tantalum alloys, Ta‐10%W and Ta‐8%W‐2%Hf (T‐111), which have been used to encapsulate radioactive fuel for space Radioisotope Power Systems (RPS). Ta‐10%W and T‐111 test specimens were exposed to a neutron fluence level at temperatures less than which is equivalent to the cumulative fluence associated with the 30‐year mission life of a RPS. This fluence level results in an atomic displacement damage of approximately in both alloys. The atomic displacement damage produces an approximate two‐order of magnitude increase in the stress rupture time, and a two‐order of magnitude reduction in steady state creep rate. These observations are statistically significant at the 0.05 significance level. Transmission electron microscopy of rupture specimens reveals that the interaction of the irradiation produced defects with screw dislocations results in a five‐fold increase in dislocation density and a pronouncement of the ordering of dislocations into mosaic patterns of cellular or subgranular arrangements. The results of this research are significant because they provide a basic understanding of the strength mechanisms in two tantalum alloys (Ta‐10%W and T‐111) resulting from neutron irradiation at temperatures
Investigation of Stress Rupture Tested Neutron Irradiated Tantalum Alloys
SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM‐STAIF 2008: 12th Conference on Thermophysics Applications in Microgravity; 1st Symposium on Space Resource Utilization; 25th Symposium on Space Nuclear Power and Propulsion; 6th Conference on Human/Robotic Technology and the Vision for Space Exploration; 6th Symposium on Space Colonization; 5th Symposium on New Frontiers and Future Concept ; 2008 ; Albuquerque (New Mexico)
AIP Conference Proceedings ; 969 , 1 ; 439-445
21.01.2008
7 pages
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
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