An iridium alloy, DOP‐26, is used as cladding for 238PuO2 fuel in radioisotope heat sources for space power systems. Presently, DOP‐26 iridium alloy clad vent sets (CVS) are being manufactured at the Oak Ridge Y‐12 Plant for potential use in the National Aeronautics and Space Administration’s Cassini mission to Saturn. Wrought/ground/stress relieved blanks are warm formed into CVS cups. These cups are then annealed to recrystallize the material for subsequent fabrication/assembly operations as well as for final use. One of the cup manufacturing certification requirements is to test for Vickers microindentation hardness. New microindentation hardness specification limits, 210 to 310 HV, have been established for a test load of 1000 grams‐force (gf). The original specification limits, 250 to 350 HV, were for 200 gf testing. The primary reason for switching to a higher test load was to reduce variability in the test data. The DOP‐26 alloy exhibits microindentation hardness load dependence, therefore, new limits were needed for 1000 gf testing. The new limits were established by testing material from 15 CVS cups using 200 gf and 1000 gf loads and then statistically analyzing the data. Additional work using a Knoop indenter and a 10 gf load indicated that the DOP‐26 alloy grain boundaries have higher hardnesses than the grain interiors.
Microindentation hardness evaluation of iridium alloy clad vent set cups
10th SymposiumùSpace Nuclear Power and Propulsion ; 1993 ; Albuquerque, NM, USA
AIP Conference Proceedings ; 271 , 2 ; 1099-1105
15.01.1993
7 pages
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
Microindentation Hardness Evaluation of Iridium Alloy Clad Vent Set Cups
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