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U.S. Department of Energy
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EFFECT OF CREEP-EXPOSURE ON MECHANICAL PROPERTIES OF RENE 41

Technical Report ·
OSTI ID:4802537
BS>Rene 4l was tensile tested at room temperature after creep-exposure or unstressed exposures of 10 to 200 hours at temperatures between 1200 deg and 1800 deg F. Thermallyinduced structural changes reduced strength and ductility after exposures above l500 deg F, while creep strains caused inereased strength and decreased ductility after lower temperatures. Limited data indicated that surface reactions reduced properties in addition to the effects of the creep- exposures. Creep accelerated structural changes and raised yield strength by a Bauschtnger effect. Ductility was reduced more after creep than by thermallyinduced changes. At 1200 deg and 1300 deg F, creep strains approaching the ultimate ductility induced deep cracking. This effect was not found at higher temperatures. The loss in strength from thermal changes appeared to be due to the overaging of the gamma prime precipitate, while losses in ductility were associated with buildup of carbides and agglomeration of gamma prime at the grain boundaries. Surface effects were associated with intergranular oxidation, cracking, and alloy depletion. The role of creep needs further clarification and further study of surface reactions is needed before general principles can be formulated for the influence of creep-exposure on normal temperature mechanical propertie s. (auth)
Research Organization:
Michigan. Univ., Ann Arbor
NSA Number:
NSA-16-010503
OSTI ID:
4802537
Report Number(s):
ASD-TR-61-73
Country of Publication:
United States
Language:
English