Influence of multiaxial stresses on creep properties of phosphorus alloyed oxygen free copper
2010 (English)In: Proceedings Of The ASME Pressure Vessels And Piping Conference 2009, ASME Press, 2010, no PART B, 1525-1532 p.Conference paper (Refereed)
Phosphorus alloyed oxygen free copper (Cu-OFP) canisters are planned to be used for spent nuclear fuel in Sweden. The copper canisters will be subjected to creep under multiaxial stress states in the repository. Creep tests have therefore been carried out using double notch specimens having a notch acuity of 0.5 in Cu-OFP at 75°C. The creep results from the notched specimens are compared with those from the smooth ones. It shows that the creep lifetime for notched specimens can be estimated to be two orders of magnitude or more longer than that for the smooth ones, indicating notch strengthening for the investigated Cu-OFP material. Metallographic examinations after failure show that pores and creep cavities to a limited extent are observed only adjacent to fracture. To interpret the tests for the notched creep specimens, finite element computations have been performed with a new basic model for primary creep without fitting parameters. The creep strain versus time could be simulated successfully. Initially the stresses at the notches are almost twice as high as in the centre of the specimens. The highest stresses are relaxed rapidly. At the studied temperature 75°C, the creep exponent of Cu-OFP is about 85, thus, deep down in the power-law breakdown regime. This contributes strongly to the homogenous stress distribution across the centre section. Since the redistribution of stresses has taken place before large creep deformation has occurred, the specimens are not notch sensitive in agreement with observations.
Place, publisher, year, edition, pages
ASME Press, 2010. no PART B, 1525-1532 p.
, American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP, ISSN 0277-027X ; 6
Copper, Creep, FEM, Multiaxial stresses, Notched specimens, Primary creep
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-149402DOI: 10.1115/PVP2009-77693ISI: 000280407700162ScopusID: 2-s2.0-77952999546ISBN: 978-0-7918-4369-7OAI: oai:DiVA.org:kth-149402DiVA: diva2:739471
2009 ASME Pressure Vessels and Piping Conference, 26 July 2009 through 30 July 2009, Czech Republic
QC 201408212014-08-212014-08-212014-08-21Bibliographically approved