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Reuter, A. M. Porter, N. M. CarisonIdaho National Engineering Laboratory, Lockheed Idaho Technologies CompanyP.O. Box 1625, Idaho Falls, Idaho 83415-2218ABSTRACTThermal embrittlement, which can occur during normal operating conditions, may reduce the fracture toughness ofmaterials to the point that structural integrity becomes suspect. Much of the data reported in the literature is based onusing impact energy to quantify the extent of embrittlement experienced by base metal specimens. These data provide auseful, qualitative description of the embrittlement but are of limited use in predicting structural integrity when there arecracks in the base metal or in weidments. This paper presents fracture toughness data for both base metal and weidmentsexposed at 649°C for times up to 5000 h. In addition, preliminary results are provided regarding the use of nondestructiveexamination (NDE) techniques to predict changes in fracture toughness.Keywords: thermal embrittlement, fracture toughness, Alloy 7 1 8 base metal, weldments, NDE |
