ISSN: 1945-7553
CODEN: JTEVAB
Page Count: 11

A Procedure for Fracture Toughness Testing Using a Chevron-Notched Crack-Arrest Specimen

Bonenberger, RJ
Materials scientist, FM Technologies, Inc., Fairfax, VA

Dally, JW
Independent consultant, Knoxville, TN

Fourney, WL
Professor and interim chairman, University of Maryland, College Park, MD

(Received 3 February 1997; accepted 9 December 1997)

Abstract

A new chevron-notched crack-arrest (CNCA) specimen has been developed for determining the fracture toughness of metals in a more cost-effective manner. The specimen is a hybrid design that incorporates features from the standard K_Ic and K_Ic specimens. Details of the specimen geometry and associated test procedures are described. Strain gages record the stress state in the specimen, and a clip gage measures the crack mouth opening displacement. The method for extracting arrest and initiation toughness from the measured data is presented. Fracture experiments using the CNCA specimen ware conducted to determine K_a and K_c for A533-B reactor grade steel at 23°C. The K_a and K_c results from this study were consistent with similar data established for the same material by other-researchers. A fractographic analysis identified cleavage as the dominant failure mode during crack propagation, with a conversion to ductile tearing just before arrest.

Keywords:
fracture, fracture toughness, crack arrest testing, chevron notch, steel (reactor grade)

Paper ID: JTE12016J
DOI: 10.1520/JTE12016J
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