SYMPOSIA PAPER Published: 12 May 2015
STP158420140057

Application of Direct Current Potential Drop for the J-Integral vs. Crack Growth Resistance Curve Characterization

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The dc potential drop (DCPD) technique has been applied to derive the J-integral versus crack growth resistance curve (J–R curve) for fracture toughness characterization of structural materials. The test matrix covered three materials including type 316LN stainless steels, Ni-based alloy 617, and one ferritic-martensitic steel, three specimen configurations including standard compact, single edge bend, and disk-shaped compact specimens, and temperatures ranging from 20 to 650°C. When compared with baseline J–R curves derived from the ASTM E1820-13 normalization method, the original J–R curves from the DCPD technique yielded much smaller JQ values due to the influence of crack blunting, plastic deformation, etc., on potential drop. To compensate these effects, a new procedure for adjusting DCPD J–R curves was proposed. After applying the new adjustment procedure, the average difference in JQ between the DCPD technique and the normalization method was only 5.2 % and the difference in tearing modulus was 7.4 %. These promising results demonstrate the applicability of the DCPD technique for J–R curve characterization especially in extreme environments, such as elevated temperatures, where the conventional elastic unloading compliance method faces considerable challenges.

Author Information

Chen, Xiang (Frank)
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, US
Nanstad, Randy
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, US
Sokolov, Mikhail
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, US
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Details
Developed by Committee: E08
Pages: 97–112
DOI: 10.1520/STP158420140057
ISBN-EB: 978-0-8031-7614-0
ISBN-13: 978-0-8031-7613-3