Determining Ductile Fracture Toughness in Metals

Journal Article · Wed Jan 01 04:00:00 EST 2014 · Advanced Materials and Processes

OSTI ID:1126963

Chen, Xiang ^[1]; Nanstad, Randy K ^[1]; Sokolov, Mikhail A ^[1]; Manneschmidt, Eric T ^[1]

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1. ORNL

Ductile fracture toughness determination, such as the J-integral versus crack growth resistance (J-R) curve, is a useful tool for evaluating material structural integrity in the presence of pre-existing defects. The J-R curve represents a way to calculate the work (energy) per unit fracture surface area needed to drive the crack growth. A typical J-R curve is shown in Fig. 1 from which the material fracture toughness near the initiation of stable crack growth (Jq) can be derived. In addition, tearing modulus (TR), representing the material resistance to stable crack growth, can be calculated based on the slope of the J-R curve between two exclusion lines (red dashed lines in Fig. 1). Since the introduction of the J-R curve, extensive efforts have been continuously devoted to develop simplified and reliable methods for determining the material J-R curve. This article briefly reviews three widely-used J-R curve test methods in metals, i.e. elastic unloading compliance (EUC), normalization, and direct current potential drop (DCPD). The main difference in these methods relates to the determination of the crack size. More details of performing the J-R curve determination can be found in ASTM standard E1820-11.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1126963
• Journal Information: Advanced Materials and Processes, Journal Name: Advanced Materials and Processes Journal Issue: 04 Vol. 172
• Country of Publication: United States
• Language: English

Related Subjects

DCPD
Elastic Unloading Compliance
Fracture Toughness
J-R curve
Normalization