1. Scope

1.1 This test method covers procedures and guidelines for the determination of fracture toughness of metallic materials using the following parameters: K, J , and CTOD (). Toughness can be measured in the R -curve format or as a point value. The fracture toughness determined in accordance with this test method is for the opening mode (Mode I) of loading.

1.2 The recommended specimens are single-edge bend, [SE(B)], compact, [C(T)], and disk-shaped compact, [DC(T)]. All specimens contain notches that are sharpened with fatigue cracks.

1.2.1 Specimen dimensional (size) requirements vary according to the fracture toughness analysis applied. The guidelines are established through consideration of material toughness, material flow strength, and the individual qualification requirements of the toughness value per values sought.

1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Other standard methods for the determination of fracture toughness using the parameters K, J , and CTOD are contained in Test Methods E 399, E 813, E 1152, E 1290, and E 1737. This test method was developed to provide a common method for determining all applicable toughness parameters from a single test.

1.4 This annex covers the determination of the rate dependent J Ic (t) and the J -integral versus crack growth resistance curve ( J-R(t) curve) for metallic materials under conditions where the loading rate exceeds that allowed for conventional (static) testing, see Section .

1.5 The normalization technique can be used in some cases to obtain a J-R curve directly from a force displacement record taken together with initial and final crack size measurements taken from the specimen fracture surface. Additional restrictions are applied (see A14.1.3) which limit the applicability of this method. The normalization technique is described more fully in Herrera and Landes ( ) and Landes, et al. ( ), Lee ( ), and Joyce ( ). The normalization technique is most valuable for cases where high loading rates are used, or where high temperatures or aggressive environments are being used. In these, and other situations, unloading compliance methods are impractical. The normalization method can be used for statically loaded specimens if the requirements of this section are met. The normalization method is not applicable for low toughness materials tested in large specimen sizes where large amounts of crack extension can occur without measurable plastic force line displacement.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

E4 Practices for Force Verification of Testing Machines

E8/E8M Test Methods for Tension Testing of Metallic Materials

E21 Test Methods for Elevated Temperature Tension Tests of Metallic Materials

E23 Test Methods for Notched Bar Impact Testing of Metallic Materials

E399 Test Method for Linear-Elastic Plane-Strain Fracture Toughness K Ic of Metallic Materials

E1290 Test Method for Crack-Tip Opening Displacement (CTOD) Fracture Toughness Measurement

E1823 Terminology Relating to Fatigue and Fracture Testing

E1921 Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range

E1942 Guide for Evaluating Data Acquisition Systems Used in Cyclic Fatigue and Fracture Mechanics Testing

E2298 Test Method for Instrumented Impact Testing of Metallic Materials

Keywords

crack initiation; crack-tip opening displacement; CTOD; ductile fracture; elastic-plastic fracture toughness; fracture instability; J-integral; K Ic ; plane-strain fracture toughness; resistance curve; stable crack growth;

ICS Code

ICS Number Code 77.040.10 (Mechanical testing of metals)

DOI: 10.1520/E1820-06

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