1.1 This test method covers the determination of fracture toughness (KIc) of metallic materials under predominantly linear-elastic, plane-strain conditions using fatigue precracked specimens having a thickness of 1.6 mm (0.063 in.) or greater subjected to slowly, or in special (elective) cases rapidly, increasing crack-displacement force. Details of test apparatus, specimen configuration, and experimental procedure are given in the Annexes.
Plane-strain fracture toughness tests of thinner materials that are sufficiently brittle (see ) can be made using other types of specimens (). There is no standard test method for such thin materials.
1.2 This test method is divided into two parts. The first part gives general recommendations and requirements for KIc testing. The second part consists of Annexes that give specific information on displacement gage and loading fixture design, special requirements for individual specimen configurations, and detailed procedures for fatigue precracking. Additional annexes are provided that give specific procedures for beryllium and rapid-force testing.
1.3 General information and requirements common to all specimen configurations:
Plane-Strain Fracture Toughness
Crack Plane Orientation
Summary of Test Method
Significance and Use
Apparatus (see also )
Displacement Gage, Measurement
Specimen Size, Configurations, and Preparation (see also )
Specimen Size Estimates
Standard and Alternative Specimen Configurations
Fatigue Crack Starter Notches
Fatigue Precracking (see also )
Crack Extension Beyond Starter Notch
Crack Plane Angle
Calculation and Interpretation of Results
Test Record Analysis
Pm ax/PQ Validity Requirement
Specimen Size Validity Requirements
Precision and Bias
1.4 Specific requirements related to test apparatus:
Double-Cantilever Displacement Gage
Bend Specimen Loading FixtureAnnex
Compact Specimen Loading ClevisAnnex
1.5 Specific requirements related to individual specimen configurations:
Bend Specimen SE(B)
Compact Specimen C(T)
Disk-Shaped Compact Specimen DC(T)
Arc-Shaped Tension Specimen A(T)
Arc-Shaped Bend Specimen A(B)
1.6 Specific requirements related to special test procedures:
Fatigue Precracking KIc Specimens
Hot-Pressed Beryllium Testing
1.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.8 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.