ASTM E399 – Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness KIc of Metallic Materials
This test method determines the plane-strain fracture toughness (KIc) of metallic materials. Fracture toughness (KIc) is the stress intensity factor at the crack tip for when the crack becomes unstable and failure occurs. Depending on the strength, ductility and toughness level of the material, KIc is determined within linear elastic fracture mechanics limits. If the material is highly ductile, then the JIc test method should be performed, ASTM 813/1820.