1.1This practice is applicable to the fracture toughness testing of all aluminum alloys, tempers, and products, especially in cases where the tests are being made to establish whether or not individual lots meet the requirements of specifications and should be released to customers.

1.2Test Method E399 is the basic test method to be used for plane-strain fracture toughness testing of aluminum alloys. The purpose of this practice is to provide supplementary information for plane-strain fracture toughness of aluminum alloys in three main areas:

1.2.1Specimen sampling,

1.2.2Specimen size selection, and

1.2.3Interpretation of invalid test results.

1.3The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3.1Exception-Certain inch-pound values given in parentheses are provided for information only.

1.4This standard is currently written to accommodate only C(T) specimens.

1.5This 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.