SEDL / STP / STP1172-EB / STP24714S

Aluminum-Lithium Alloys: Evaluation of Fracture Toughness by Two Test Standards, ASTM Method E 813 and E 1304

Purtscher, PT
Materials research engineer, physical scientist, and materials research engineer, National Institute of Standards and Technology, Boulder, CO

McColskey, JD
Materials research engineer, physical scientist, and materials research engineer, National Institute of Standards and Technology, Boulder, CO

Drexler, ES
Materials research engineer, physical scientist, and materials research engineer, National Institute of Standards and Technology, Boulder, CO

Pages: 21    Published: Jan 1992

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Abstract

Fracture toughness of three aluminum-lithium alloys and Alloy 2219 (a total of nine different plates) was measured with two different types of specimens and methods: (1) compact specimens using ASTM E 813 and (2) chevron-notched short-bar specimens using ASTM E 1304. The properties were measured in two orientations (T-L and L-T) and at three temperatures (295,76, and 4 K). In general, the short-bar specimens exhibited a higher fracture toughness than the compact specimens. The difference between the two procedures was relatively constant, independent of test orientation and strength. However, when the specimens exhibited extensive delaminations on the fracture surface, the compact specimens had a higher fracture toughness than the short bar specimens. The difference in fracture toughness measured by the two procedures is explained in terms of the alloys' crack growth behavior.