Accession Number:

ADA222803

Title:

Fracture Toughness and Failure Mechanisms in Commercial 2091 A1-Li Sheet at Cryogenic Temperatures

Descriptive Note:

Interim rept. Jul 88-Dec 89,

Corporate Author:

DAYTON UNIV OH RESEARCH INST

Personal Author(s):

Report Date:

1990-03-01

Pagination or Media Count:

46.0

Abstract:

Strength-toughness relationships in 2091 Al-Li Aluminum-Lithium alloy in the T3 temper were examined at ambient, liquid nitrogen and liquid helium temperatures as a function of sheet orientation and product form sheet thickness. Commercially available 1.6 millimeters 0.063 inch and 3.6 millimeters 0.144 inch thick sheets in the T3 temper were examined, with both alloy sheets exhibiting increasing yield strength but decreasing tensile elongation and toughness at cryogenic temperatures in all orientations. This behavior is in contrast with the observation of enhanced strength and toughness in longitudinal and transverse orientations L-T and T-L and certain heat treatment tempers of 2090 and 8090 Al-Li alloys at cryogenic temperatures. It is also noted that in the present 2091 sheets where the triaxial state of stress is expected to be low, through thickness delaminations are prevalent at cryogenic temperatures due to weak short transverse properties. Keywords Aluminum-lithium, 2091-T3, Sheet, Fracture toughness, Cryogenic temperatures, Tensile, Mechanical properties, Fracture mechanisms, Alloys. jg

Subject Categories:

  • Properties of Metals and Alloys

Distribution Statement:

APPROVED FOR PUBLIC RELEASE