The strength-toughness combination of the aluminum-lithium alloys 2090 and 2091 at cryogenic temperatures

Technical Report · Sat Jul 01 04:00:00 EDT 1989

DOI:https://doi.org/10.2172/5684550· OSTI ID:5684550

Glazer, J.

The strength-toughness combination of the aluminum-lithium alloys 2090 (nominal composition Al-2.7 Cu-2.2 Li-0.1 Zr in wt %) and 2091 (Al-2.2 Cu-2.0 Li-1.5 Mg-0.1 Zr) plate at cryogenic temperatures was investigated. Aluminum-lithium alloys have lower density and higher stiffness than conventional aluminum alloys and were developed for aircraft applications. This study was motivated by the possibility of using aluminum-lithium alloys for cryogenic tankage of spacecraft, an application in which light weight, weldability and good cryogenic mechanical properties are at a premium. Alloy 2090-T81 has a strength-toughness combination that improves with decreasing temperature between 300 and 4 K under some conditions. This improvement is accompanied by an increase in the tensile elongation and strain hardening rate, but the large increase in fracture toughness is not reflected in the primary fracture mode. The goal of this study was to develop an understanding of the mechanisms responsible for the increase in fracture toughness at cryogenic temperatures. The mechanical properties of alloy 2090 in other metallurgical conditions and a second alloy, 2091, were also considered. Several mechanisms for interpreting the increased toughness in in-plane orientations at low temperatures were considered.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5684550
• Report Number(s): LBL-27607; ON: DE90001425
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM BASE ALLOYS
COPPER ALLOYS
CRYSTAL STRUCTURE
ELASTICITY
EMBRITTLEMENT
FAILURES
FRACTURES
HARDENING
LITHIUM ALLOYS
MAGNESIUM ALLOYS
MECHANICAL PROPERTIES
STRAIN HARDENING
TENSILE PROPERTIES
ULTRALOW TEMPERATURE
WELDABILITY