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

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)

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1990
Accession Number
ADA222803

Entities

People

  • John J. Ruschau
  • Kumar V. Jata

Organizations

  • University of Dayton

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Aluminum Alloys
  • Classification
  • Failure Mode And Effect Analysis
  • Grain Boundaries
  • Liquid Oxygen
  • Materials
  • Materials Engineering
  • Materials Laboratories
  • Materials Science
  • Mechanical Properties
  • Orientation (Direction)
  • Resistance
  • Security
  • Strain Hardening
  • Tensile Properties
  • Tensile Strength
  • Tensile Testing

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Reinforced Composite Materials