Accession Number : ADA115693

Title :   The Delayed Fracture of Aluminum Alloys, End of Year Report.

Descriptive Note : Rept. for 16 Mar 81-15 Mar 82,

Corporate Author : MARTIN MARIETTA LABS BALTIMORE MD

Personal Author(s) : Pickens,Joseph R ; Venables,David ; Davis,Guy D ; Gordon,Jonathan R

PDF Url : ADA115693

Report Date : Mar 1982

Pagination or Media Count : 48

Abstract : The mechanisms of failure of high-strength aluminum alloys in saline environments was investigated. It was found that the mechanism of stress corrosion cracking (SCC) in a commercial Al-Mg alloy, 5083, is dominated by hydrogen embrittlement (HE). The dominant contribution of HE was discerned by comparing SCC susceptibility under Modes I and III loading. The influence of the surface oxide film on the SCC susceptibility of 7075 and 7175 alloys was also examined. It was found that unlike certain high purity alloys, the susceptibility of these commercial alloys is not significantly influenced by the composition of the oxide. In these 7xxx alloys, the insoluble constituent particles provide sites for SCC initiation. The greater susceptibility of 7075, compared with its higher purity version, 7175, is in part a result of its lower value fraction of the constituent particles. (Author)

Descriptors :   *Aluminum alloys, *High strength alloys, *Fracture(Mechanics), *Stress corrosion, *Cracking(Fracturing), Hydrogen embrittlement, Bulk materials, Magnesium alloys, Zinc alloys, Oxides, Films, Grain boundaries, Test methods, Triaxial stresses, Tensile strength, Yield strength, Auger electron spectroscopy, Aging(Materials), Toughness, Solution heat treatment, Etching, Microstructure, Fractography, Surface properties, Plastic properties

Subject Categories : Properties of Metals and Alloys
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE