Accession Number : AD0785020

Title :   Observations on the Stress Corrosion Cracking of an Al-5%Zn-2.5%MG Ternary and Various Quarternary Alloys,

Corporate Author : MARTIN MARIETTA LABS BALTIMORE MD

Personal Author(s) : Green,J. A. S. ; Montague,W. G.

Report Date : AUG 1974

Pagination or Media Count : 29

Abstract : Studies were undertaken to test a concept of controlling stress-corrosion crack propagation in Al-Zn-Mg alloys through the use of minor alloying additions of elements known to retard hydrogen ion recombination such as Cd, As, Zr and Cr. Results indicated that the concept was invalid since the minor alloying additions themselves exerted a more profound influence on the grain boundary microstructure. Specifically, the microstructural features of grain boundary particle size and interparticle spacing were found to correlate with stress corrosion susceptibility. Auger electron spectroscope studies also revealed a correlation between the concentration of Zn and Mg within the precipitate-free zone and the susceptibility to cracking. (Modified author abstract)

Descriptors :   *Stress corrosion, *Aluminum alloys, Crack propagation, Magnesium alloys, Zinc alloys, Hydrogen, Grain boundaries, Cadmium, Arsenic, Zirconium, Chromium, Impurities

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE