THE EFFECT OF MICROSTRUCTURE ON THE STRESS-CORROSION SUSCEPTIBILITY OF AN A1-Zn-Mg ALLOY

Abstract

The effect of microstructure on the susceptibility of a high purity Al-6.8% Zn-2.3% Mg alloy to stress-corrosion cracking in an aqueous salt solution (3.5 wt % NaCl) was studied. The results of testing a series of specimens having controlled microstructures and the same yield strength of 40, 000 psi indicate that the susceptibility to stress-corrosion is controlled by the type, size, and spacing of the matrix precipitate through the effect of these precipitates on the deformation process. Although the width of the precipitate free zone appears to have no effect on susceptibility, the grain boundary precipitate seems to influence susceptibility in certain cases. Supporting evidence for these observations was obtained by light and electron microscopic examinations of deformed specimens and by fractographic studies. A model is proposed which explains many experimental observations.

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Document Details

Document Type
Technical Report
Publication Date
Feb 01, 1970
Accession Number
AD0702691

Entities

People

  • A. J. Deardo Jr.
  • R. D. Townsend

Organizations

  • Carnegie Mellon University

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Boundaries
  • Chemistry
  • Crystal Structure
  • Electron Microscopy
  • Grain Boundaries
  • Heat Treatment
  • Materials
  • Materials Science
  • Mechanical Properties
  • Microscopes
  • Microscopy
  • Solid Solutions
  • Stress Corrosion
  • Stress Corrosion Cracking
  • Tensile Properties
  • Tensile Strength
  • Yield Strength

Fields of Study

  • Materials science

Readers

  • Materials Science (Mechanical Engineering).
  • Powder metallurgy of Titanium alloys.

Technology Areas

  • Microelectronics
  • Space