Metallurgical Transactions

, Volume 5, Issue 6, pp 1285–1294 | Cite as

The mechanical nature of stress-corrosion cracking in Al-Zn-Mg alloys: I. Evaluation of the ductile rupture contribution

  • W. E. Wood
  • W. W. Gerberich
Physical Chemistry
Received:

Abstract

A detailed study of rapid stress-corrosion-cracking (SCC) in a 7075 aluminum alloy has allowed separation of the mechanical and chemical contributions. This was accomplished by combining scanning electron microscopy, stress-wave emission and crack growth rate observations as a function of test temperature. These established an activation energy of 11.2 kcal/mol, a stress-intensity squared dependence of crack growth, and a range of 20 to 80 pct dimpled rupture on the fracture surfaces. Thus a two-step crack growth mechanism is proposed combining a thermally activated electrochemical process and a discontinuous mechanical jumping process.

Keywords

Crack Growth Rate Stress Wave Slow Crack Growth Precipitate Free Zone Dimple Rupture 
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Copyright information

© American Society for Metals, The Melallurgical Society of AIME 1974

Authors and Affiliations

  • W. E. Wood
    • 1
  • W. W. Gerberich
    • 2
  1. 1.Dept. of Materials ScienceOregon Graduate CenterBeaverton
  2. 2.Dept. of Chemical Eng. and Materials ScienceUniversity of MinnesotaMinneapolis

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