On the Chemistry of the Solution at the Tips of Stress-Corrosion Cracks in Aluminum Alloys.
Abstract
A study was made of the factors affecting the change of pH with time of initially acidic (pH = 0 to 2) 3% NaCl solutions, resulting from the dissolution of turnings of a commercial 7075 alloy, an Al-5.3 wt. pct. Zn-2.5 wt. pct. Mg alloy, and pure aluminum. It was shown that for solutions containing large volume fractions of the solids, a steady pH is attained which is associated with the onset of precipitation of Al(OH)3. It is suggested, by analogy, that the formation of the steady pH region at the tips of stress-corrosion cracks in aluminum alloys is also associated with the onset of precipitation of Al(OH)3, and that the pH in this region can be calculated from the solubility product of freshly precipitated Al(OH)3. The study also suggests that similar conclusions apply to the stress-corrosion cracking of magnesium alloys. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1970
- Accession Number
- AD0716480
Entities
People
- A. J. Sedriks
- D. L. Novak
- J. A. S. Green
Organizations
- Martin Marietta