Hydrogen Embrittlement of a Cyclically Deformed High Strength Al Alloy.
Abstract
High cycle fatigue experiments have been performed on a 7075 Al alloy, principally in the T6 temper in dry air, distilled water 0.5N NaCl and 0.5N Na2SO4 solutions as functions of pH, cathodic charging and catalyst poisoning of the hydrogen evolution reaction. All aqueous solutions appreciably lowered fatigue resistance with Cl(-) ion producing the greatest reduction in resistance and SO4(=) ion behaving essentially in the same manner as distilled water. Under cathodic charging conditions fatigue resistance is significantly reduced and both Cl(-) and SO4(=) solutions produce similar fatigue lives. Acid solutions reduce fatigue resistance to a greater degree than do basic solutions of equivalent corrosivity and a catalyst poison (As) added to Cl(-) solutions reduces fatigue resistance relative to neutral Cl(-) solutions. Fractography of specimens fatigued in aqueous environments shows that a significant amount of cleavage and quasi-cleavage occurs, the extent of these features being apparently a function of available hydrogen to the alloy free surface and to the tips of growing cracks.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1976
- Accession Number
- ADA035135
Entities
People
- D. J. Duquette
- R. J. Jacko
Organizations
- Rensselaer Polytechnic Institute