The Role of Hydrogen on Environmental Fatigue of High Strength Aluminum Alloys.
Abstract
An extensive series of experiments have been performed on a 7075 aluminum alloy and its high purity analogue, Al5Zn2.5Mg, in aqueous environments, to determine the role of cathodically evolved hydrogen on fatigue crack initiation and early propagation. Variables in the program include the effects of applied potential, hydrogen damage reversibility, solution pH and mechanical loading modes. Results obtained in the program refute the concept that anionic species need be specific to cause enhanced susceptibility to fatigue cracking, but that hydrogen, both in the presence of absence of significant corrosion, is indeed a potent species for the degradation of fatigue properties. Evidence is presented that hydrogen, presumed to be associated with the plastic zone at crack tips, causes increased crack propagation rates and also results in significant changes in fracture surface morphologies. Evidence is described which strongly suggests that the ingress of hydrogen may be related to the structure and properties of the oxide film(s) which are formed under given environmental circumstances.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 24, 1980
- Accession Number
- ADA090184
Entities
People
- D. J. Duquette
- R. J. Jacko
Organizations
- Rensselaer Polytechnic Institute