Evaluation of a Diffusion/Trapping Model for Hydrogen Ingress in High- Strength Alloys
Abstract
Alloys developed to improve strength, weight, and corrosion resistance often remain susceptible to hydrogen embrittlement (HE). The objective of this research was to investigate hydrogen ingress in high performance alloys, particularly in terms of irreversible trapping, with a view to characterizing their susceptibility to HE. A technique referred to as hydrogen ingress analysis by potentiostatic pulsing (HIAPP) was applied to five unaged and aged B-Ti alloys (Beta-C, Ti-10-2-3, Ti-13-11-3, Ti-15-3, and Beta- 21S), an alpha-beta Ti alloy (Ti-6-4), two Cu-Ni alloys (Marinel and Monel K- 500), and a Ni-base alloy (UNS N07716). Anodic transients obtained in 1 mol/L HAc-I mol/L NaAc (Ac = acetate) were analyzed using a diffusion/trapping model to evaluate the trapping constant and hydrogen entry flux. Except for Ti-15-3, aging increases irreversible trapping in the B-Ti alloys, the increase paralleling the decrease in their tolerance to hydrogen. Ti-13-11-3 is indicated to be the most susceptible to HE, followed by Beta-21S, Beta-C, Ti-10-2-3, and Ti-153, with the trapping constants apparently being determined by the degree of grain boundary alpha phase. The trapping constants for aged Marinel and alloy K-500 do not appear to differ significantly, but a lower flux for Marinel accounts, at least partly, for its higher resistance to HE. Likewise, a low flux for alloy 716 is consistent with it generally being resistant to cracking. Beta- titanium alloys, Monel K-500, Marinel, Alloy 716, Potentiostatic pulse hydrogen trapping, Trapping model, Hydrogen ingress.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1992
- Accession Number
- ADA271328
Entities
People
- Bruce G. Pound
Organizations
- SRI International