Evaluation of a Diffusion/Trapping Model for Hydrogen Ingress in High-Strength Alloys.

Abstract

This report covers work performed during the first year of a program to apply a diffusion/trapping model for hydrogen ingress in three high-strength alloys, AISI 4340 steel, Monel K500, and MP35N. The model is coupled to the use of a potentiostatic double-pulse technique, and current transient data were obtained for the alloys in 1 M HAc/1 M NaAc (Ac = acetate) with 15 ppm AS2O3. In all cases, the anodic charge can be analyzed as a function of charging time in terms of an interfacial control model in which the rate of H ingress into the metal is determined by the flux across the metal surface. The 4340 steel was tested at yield strengths of approximately 175 and 250 ksi. The rate constant for irreversible trapping, k, was evaluated from the measured or apparent rate constant, ka, by estimating the effect of reversible traps from diffusivity data and was found to be 4/s for both 4340 specimens. Keywords: Steel; Monel; Hydrogen; Ingress; Models; Diffusion; Trappping; High strength; Alloys; Hydrogen embrittlement.

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Document Details

Document Type
Technical Report
Publication Date
May 14, 1987
Accession Number
ADA181206

Entities

People

  • Bruce G. Pound

Organizations

  • SRI International

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Alloys
  • Chemical Composition
  • Crystal Structure
  • Data Acquisition
  • Data Analysis
  • Diffusion
  • Diffusivity
  • Electrodes
  • Elements
  • Embrittlement
  • Equations
  • Heat Treatment
  • High Strength Alloys
  • Hydrogen Embrittlement
  • Materials
  • Models
  • Yield Strength

Fields of Study

  • Materials science

Readers

  • Electrochemical Engineering/ Fuel Cell Technologies
  • Materials Science and Engineering.