Characterization of hydrogen ingress in high-strength alloys. Final report, 15 September 1993-14 September 1995
The ingress of hydrogen (H) in various high-strength alloys was investigated with a view to characterizing their susceptibility to hydrogen embrittlement (HE). A potentiostatic pulse technique was applied to three Fe-base alloys (AerMet 100, H11, and A-286), two Cu-containing alloys (Be-Cu and alloy K-500), a superferritic stainless steel (Sea-Cure), and three Beta-Ti alloys (Ti-15V-3Cr-3Al-3Sn, Beta-21S, and Beta-C) in 1 mol/L acetic acid-1 mol/L sodium acetate. The data were analyzed using a diffusion/trapping model to obtain the irreversible trapping constant (k) and H entry flux for each alloy. The order of the k values for AerMet 100, H11, and two high-strength steels previously studied (4340 and 18Ni) inversely parallels their threshold stress intensities for stress corrosion cracking. Likewise, the k values for the other alloys can be correlated with their observed resistances to HE according to the following groups: (1) alloy A-286,18Ni steel, H11, Be-Cu, and also alloy 718 from earlier work; (2) annealed/aged and direct aged alloy K-500; and (3) Ti alloys. The trapping characteristics of Sea-Cure could not be determined. However, the propensity of the S44660 alloy to undergo HE at cathodic protection potentials can be attributed to changes in the oxide that lead to a less restricted entry of H.
- Research Organization:
- SRI International, Menlo Park, CA (United States)
- OSTI ID:
- 229253
- Report Number(s):
- AD-A--302136/7/XAB; CNN: Contract N00014-91-C-0263
- Country of Publication:
- United States
- Language:
- English
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