Accession Number : ADA302136

Title :   Characterization of Hydrogen Ingress in High-Strength Alloys.

Descriptive Note : Final rept. 15 Sep 93-14 Sep 95,

Corporate Author : SRI INTERNATIONAL MENLO PARK CA

Personal Author(s) : Pound, Bruce G.

PDF Url : ADA302136

Report Date : NOV 1995

Pagination or Media Count : 107

Abstract : 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. jg p2

Descriptors :   *SODIUM, *HIGH STRENGTH ALLOYS, *HYDROGEN, *ACETATES, THRESHOLD EFFECTS, CRACKS, INTENSITY, STAINLESS STEEL, VOLTAGE, CARBON, ALLOYS, PULSES, COPPER, NICKEL, TITANIUM, IRON ALLOYS, BERYLLIUM, SULFUR, CATHODIC PROTECTION, HYDROGEN EMBRITTLEMENT, POTENTIOSTATIC TECHNIQUES, STRESS CORROSION, BASE METAL, CATHODES(ELECTROLYTIC CELL).

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE