Study of grain boundary segregation using the Auger electron emission technique. Annual Technical Progress Report January 1, 1979-December 31, 1979
The influence of grain boundary chemical composition on hydrogen embrittlement was investigated. Auger electron spectroscopy was employed to determine the grain boundary compositions of nickel-copper alloys containing various concentrations of phosphorus and subjected to various thermal treatments. Phosphorus segregates to grain boundaries during slow cooling, accompanied by reduced concentrations of grain boundary copper. Tensile tests were conducted in air and following cathodic charging with hydrogen. All samples tested in air exhibited a completely ductile fracture; ductility was insensitive to grain boundary composition. Fractures of hydrogen-charged samples were brittle and intergranular; elongation to fracture increased significantly with increasing concentration of grain boundary phosphorus. The influence of phosphorus segregation on embrittlement by hydrogen or by mercury (reported previously) is analyzed in terms of additive and interactive mechanisms. A mechanism based on reduced embrittler concentration at the site of bond rupture due to improved atomic packing is proposed and found to be consistent with the experimental results of this and other investigations.
- Research Organization:
- Michigan Technological Univ., Houghton (USA). Dept. of Metallurgical Engineering
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AS02-76ER02166
- OSTI ID:
- 5316246
- Report Number(s):
- DOE/ER/02166-26
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CHEMICAL COMPOSITION
COPPER ALLOYS
CRYSTAL STRUCTURE
ELEMENTS
EMBRITTLEMENT
GRAIN BOUNDARIES
HYDROGEN EMBRITTLEMENT
IRON ALLOYS
MANGANESE ALLOYS
MICROSTRUCTURE
MONEL 400
NICKEL ALLOYS
NICKEL BASE ALLOYS
NONMETALS
PHOSPHORUS
PHOSPHORUS ADDITIONS
SEGREGATION