Influence of Beryllides on the Corrosion of Commercial Grades of Beryllium

ABSTRACTCommercially available Be is generally a powderprocessed material. The powder is produced by the comminution of ingots, grinding and milling. The resulting powder has a high surface area that manifests itself in the final product as beryllium oxide (BeO) inclusions; powder products typically...

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Bibliographic Details
Published in:Corrosion (Houston, Tex.) Tex.), 2003-05, Vol.59 (5), p.424-435
Main Authors: Hill, M.A., Hanrahan, R.J., Haertling, C.L., Schulze, R.K., Lillard, R.S.
Format: Article
Language:English
Subjects:
Alloying elements
Ambient temperature
Analytical methods
Applied sciences
Beryllides
Beryllium
Circuits
Corrosion
Corrosion mechanisms
Electric arc melting
Electrochemistry
Exact sciences and technology
Intermetallic compounds
Iron
Melting
Metals. Metallurgy
Oxide coatings
pH effects
Photoelectron spectroscopy
Photoelectrons
Submerging
Titanium
X ray photoelectron spectroscopy
X rays
X-ray diffraction
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Summary:ABSTRACTCommercially available Be is generally a powderprocessed material. The powder is produced by the comminution of ingots, grinding and milling. The resulting powder has a high surface area that manifests itself in the final product as beryllium oxide (BeO) inclusions; powder products typically contain >0.50 wt% BeO. In addition to the relatively high BeO content, most impurity concentrations in commercial Be exceed the solubility limit and produce precipitates. Typical compositions of powder-processed materials are presented in Table 1. Commercial grades, such as S200F and S200D, are characterized by a high level of Fe and Al impurity in addition to trace levels of Ti. These impurities are present as both binary and ternary intermetallic phases with Be. The ternary intermetallic FeAlBe4 is a Laves phase and has the MgCu2-type structure (a = 6.06 Å). This beryllide is present in most wrought forms of Be. This phase dissolves at 850°C and can reprecipitate upon aging.1 The presence of FeAlBe4 is associated with increased cracking tendencies when welding Be.2 Both room and elevated temperature properties decrease with increasing FeAlBe4 precipitation.3 If there is insufficient Al to form the ternary, the Fe may remain in solution or precipitate out as an iron beryllide. There are three iron beryllides: -phase (hexagonal), -phase (FeBe5, Laves-MgCu2, a = 5.86 Å to 5.88 Å), and the -phase FeBe2 (Laves phase, hexagonal). At elevated temperatures, the FeBe5
ISSN:0010-9312
1938-159X
DOI:10.5006/1.3277574