Production and Metallographic Examination of Precipitable Cu–Mg Alloys

A. Zilly; U. Christian; S. Kött; D. Nobiling; N. Jost

doi:10.3139/147.110135

Rare Earth Metal-Based Intermetallics Formation in Al–Cu–Mg and Al–Si–Cu–Mg Alloys: A Metallographic Study

Advances in Materials Science and Engineering ◽

10.1155/2018/7607465 ◽

2018 ◽

Vol 2018 ◽

pp. 1-15 ◽

Cited By ~ 3

Author(s):

A. M. Samuel ◽

E. M. Elgallad ◽

M. G. Mahmoud ◽

H. W. Doty ◽

S. Valtierra ◽

...

Keyword(s):

Eutectic Reaction ◽

Earth Metal ◽

Nucleation Site ◽

Mg Alloys ◽

Significant Drop ◽

Metallographic Examination ◽

Gray Phase ◽

White Phase ◽

Eutectic Si ◽

Fixed Composition

This study was conducted on Al–Cu–Mg and Al–Si–Cu–Mg alloys containing either 5%La or 5%Ce. Two levels of Ti addition were examined, i.e., 0.05% and 0.15%. Thermal analysis was the only technique used to obtain castings, from which samples were then sectioned for metallographic examination. Based on the results obtained, the following points may be highlighted. Addition of a fairly large amount of RE metals (La or Ce) leads to the appearance of several peaks in the solidification curve between the precipitation of the primary α-Al phase and the (Al–Al2Cu) eutectic reaction. Although a significant drop in the eutectic temperature is caused by the addition of 5%La or Ce, the corresponding modification of the eutectic Si is marginal. Two main types of intermetallics were documented: a gray phase in the form of sludge with a fixed composition and a white phase in the shape of thin platelets. Due to the high affinity of RE to react with Si, Fe, and Cu, several compositions were obtained explaining the observed multiple peaks in the solidification curve. Judging by the morphology of the gray phase, it is assumed that this phase is precipitated in the liquid state and acts as a nucleation site for the white phase. Lanthanum and Ce can substitute each other.

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Microstructure of Electro-Eroded Cemented Carbide Surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101165 ◽

1968 ◽

Vol 26 ◽

pp. 284-285

Author(s):

V. N. Filimonenko ◽

M. H. Richman ◽

J. Gurland

Keyword(s):

Surface Layer ◽

Cobalt Content ◽

Cemented Carbides ◽

Face Centered Cubic ◽

X Ray Diffraction ◽

Metallographic Examination ◽

Standard Procedures ◽

Face Centered ◽

Diamond Paste ◽

Plastic Carbon

The high temperatures and pressures that are found in a spark gap during electrical discharging lead to a sharp phase transition and structural transformation in the surface layer of cemented carbides containing WC and cobalt. By means of X-ray diffraction both W2C and a high-temperature monocarbide of tungsten (face-centered cubic) were detected after electro-erosion. The W2C forms as a result of the peritectic reaction, WC → W2C+C. The existence and amount of the phases depend on both the energy of the electro-spark discharge and the cobalt content. In the case of a low-energy discharge (i.e. C=0.01μF, V = 300v), WC(f.c.c.) is generally formed in the surface layer. However, at high energies, (e.g. C=30μF, V = 300v), W2C is formed at the surface in preference to the monocarbide. The phase transformations in the surface layer are retarded by the presence of larger percentages of cobalt.Metallographic examination of the electro-eroded surfaces of cemented carbides was carried out on samples with 5-30% cobalt content. The specimens were first metallographically polished using diamond paste and standard procedures and then subjected to various electrical discharges on a Servomet spark machining device. The samples were then repolished and etched in a 3% NH4OH electrolyte at -0.5 amp/cm2. Two stage plastic-carbon replicas were then made and shadowed with chromium at 27°.

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Electron-Probe Quantitative Energy-Dispersive Analysis of Trace Magnesium Concentrations in Ag-Mg Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010016501x ◽

1996 ◽

Vol 54 ◽

pp. 510-511

Author(s):

R. B. Marinenko

Keyword(s):

Electron Probe ◽

Energy Dispersive Spectrometry ◽

Mg Alloys ◽

Energy Dispersive ◽

Energy Dispersive Analysis ◽

High Tc ◽

Alloy Wire ◽

High Tc Superconductor ◽

Eds Analysis ◽

Superior Mechanical Properties

Internally oxidized Ag-Mg alloys are used as sheaths for high Tc superconductor wires because of their superior mechanical properties. The preparation and characteristics of these materials have been reported. Performance of the sheaths depends on the concentration of the magnesium which generally is less than 0.5 wt. percent. The purpose of this work was to determine whether electron probe microanalysis using energy dispersive spectrometry (EDS) could be used to quantitate three different Ag-Mg alloys. Quantitative EDS analysis can be difficult because the AgL escape peak occurs at the same energy (1.25 keV) as the Mg Kα peak. An EDS spectrum of a Ag-Mg alloy wire is compared to a pure Ag spectrum in Fig. 1.

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