Origin of the Hyperfine Fields in Pure Fe and at Solute Atoms in Fe

1971 ◽  
Vol 4 (11) ◽  
pp. 4081-4091 ◽  
Author(s):  
Mary Beth Stearns
Keyword(s):  
Hyperfine Fields ◽  
Solute Atoms

Solute redistribution during in-situ irradiation of alloys in the high voltage electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 370-371
Author(s):  
P. R. Okamoto ◽  
N.Q. Lam ◽  
R. L. Lyles
Keyword(s):  
Electron Microscope ◽  
High Voltage ◽  
Driving Forces ◽  
Solute Diffusion ◽  
Solute Redistribution ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Thin Foils ◽  
Solute Atoms

During irradiation of thin foils in a high voltage electron microscope (HVEM) defect gradients will be set up between the foil surfaces and interior. In alloys defect gradients provide additional driving forces for solute diffusion since any preferential binding and/or exchange between solute atoms and mobile defects will couple a net flux of solute atoms to the defect fluxes. Thus, during irradiation large nonequilibrium compositional gradients can be produced near the foil surfaces in initially homogeneous alloys. A system of coupled reaction-rate and diffusion equations describing the build up of mobile defects and solute redistribution in thin foils and in a semi-infinite medium under charged-particle irradiation has been formulated. Spatially uniform and nonuniform damage production rates have been used to model solute segregation under electron and ion irradiation conditions.An example calculation showing the time evolution of the solute concentration in a 2000 Å thick foil during electron irradiation is shown in Fig. 1.

Application of analytical electron microscopy to studies of equilibrium and non-equilibrium segregation in materials

1992 ◽  
Vol 50 (2) ◽  
pp. 1214-1215
Author(s):  
Edward A Kenik
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Extended Defects ◽  
Probe Diameter ◽  
Specimen Holder ◽  
Analytical Electron ◽  
Scanning Transmission ◽  
Solute Atoms ◽  
Equilibrium Segregation ◽  
Non Equilibrium

Segregation of solute atoms to grain boundaries, dislocations, and other extended defects can occur under thermal equilibrium or non-equilibrium conditions, such as quenching, irradiation, or precipitation. Generally, equilibrium segregation is narrow (near monolayer coverage at planar defects), whereas non-equilibrium segregation exhibits profiles of larger spatial extent, associated with diffusion of point defects or solute atoms. Analytical electron microscopy provides tools both to measure the segregation and to characterize the defect at which the segregation occurs. This is especially true of instruments that can achieve fine (<2 nm width), high current probes and as such, provide high spatial resolution analysis and characterization capability. Analysis was performed in a Philips EM400T/FEG operated in the scanning transmission mode with a probe diameter of <2 nm (FWTM). The instrument is equipped with EDAX 9100/70 energy dispersive X-ray spectrometry (EDXS) and Gatan 666 parallel detection electron energy loss spectrometry (PEELS) systems. A double-tilt, liquid-nitrogen-cooled specimen holder was employed for microanalysis in order to minimize contamination under the focussed spot.

MAGNETIC HYPERFINE FIELDS AT 61Ni NUCLEI IN Ni-Pd ALLOYS

1971 ◽  
Vol 32 (C1) ◽  
pp. C1-783-C1-784 ◽  
Author(s):  
F. E. OBENSHAIN ◽  
W. A. GLAESER ◽  
G. CZJZEK ◽  
J. E. TANSIL
Keyword(s):  
Magnetic Hyperfine ◽  
Hyperfine Fields
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