scholarly journals A simple model of a glow discharge electron beam for materials processing

1997 ◽  
Vol 25 (3) ◽  
pp. 427-432 ◽  
Author(s):  
J.I. Etcheverry ◽  
N. Mingolo ◽  
J.J. Rocca ◽  
O.E. Martinez
2003 ◽  
Vol 777 ◽  
Author(s):  
J.S. Romero ◽  
A.G. Fitzgerald

AbstractCopper migration is observed in the SEM in amorphous GeSe2/Cu thin films when an electron beam is focused in pulsed or continuous operation on the surface of these thin films. The phenomenon can be explained using a simple model in which the population of D- centers is considered to increase upon electron irradiation. The increase in the D- center population is envisaged as due to the breaking of bonds by the electron radiation and by the constant presence of negative charge in irradiated regions. Changes in copper concentration of 20%-30% have been obtained. Additionally we have observed the local crystallization of amorphous GeSe2/Cu thin films in the TEM when the samples were subjected to intense electron bombardment. The crystalline product has been identified as Berzelianite (Cu2Se).


AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 1061-1064
Author(s):  
S. Larigaldie ◽  
D. Bize ◽  
A. K. Mohamed ◽  
M. Ory ◽  
J. Soutade ◽  
...  

2004 ◽  
Vol 186 (1-2) ◽  
pp. 40-46 ◽  
Author(s):  
S.G Walton ◽  
C Muratore ◽  
D Leonhardt ◽  
R.F Fernsler ◽  
D.D Blackwell ◽  
...  

1987 ◽  
Vol 51 (6) ◽  
pp. 409-411 ◽  
Author(s):  
S. A. Lee ◽  
L.‐U. A. Andersen ◽  
J. J. Rocca ◽  
M. Marconi ◽  
N. D. Reesor

Author(s):  
Igor Melnyk ◽  
Sergey Tugay ◽  
Volodymyr Kyryk ◽  
Iryna Shved

The algorithm is considered for calculating the focal distance of a hollow conical electron beam generated by high-voltage glow discharge electron guns with magnetic focusing of the beam in the drift region, as well as a method for calculating the diameter of the focal ring and its thickness for such a beam. The proposed algorithm is based on the theory of electron drift in the field of a focusing magnetic lens and is designed using the methods of discrete mathematics and the minimax analysis. The obtained simulation results made it possible to establish the influence of the magnetic lens current on the focal diameter of a hollow conical electron beam and on its focal ring thickness. It is shown that the change in the focal parameters of a hollow conical electron beam can be effectively provided through the regulation of the magnetic lens current.


2008 ◽  
pp. 155-230 ◽  
Author(s):  
H. Bluhm ◽  
B. Han ◽  
A. G. Chmielewski ◽  
D. von Dobeneck ◽  
U. Gohs ◽  
...  

2014 ◽  
Author(s):  
Seshadev Sahoo ◽  
Kevin Chou

Powder-bed electron beam additive manufacturing (EBAM) is a relatively new technology to produce metallic parts in a layer by layer fashion by melting and fusing metallic powders. EBAM is a rapid solidification process and the properties of the parts depend on the solidification behavior as well as the microstructure of the build material. Thus, the prediction of part microstructures during the process may be an important factor for process optimization. Nowadays, the increase in computational power allows for direct simulations of microstructures during materials processing for specific manufacturing conditions. Among different methods, phase-field modeling (PFM) has recently emerged as a powerful computational technique for simulating microstructure evolutions at the mesoscale during a rapid solidification process. PFM describes microstructures using a set of conserved and non-conserved field variables and the evolution of the field variables are governed by Cahn-Hilliard and Allen-Cahn equations. By using the thermodynamics and kinetic parameters as input parameters in the model, PFM is able to simulate the evolution of complex microstructures during materials processing. The objective of this study is to achieve a thorough review of PFM techniques used in various processes, attempted for an application to microstructure evolutions during EBAM. The concept of diffuse interfaces, phase field variables, thermodynamic driving forces for microstructure evolutions and the kinetic phase-field equations are described in this paper.


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