Solute Effects on Grain Boundary Electromigration and Diffusion

1972 ◽  
pp. 339-370 ◽  
Author(s):  
F. M. d’Heurle ◽  
A. Gangulee
Keyword(s):  
Grain Boundary ◽  
And Diffusion

scholarly journals Microstructure and Magnetic Properties of NdFeB Sintered Magnets Diffusion-Treated with Cu/Al Mixed Dyco Alloy-Powder

2017 ◽  
Vol 62 (2) ◽  
pp. 1263-1266 ◽  
Author(s):  
M.-W. Lee ◽  
K.-H. Bae ◽  
S.-R. Lee ◽  
H.-J. Kim ◽  
T.-S. Jang
Keyword(s):  
Grain Boundary ◽  
Diffusion Path ◽  
Boundary Phase ◽  
Core Shell ◽  
Phase Layer ◽  
Sintered Magnets ◽  
The Core ◽  
Shell Type ◽  
Property Changes ◽  
And Diffusion

AbstractWe investigated the microstructural and magnetic property changes of DyCo, Cu + DyCo, and Al + DyCo diffusion-treated NdFeB sintered magnets. The coercivity of all diffusion treated magnet was increased at 880ºC of 1stpost annealing(PA), by 6.1 kOe in Cu and 7.0 kOe in Al mixed DyCo coated magnets, whereas this increment was found to be relatively low (3.9 kOe) in the magnet coated with DyCo only. The diffusivity and diffusion depth of Dy were increased in those magnets which were treated with Cu or Al mixed DyCo, mainly due to comparatively easy diffusion path provided by Cu and Al because of their solubility with Ndrich grain boundary phase. The formation of Cu/Al-rich grain boundary phase might have enhanced the diffusivity of Dy-atoms. Moreover, relatively a large number of Dy atoms reached into the magnet and mostly segregated at the interface of Nd2Fe14B and grain boundary phases covering Nd2Fe14B grains so that the core-shell type structures were developed. The formation of highly anisotropic (Nd, Dy)2Fe14B phase layer, which acted as the shell in the core-shell type structure so as to prevent the reverse domain movement, was the cause of enhancing the coercivity of diffusion treated NdFeB magnets. Segregation of cobalt in Nd-rich TJP followed by the formation of Co-rich phase was beneficial for the coercivity enhancement, resulting in the stabilization of the metastable c-Nd2O3phase.

Investigating behaviours of hydrogen in a tungsten grain boundary by first principles: from dissolution and diffusion to a trapping mechanism

2010 ◽  
Vol 50 (2) ◽  
pp. 025016 ◽  
Author(s):  
Hong-Bo Zhou ◽  
Yue-Lin Liu ◽  
Shuo Jin ◽  
Ying Zhang ◽  
G.-N. Luo ◽  
...  
Keyword(s):  
Grain Boundary ◽  
First Principles ◽  
Trapping Mechanism ◽  
And Diffusion

Grain boundary random walks and diffusion in polycrystals

1993 ◽  
Vol 193 (2) ◽  
pp. 259-303 ◽  
Author(s):  
I.A. Lubashevskii ◽  
V.L. Alatortsev ◽  
A.G. Keijan
Keyword(s):  
Grain Boundary ◽  
Random Walks ◽  
And Diffusion

Grain boundary segregation and diffusion in Ag-S solid solution

1979 ◽  
Vol 27 (12) ◽  
pp. 1849-1854 ◽  
Author(s):  
B. Aufray ◽  
F. Cabane-Brouty ◽  
J. Cabane
Keyword(s):  
Solid Solution ◽  
Grain Boundary ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
And Diffusion

On the Adhesion of LPCVD WSi2 to Doped and Undoped Polysilicon

1988 ◽  
Vol 119 ◽  
Author(s):  
K. Shenai ◽  
P. A. Piacente ◽  
N. Lewis ◽  
M. D. McConnell ◽  
G. A. Smith ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Chemical Vapor ◽  
Atomic Ratio ◽  
Silicide Film ◽  
Grain Structures ◽  
Integrated Devices ◽  
Chemical Vapor Deposited ◽  
Electrical Conductivities ◽  
Pressure Chemical ◽  
And Diffusion

AbstractWe report on the adhesion characteristics of Low Pressure Chemical Vapor Deposited (LPCVD) WSi2 to doped and undoped polysilicon when used for fabricating silicon discreie and integrated devices. About 3000Å of silicon rich (Si:W atomic ratio of 2.6) LPCVD WSi2 was deposited on 6 kÅ of polysilicon and annealed in nitriding and oxidizing ambients at various temperatures from 1000°C to 1100°C to lower the sheet resistance. Detailed material analyses of as-deposited and annealed polycides were performed using Auger, SIMS, RBS, TEM, and SEM and electrical conductivities of the films were measured using the four point probe. In some samples, the oxide grown on the silicide film was wet etched prior to implanting and diffusing As corresponding to the source/drain diffusions in power FET's. It was observed that polysilicon doping, WSi2 deposition and annealing, oxide or nitride etching, implantation and diffusion of As - all had significant impact on the grain structures of silicide and polysilicon, adhesion of the silicide film to polysilicon, and the electrical conductivity of the silicide. In samples where the oxide grown on the silicide was wet etched, enhanced grain boundary related oxidation of the silicide and polysilicon and seepage of the wet etchant through sequential etching of grain boundary oxide resulted in poor adhesion of WSi2 grains to polysilicon and eventual silicide peeloff. This problem was severe in samples which were not implanted with As but subjected to 900°C, 60 min. source drive.

Constrained Grain Boundary Diffusion In Thin Copper Films

2004 ◽  
Vol 821 ◽  
Author(s):  
Markus J. Buehler ◽  
Alexander Hartmaier ◽  
Huajian Gao
Keyword(s):  
Thin Films ◽  
Theoretical Analysis ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Atomic Scale ◽  
Diffusional Creep ◽  
Copper Films ◽  
And Diffusion

AbstractIn a recent study of diffusional creep in polycrystalline thin films deposited on substrates, we have discovered a new class of defects called the grain boundary diffusion wedges (Gao et al., Acta Mat. 47, pp. 2865-2878, 1999). These diffusion wedges are formed by stress driven mass transport between the free surface of the film and the grain boundaries during the process of substrate-constrained grain boundary diffusion. The mathematical modeling involves solution of integro-differential equations representing a strong coupling between elasticity and diffusion. The solution can be decomposed into diffusional eigenmodes reminiscent of crack-like opening displacement along the grain boundary which leads to a singular stress field at the root of the grain boundary. We find that the theoretical analysis successfully explains the difference between the mechanical behaviors of passivated and unpassivated copper films during thermal cycling on a silicon substrate. An important implication of our theoretical analysis is that dislocations with Burgers vector parallel to the interface can be nucleated at the root of the grain boundary. This is a new dislocation mechanism in thin films which contrasts to the well known Mathews-Freund-Nix mechanism of threading dislocation propagation. Recent TEM experiments at the Max Planck Institute for Metals Research have shown that, while threading dislocations dominate in passivated metal films, parallel glide dislocations begin to dominate in unpassivated copper films with thickness below 400 nm. This is consistent with our theoretical predictions. We have developed large scale molecular dynamics simulations of grain boundary diffusion wedges to clarify the nucleation mechanisms of parallel glide in thin films. Such atomic scale simulations of thin film diffusion not only show results which are consistent with both continuum theoretical and experimental studies, but also revealed the atomic processes of dislocation nucleation, climb, glide and storage in grain boundaries. The study should have far reaching implications for modeling deformation and diffusion in micro- and nanostructured materials.

Grain boundary cosegregation and diffusion in Cu(Fe,S) solid solution

1983 ◽  
Vol 31 (7) ◽  
pp. 1047-1052 ◽  
Author(s):  
A. Pineau ◽  
B. Aufray ◽  
F. Cabane-Brouty ◽  
J. Cabane
Keyword(s):  
Solid Solution ◽  
Grain Boundary ◽  
And Diffusion

A dynamical model of a crystal structure - IV. Grain boundaries

1952 ◽  
Vol 212 (1111) ◽  
pp. 576-584 ◽  
Keyword(s):  
Crystal Structure ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Large Angle ◽  
Gradual Transition ◽  
Small Angle Boundary ◽  
Pure Metals ◽  
And Diffusion ◽  
Large Angle Boundary ◽  
Dislocation Walls

Four photographs of bubble rafts are used as a basis for discussion of the structure of grain boundaries in pure metals. In these photographs one can follow the gradual transition from a small-angle boundary made up of clearly separate dislocations to a large-angle boundary where the dislocation structure is hardly recognizable. As the angle is increased, a continuous shortening of the dislocations, accompanied by the widening of a crack on the tensile side, is seen, and the process culminates in a structure which is perhaps best described in terms of local fit and misfit. The fact is also illustrated that the dislocation content of the boundary depends on the angle of the boundary, as well as on the disorientation of the crystals that it separates. If a boundary turns it must therefore gain or lose dislocations. The bearing of this on the measurement of grain-boundary energies is discussed. Other points considered concern the range of validity of calculations of the energy of dislocation walls, and slip and diffusion along grain boundaries.

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