scholarly journals Interdiffusion and Grain-Boundary Migration in Au/Cu Bilayers During Ion-Irradiation

1991 ◽  
Vol 235 ◽  
Author(s):  
Dale E. Alexander ◽  
L. E. Rehn ◽  
Peter M. Baldo
Keyword(s):  
Grain Boundary ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Irradiation ◽  
Boundary Migration ◽  
Ion Beam ◽  
Film Surface ◽  
Grain Boundary Migration ◽  
Bilayer Films ◽  
Small Probe ◽  
Annealing Experiments

ABSTRACTIon irradiation and annealing experiments have been conducted on Au/Cu bilayer films to evaluate the effect of irradiation on diffusion-induced grain boundary migration (DIGM). The Au films were prepared with a large-grained microstructure with grain boundaries perpendicular to the film surface and extending through the film thickness. Irradiations were conducted with 1.5 MeV Kr at 228°C. Rutherford backscattering spectrometry of the samples revealed that interdiffusion was substantially enhanced in the irradiated area relative to the unirradiated area. Both irradiated and annealed-only areas were characterized by a nearly uniform composition of 14 at.% and 7 at.% Cu respectively through the entire thickness of the underlying Au film. Small probe X-ray energy dispersive spectroscopy showed significant lateral compositional homogeneities in both irradiated and annealed areas. These two results are consistent with previous observations of DIGM in the Au/Cu system, suggesting that this previously unexamined interdiffusion mechanism contributes to ion beam mixing.

scholarly journals The Effect of Digm and Irradiation-Induced Grain Growth on Interdiffusion in Bilayer Ion-Beam Mixing Experiments

1992 ◽  
Vol 279 ◽  
Author(s):  
Dale E. Alexander ◽  
L. E. Rehn ◽  
Peter M. Baldo ◽  
Y. Gao
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Grain Growth ◽  
Treatment Time ◽  
Ion Irradiation ◽  
Boundary Migration ◽  
Ion Beam ◽  
Grain Boundary Migration ◽  
Ion Beam Mixing ◽  
Boundary Velocity

ABSTRACTExperiments were performed demonstrating that ion irradiation enhances diffusion-induced grain boundary migration (DIGM) in polycrystalline Au/Cu bilayers. Here, a model is presented relating film-averaged Cu composition in Au with treatment time, grain size and film thickness. Application of this model to the experimental results indicates that irradiation enhances DIGM by increasing the grain boundary velocity. The effects of DIGM and irradiation-induced grain growth on the temperature dependence of ion mixing in bilayers are discussed.

Ion-beam mixing of Ni/Pd layers: II. Thermally assisted regime (>500K)

1988 ◽  
Vol 3 (6) ◽  
pp. 1063-1071 ◽  
Author(s):  
U. G. Akano ◽  
D. A. Thompson ◽  
W. W. Smeltzer ◽  
J. A. Davies
Keyword(s):  
Grain Boundary ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Effective Diffusivity ◽  
Bilayer Films ◽  
Diffusion Analysis ◽  
The Mean ◽  
Atomic Mixing ◽  
Lattice Diffusivity

Atomic mixing in Ni/Pd bilayer films due to 120 keV Ar+ irradiation in the thermally assisted regime (523−673 K) has been measured, in situ, using Rutherford backscattering with 2.0 MeV 4He+ ions. The mean diameter of grains in these polycrystallinc films increased from 10 to 60 nm, following Ar+ bombardment at 573 K. Initial mixing was rapid due to grain boundary diffusion and incorporation of the metal solute into the solvent metal matrix by grain growth; this mixing stage was essentially complete within 10 min for annealed films or after an Ar+ dose of 4 × 1015 cm−2 in irradiated films (10 min irradiation). No further measurable mixing occurred in the annealed, unirradiated films. For the irradiated samples the initial rapid mixing (6−35 atoms/ion) was followed by a slower mixing stage of 0.7–1.8 atoms/ion for irradiation doses of up to 2.5 × 1016 Ar+ cm−2. The Ar+ bombardment gave rise to much smaller mixing levels when the Pd films were deposited on large-grain or single-crystal Ni. A diffusion analysis demonstrates that the effective diffusivity, Deff, for ion-irradiation-enhanced mixing in the thermally assisted regime satisfied the relation Dl < Deff < DB, where the ratio of the grain boundary to lattice diffusivity was DB/Dl > 106.

scholarly journals Evidence of Stress Development as a Source of Driving Force for Grain-Boundary Migration in a Ni Bicrystalline TEM Specimen

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 360
Author(s):  
Sung Bo Lee ◽  
Jinwook Jung ◽  
Heung Nam Han
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundary ◽  
Focused Ion Beam ◽  
Boundary Migration ◽  
Ion Beam ◽  
Grain Boundary Migration ◽  
Migration Behavior ◽  
Stress Development ◽  
Transmission Electron

In a previous study, using high-resolution transmission electron microscopy (HRTEM), we examined grain-boundary migration behavior in a Ni bicrystal. A specimen for transmission electron microscopy (TEM) was prepared using focused ion beam. The Ni lamella in the specimen was composed of two grains with surface normal directions of [1 0 0] and [1 1 0]. As the lamella was heated to 600 °C in a TEM, it was subjected to compressive stresses. The stress state of the Ni lamella approximated to the isostress condition, which was confirmed by a finite element method. However, the stress development was not experimentally confirmed in the previous study. In the present study, we present an observation of stacking faults with a length of 40–70 nm at the grain boundary as direct evidence of the stress development.

Enhancement of diffusion‐induced grain boundary migration by ion irradiation

1993 ◽  
Vol 62 (14) ◽  
pp. 1597-1599 ◽  
Author(s):  
Dale E. Alexander ◽  
L. E. Rehn ◽  
P. M. Baldo ◽  
Y. Gao
Keyword(s):  
Grain Boundary ◽  
Ion Irradiation ◽  
Boundary Migration ◽  
Grain Boundary Migration

scholarly journals Cross-Sectional TEM Studies of DIGM in Irradiated Au-Cu Bilayers

1992 ◽  
Vol 279 ◽  
Author(s):  
Yuzun Gao ◽  
Dale E. Alexander ◽  
L. E. Rehn
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundary ◽  
Energy Dispersive Spectroscopy ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Cross Sectional ◽  
X Ray ◽  
Small Probe ◽  
Transmission Electron

ABSTRACTCross-sectional transmission electron microscopy was used to study diffusion-induced grain boundary migration (DIGM) in irradiated and annealed Au/Cu bilayers. Using this technique, in combination with small probe X-ray energy dispersive spectroscopy, DIGM alloyed zones in Au were identified in an irradiated sample.

Measurement of solute segregation to grain boundaries in the AEM: A review

1988 ◽  
Vol 46 ◽  
pp. 606-607
Author(s):  
D. B. Williams ◽  
A. D. Romig
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Boundary Misorientation ◽  
Collector Plate ◽  
Segregation Process ◽  
Grain Boundary Misorientation ◽  
Structure Boundary ◽  
Equilibrium Segregation

The segregation of solute or imparity elements to grain boundaries can occur by three well-defined processes. The first is Gibbsian segregation in which an element of minimal matrix solubility confines itself to a monolayer at the grain boundary. Classical examples include Bi in Cu and S or P in Fe. The second process involves the depletion of excess matrix solute by volume diffusion to the boundary. In the boundary, the solute atoms diffuse rapidly to precipitates, causing them to grow by the ‘collector-plate mechanism.’ Such grain boundary diffusion is thought to initiate “Diffusion-Induced Grain Boundary Migration,” (DIGM). This process has been proposed as the origin of eutectoid transformations or discontinuous grain boundary reactions. The third segregation process is non-equilibrium segregation which result in a solute build-up around the boundary because of solute-vacancy interactions.All of these segregation phenomena usually occur on a sub-micron scale and are often affected by the nature of the grain boundary (misorientation, defect structure, boundary plane).

Domain coarsening by grain boundary migration in ordered Ni4Mo

1986 ◽  
Vol 44 ◽  
pp. 560-561
Author(s):  
K. Vasudevan ◽  
H. P. Kao ◽  
C. R. Brooks ◽  
E. E. Stansbury
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Short Range ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Rapid Cooling ◽  
Temperature Range ◽  
Fee Structure ◽  
Domain Coarsening ◽  
Boundary Reaction

The Ni4Mo alloy has a short-range ordered fee structure (α) above 868°C, but transforms below this temperature to an ordered bet structure (β) by rearrangement of atoms on the fee lattice. The disordered α, retained by rapid cooling, can be ordered by appropriate aging below 868°C. Initially, very fine β domains in six different but crystallographically related variants form and grow in size on further aging. However, in the temperature range 600-775°C, a coarsening reaction begins at the former α grain boundaries and the alloy also coarsens by this mechanism. The purpose of this paper is to report on TEM observations showing the characteristics of this grain boundary reaction.

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