Zero Creep Measurements of the Interfacial Free Energy of Ag/Ni Multilayers

1991 ◽  
Vol 239 ◽  
Author(s):  
D. Josell ◽  
F. Spaepen
Keyword(s):  
Thin Films ◽  
Free Energy ◽  
Grain Boundary ◽  
Interfacial Free Energy ◽  
Specific Model ◽  
Diffusional Creep ◽  
Multilayer Thin Films ◽  
Creep Tests ◽  
Creep Measurements ◽  
Microstructural Data

ABSTRACTThe free energy γAgNi associated with an interface between layers of silver and nickel has been experimentally determined. Creep tests were conducted on multilayer thin films to determine the load at which the length of the film neither shrank nor stretched. The interfacial free energy was obtained from this zero creep load and microstructural data using a specific model for the grain boundary diffusional creep in multilayers.

Determining Interfacial Free Energies from Creep Experiments on Silver-Iron Multilayers

1994 ◽  
Vol 356 ◽  
Author(s):  
D. Josell ◽  
Z.L. Wang
Keyword(s):  
Thin Films ◽  
Free Energy ◽  
Boundary Diffusion ◽  
Interfacial Free Energy ◽  
Multilayer Thin Films ◽  
Free Energies ◽  
Diffusion Controlled ◽  
Interfacial Free Energies ◽  
Over Time ◽  
Microstructural Data

AbstractExperiments were conducted on multilayer thin films to determine the free energies associated with silver/iron interfaces. Creep studies determined the loads for which the multilayers neither shrank nor stretched over time. Microstructural data was used with the zero creep loads in a model for grain boundary diffusion controlled creep in multilayers to determine the interfacial free energy.

Atomistic and Continuum Studies of Diffusional Creep and Associated Dislocation Mechanisms in thin Films on Substrates

2003 ◽  
Vol 779 ◽  
Author(s):  
Markus J. Buehler ◽  
Alexander Hartmaier ◽  
Huajian Gao
Keyword(s):  
Thin Films ◽  
Stress Field ◽  
Grain Boundary ◽  
Large Scale ◽  
Strain Relaxation ◽  
Dislocation Dynamics ◽  
Biaxial Stress ◽  
Diffusional Creep ◽  
Material Transport ◽  
Dynamics Simulations

AbstractMotivated by recent theoretical and experimental progress, large-scale atomistic simulations are performed to study plastic deformation in sub-micron thin films. The studies reveal that stresses are relaxed by material transport from the surface into the grain boundary. This leads to the formation of a novel defect identified as diffusion wedge. Eventually, a crack-like stress field develops because the tractions along the grain boundary relax, but the adhesion of the film to the substrate prohibits strain relaxation close to the interface. This causes nucleation of unexpected parallel glide dislocations at the grain boundary-substrate interface, for which no driving force exists in the overall biaxial stress field. The observation of parallel glide dislocations in molecular dynamics studies closes the theory-experiment-simulation linkage. In this study, we also compare the nucleation of dislocations from a diffusion wedge with nucleation from a crack. Further, we present preliminary results of modeling constrained diffusional creep using discrete dislocation dynamics simulations.

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.

Thermal Grooving in Single versus Multilayer Thin Films

2004 ◽  
Vol 854 ◽  
Author(s):  
Peter M. Anderson ◽  
Jue Wang ◽  
Sridhar Narayanaswamy
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Boundary ◽  
Multilayer Thin Films ◽  
Multilayer Thin Film ◽  
Penetration Distance ◽  
Grain Boundary Grooves ◽  
Single Versus

ABSTRACTA 2D analytic result is presented for the penetration distance P of grain boundary grooves as a function of time t during heating and straining of polycrystalline multilayer thin films with immiscible phases. These grooves can ultimately pinch off individual layers. The result shows that P ∼ t0.25 initially and P ∼ t at longer time. This new analysis contrasts single- versus multilayer thin film response.

Effect of Microstructure on Phase Formation in Reaction of The Nb/Al Multilayer Thin Films

1991 ◽  
Vol 230 ◽  
Author(s):  
Katayun Barmak ◽  
Kevin R. Coffey ◽  
David A. Rudman ◽  
Simon Foner
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Diagram ◽  
Grain Boundary ◽  
Phase Formation ◽  
Boundary Diffusion ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Thin Layers ◽  
Multilayer Thin Films

AbstractWe investigated the phase formation sequence in the reaction of multilayer thin films of Nb/Al with overall compositions of 25 and 33 at.% AI. We report novel phenomena which distinguish thin-film reactions unequivocally from those in bulk systems. For sufficiently thin layers composition and stability of product phases are found to deviate significantly from that predicted from the equilibrium phase diagram. We demonstrate that in the Nb/Al system the length scales below which such deviations occur is about 150 nm. We believe that these phenomena occur due to the importance of grain boundary diffusion and hence microstructure in these thin films.

Measurement and Comparison of Relative Interfacial Energy Ratios in Ni and A Ni-Cr Alloy

1970 ◽  
Vol 28 ◽  
pp. 434-435
Author(s):  
W.N. Lin ◽  
L.E. Murr
Keyword(s):  
Thin Films ◽  
Free Energy ◽  
Grain Boundary ◽  
Interfacial Energy ◽  
Chromium Alloy ◽  
Nickel Chromium ◽  
Thin Foils ◽  
Energy Ratios ◽  
Cold Rolled ◽  
Diffraction Microscopy

Initially cold-rolled and annealed (15 min. at 1060°C) sheet specimens of 0.004 in. thick nickel (99. 86%) and 0.005 in. thick nickel-chromium alloy (78% Ni, 20% Cr, 0.3%Mn, 1.7% Si) were electropolished to a thickness of 1000-3000 Å in a solution containing 240cm3 H2O, 340 cm3 H2SO4 and 420 cm3H3PO4. Coherent twin-grain boundary inter sections in these Ni and Ni-Cr alloy thin films were examined by transmission and diffraction microscopy. Figs. 1 and 2 illustrate the typical twin-grain boundary intersecting systems observed in Ni and Ni-Cr alloy thin foils respectively. The ratios of twin boundary free energy to grain boundary free energy, γtb/γgb, were measured by using the techniques outlined by Murr and Murr, et al.

Effect of interfacial free energy on hydriding reaction of Mg–Ni thin films

2007 ◽  
Vol 90 (2) ◽  
pp. 021917 ◽  
Author(s):  
L. Z. Ouyang ◽  
S. Y. Ye ◽  
H. W. Dong ◽  
M. Zhu
Keyword(s):  
Thin Films ◽  
Free Energy ◽  
Interfacial Free Energy ◽  
Hydriding Reaction
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