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.

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.

Quantitative Evaluation of the Interfacial Free Energies at A Solid-Liquid Lamellar Eutectic Interface

1981 ◽  
Vol 12 ◽  
Author(s):  
W. F. Kaukler ◽  
J. W. Rutter
Keyword(s):  
Free Energy ◽  
Solid Phase ◽  
Interfacial Free Energy ◽  
Eutectic System ◽  
Liquid Interfaces ◽  
Free Energies ◽  
Two Phases ◽  
Interfacial Free Energies ◽  
The Individual ◽  
Solid Liquid

The solid-liquid interfacial free energies of each of the individual phases comprising the eutectic system, Carbon Tetrabromide-Hexachloroethane, were measured as a function of composition using a “grain boundary groove” technique. Thermodynamic data were combined with groove shape measurements made from high resolution optical photomicrographs of the solid-liquid interfaces to give the interfacial free energy data. An interfacial free energy balance at the eutectic trijunction was performed to obtain all the forces acting on that point. The three interphase interfacial free energies at the eutectic trijunctions as well as a solid-solid phase boundary torque were evaluated.It was found that the solid-liquid interfacial free energies of the two phases of the eutectic could be evaluated from photomicrographs of growing or stationary eutectic interfaces. In addition, it was found that for a substantial range of freezing conditions the eutectic interface shape can be predicted from a knowledge of the interfacial free energies alone.

Interfacial Free Energies and the Creep of Multilayer Thin Films

1997 ◽  
Vol 505 ◽  
Author(s):  
D. Josell ◽  
W. C. Carter
Keyword(s):  
Thin Films ◽  
New Technique ◽  
Multilayer Thin Films ◽  
Free Energies ◽  
Creep Properties ◽  
Multilayer Foils ◽  
A New Technique ◽  
Interfacial Free Energies

ABSTRACTExperiments utilizing the creep properties of multilayer thin films to determine interfacial free energies are presented with essential theory. A new technique utilizing tubular multilayer foils is then described.

Effect of Modification by WTP-08 on Dispersity of Nanosized CalciumCarbonate and Its Mechanism

2011 ◽  
Vol 688 ◽  
pp. 51-56
Author(s):  
Hao Ding ◽  
Bai Kun Wang ◽  
Ning Liang ◽  
Kun Liu
Keyword(s):  
Free Energy ◽  
Calcium Carbonate ◽  
Surface Energy ◽  
Chemical Method ◽  
Interfacial Free Energy ◽  
Free Energies ◽  
Polar Medium ◽  
Polar Media ◽  
Thermodynamic Effect ◽  
Interfacial Free Energies

The dispersity of nanosized calcium carbonate modified by alkyl amine dimethyl phosphonic acid (WTP-08) through mechano-chemical method in different media was investigated. The modification mechanism was investigated by analyzing the surface energy and its thermodynamic effect on dispersity of nanosized calcium carbonate. The results show that the free energies of nanosized calcium carbonate modified by WTP-08 and its interfacial free energies in air and non-polar media decrease significantly, while the interfacial free energy in water increases remarkably. It can be concluded that modification by WTP-08 improves the dispersion tendency of nanosized calcium carbonate in air and non-polar medium, while it decreases in water. Therefore, modification by WTP-08 makes the dispersity of nanosized calcium carbonate increase in air and non-polar medium and decrease in water.

Modeling the Diffusion-Controlled Growth of Needle and Plate-Shaped Precipitates

2002 ◽  
Vol 731 ◽  
Author(s):  
Z. Guo ◽  
W. Sha
Keyword(s):  
Free Energy ◽  
Transformation Strain ◽  
Interfacial Free Energy ◽  
Growth Theory ◽  
Controlled Growth ◽  
Precipitate Morphology ◽  
Interface Kinetics ◽  
Diffusion Controlled ◽  
Precipitate Growth ◽  
Strain Stress

AbstractVarious theories have been developed to describe the diffusion-controlled growth of precipitates with shapes approximating needles or plates. The most comprehensive one is due to Ivantsov, Horvay and Cahn, and Trivedi (HIT theory), where all the factors that may influence the precipitate growth, i.e. diffusion, interface kinetics and capillarity, are accounted for within one equation. However, HIT theory was developed based on assumptions that transformation strain/stress and interfacial free energy are isotropic, which are not true in most of the real systems. An improved growth theory of precipitates of needle and plate shapes was developed in the present study. A new concept, the compression ratio, was introduced to account for influences from the anisotropy of transformation strain/stress and interfacial free energy on the precipitate morphology. Experimental evidence supports such compression effect. Precipitate growth kinetics were quantified using this concept. The improved HIT theory (IHIT theory) was then applied to study the growth of Widmanstatten austenite in ferrite in Fe-C-Mn steels. The calculated results agree well with the experimental observations.

Studies of Ag/Fe Interfacial Free Energies by Biaxial Zero Creep Experiments

2003 ◽  
Vol 10 (05) ◽  
pp. 763-769 ◽  
Author(s):  
Bing An ◽  
Tong-Jun Zhang ◽  
Chao Yuan ◽  
Kun Cui
Keyword(s):  
Rf Magnetron Sputtering ◽  
Film Stress ◽  
Multilayer Thin Films ◽  
Free Energies ◽  
Stress Monitoring ◽  
Isothermal Process ◽  
Long Duration ◽  
Grain Distribution ◽  
Interface Free Energy ◽  
Interfacial Free Energies

Biaxial zero creep experiments based on the Josell model were performed on Ag/Fe multilayer thin films to determine their interfacial free energies. Various multilayer samples on stiff wafers prepared by RF magnetron sputtering were subjected to annealing of long duration at 550°C, while a substrate curvature technique was employed for real-time film stress monitoring. Sufficient plastic flow in films makes possible a zero creep equilibrium state to present during this isothermal process, and as a result the interfacial free energies in multilayer interfaces are equilibrated with the elastic strain energies arising from the substrate bending. There is no collapse in the annealed multilayer structures. They are still stably layer-built and exhibit a column grain distribution. XRD results show that Ag and Fe layers have (111) and (110) preferred orientations, respectively. In accordance with a revised Josell model, the equilibrium stresses were measured and the Ag (111)/ Fe (110) interface free energy at 550°C was found to be 0.97 ± 0.13 J/m 2.

Nucleation & Growth of Precipitates in Transformations Driven by Diffusion

1997 ◽  
Vol 481 ◽  
Author(s):  
N. Clavaguera ◽  
M.T. Clavaguera-Mora
Keyword(s):  
Free Energy ◽  
Calculated Data ◽  
Energy Difference ◽  
Calphad Approach ◽  
Free Energies ◽  
Free Energy Difference ◽  
Diffusion Controlled ◽  
The Matrix ◽  
Rapidly Solidified ◽  
Selection Of

ABSTRACTA theoretical analysis of the transformation kinetics which accounts for nuclei, either prequenched or created homogeneously, and whose growth are controlled by diffusion is presented. The change in growth habit intervening during the transformation is analysed in terms of the evolution of the free energy difference between the precipitate and the matrix at the interface, ΔG1. In the Avrami formalism, this quantity accounts for the competition between interface and diffusion controlled growth whereas the nucleation events are driven by the free energy difference between the precipitate and the bulk matrix. Competition and selection of precipitate phases in highly undercooled melts using the CALPHAD approach for the evaluation of the free energies and the changes in diffusivity with concentration are analysed. Experimental vs. calculated data are discussed in some rapidly solidified metallic systems.

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.

Dissolution of A2Ti2O7 (A = Y3+, Gd3+, or Lu3+) Pyrochlore by Experiment at pH = 2, T = 90°C: Evidence for Solubility Control Using a Linear Free Energy Model

2002 ◽  
Vol 713 ◽  
Author(s):  
J. P. Icenhower ◽  
B. P. McGrail ◽  
W. J. Weber ◽  
B. D. Begg ◽  
N. J. Hess ◽  
...  
Keyword(s):  
Free Energy ◽  
Ligand Exchange ◽  
Energy Model ◽  
Free Energies ◽  
Exchange Reactions ◽  
Linear Free Energy ◽  
Diffusion Controlled ◽  
Rate Of Reaction ◽  
Dissolution Model ◽  
Free Energy Model

ABSTRACTWe performed a series of dissolution experiments with well-characterized pyrochlore ceramics with the formula A2Ti2O7, where A = Y3+, Gd3+, or Lu3+ in H2O- and D2Obased solutions [pH(D) = 2] at 90°C. Normalized log10 dissolution rates (g·m−2·d−1) in H2O-based solutions increase from Lu2Ti2O7 (−3.2 to –3.3) to Gd2Ti2O7 (−2.6 to –2.9), to Y2Ti2O7 (−1.9 to –2.0). Rates in D20-based solutions are indistinguishable from rates in H2O, indicating that release of elements is probably not diffusion controlled. A recent dissolution model, based on ligand-exchange reactions, suggests that the rate of reaction should increase in inverse order of the cation field strength: Lu < Y < Gd (where the cation denotes the appropriate pyrochlore composition), which is not observed. Evaluation of the thermodynamic stability of the three solids was performed using a linear free-energy model and reported free energies of formation. The calculations indicate that reactivity should follow in the progression Lu < Gd < Y, as observed in the dissolution experiments. Our data indicates, therefore, that dissolution models based on ligand-exchange reactions may not be strictly applicable to simple pyrochlore minerals.

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