Gibbs-Thompson Effect as Driving Force for Liquid Film Migration

2020 ◽  
Author(s):  
Marta Dias ◽  
Marcin Rosiński ◽  
Pedro.C.R. Rodrigues ◽  
José Brito Correia ◽  
Patricia Almeida Carvalho
Keyword(s):  
Liquid Film ◽  
Driving Force ◽  
Liquid Film Migration

scholarly journals Modelling of liquid film migration in Al-Cu alloys

2022 ◽  
Vol 380 (2217) ◽  
Author(s):  
Hui Fang ◽  
Stephanie Lippmann ◽  
Qingyu Zhang ◽  
Mingfang Zhu ◽  
Markus Rettenmayr
Keyword(s):  
Temperature Gradient ◽  
Liquid Film ◽  
Microstructural Evolution ◽  
Driving Force ◽  
Local Equilibrium ◽  
Grain Structure ◽  
Solid Concentration ◽  
Free Zone ◽  
Cu Alloys ◽  
Liquid Film Migration

Microstructural evolution in the presence of liquid film migration (LFM) is simulated for Al-Cu alloys using a cellular automaton (CA) model. Simulations are performed for the microstructural evolution and concentration distribution in an Al-4 wt.%Cu alloy with initially equiaxed grain structures holding in a temperature gradient. A slight deviation from local equilibrium, estimated from experimental data, is considered to be the driving force for LFM. The direction of LFM is triggered by concentration fluctuations setting a concentration gradient as a further driving force. The simulation successfully reproduces the experimentally observed microstructures generated by LFM accompanied by a particle free zone behind the liquid film. The solid concentration in the particle free zone is found to be the equilibrium solid concentration. The simulated concentration profile across the migrating liquid film agrees well with experimental measurements. The simulated grain structure becomes coarser and highly elongated after holding in the temperature gradient. The results reveal that the increase in transversal grain width is mainly controlled by LFM, while the grain elongation in longitudinal direction is attributed to both LFM and temperature gradient zone melting. The solid concentration decreases from the initial (supersaturated) composition to the local equilibrium solid concentration corresponding to the local temperature. This article is part of the theme issue 'Transport phenomena in complex systems (part 2)'.

Liquid Film Migration in Aluminium Brazing Sheet?

2006 ◽  
Vol 519-521 ◽  
pp. 1151-1156 ◽  
Author(s):  
A. Wittebrood ◽  
S. Desikan ◽  
R. Boom ◽  
Laurens Katgerman
Keyword(s):  
Free Energy ◽  
Corrosion Resistance ◽  
Liquid Film ◽  
Significant Influence ◽  
Clear Explanation ◽  
Distribution Of Elements ◽  
Essential Properties ◽  
Low Levels ◽  
Number Of Publications ◽  
Liquid Film Migration

From literature and own observations it is known that the clad and core alloys that make up aluminium brazing sheet can show severe interaction during the brazing cycle. This interaction leads to a complete re-distribution of elements, changing essential properties like strength and corrosion resistance. This interaction has been reported many times but up to present time no clear explanation is given why this interaction is actually occurring. There are a number of publications addressing the circumstances under which the interaction is more severe. Chemistry and low levels of strain applied before brazing have a significant influence on the severity of the interaction. As a yet possible mechanism behind the interaction Liquid Film Migration is mentioned. The observations done so far are in line with this described mechanism but no ultimate proof has been given so far. The question why the interaction takes place cannot be answered yet, clearly a change of free energy of the system is involved but the mechanism or mechanisms behind the change is unclear.

On liquid film migration in aluminium–copper alloys

1998 ◽  
Vol 46 (2) ◽  
pp. 511-524 ◽  
Author(s):  
S.W. Barker ◽  
G.R. Purdy
Keyword(s):  
Liquid Film ◽  
Copper Alloys ◽  
Aluminium Copper ◽  
Liquid Film Migration

Phase Equilibration in ZrO2-Y2O3 Alloys by Liquid-Film Migration

1986 ◽  
Vol 69 (3) ◽  
pp. 243-248 ◽  
Author(s):  
R. CHAIM ◽  
A. H. HEUER ◽  
D. G. BRANDON
Keyword(s):  
Liquid Film ◽  
Liquid Film Migration
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