Library Subscription: Guest
ICHMT DL Home Current Year Archives Executive Committee International Centre for Heat and Mass Transfer

Non-Equilibrium Diffusion-Controlled Melting and Re-Solidification of Thin Metal Layers on a Reactive Substrate

DOI: 10.1615/ICHMT.2004.IntThermSciSemin.210
pages 217-222

Hui Zhao
Department of Mechanical Engineering and University of Kentucky Center for Manufacturing, College of Engineering, Lexington, KY 40506, USA

Dusan P. Sekulic
University of Kentucky Institute of Fluid, Thermal and Chemical Engineering University of Novi Sad, 21000 Novi Sad, Yugoslavia


The paper offers an approach to a prediction of the residue formation inherent to melting of micro layers of molten aluminum alloy and a subsequent reactive flow governed by surface tension.
The phenomenon studied is associated with materials' processing during controlled atmosphere brazing of aluminum. The model assumes that a non-equilibrium diffusion of Silicon, present in an Al + Si clad of a brazing sheet, has a two-fold role. First, a solid state Si diffusion prior to melting and across the clad-core interface of a composite brazing sheet takes place. Concurrently and subsequently, Si diffusion within clad controls the melting process. Both processes are essential for clad residue formation. The approach advocated in this paper leads to a prediction of the residue formation through a modeling of the non-equilibrium diffusion-controlled melting. A heuristic interpretation of physical mechanisms was discussed and a related mathematical model devised. The model was solved numerically in terms of Si concentration distributions for a moving boundary problem and corroborated with empirical data. Empirical data were gathered using an experimental controlled atmosphere brazing facility.
The results of the modeling and their corroboration with the experimental data indicate a strong dependence of residue formations on the pre-melting state of the clad, in particular on the grain size within Al-clad matrix. A good agreement between numerically predicted residue mass and experimental findings is documented in detail.

ICHMT Digital Library

Bow shocks on a jet-like solid body shape. Thermal Sciences 2004, 2004. Pulsed, supersonic fuel jets - their characteristics and potential for improved diesel engine injection. PULSED, SUPERSONIC FUEL JETS - THEIR CHARACTERISTICS AND POTENTIAL FOR IMPROVED DIESEL ENGINE INJECTION
View of engine compartment components (left). Plots of temperature distributions in centreplane, forward of engine (right). CHT-04 - Advances in Computational Heat Transfer III, 2004. Devel... DEVELOPMENT AND CURRENT STATUS OF INDUSTRIAL THERMOFLUIDS CFD ANALYSIS
Pratt & Whitney's F-135 Joint Strike Fighter Engine under test in Florida is a 3600F class jet engine. TURBINE-09, 2009. Turbine airfoil leading edge stagnation aerodynamics and heat transfe... TURBINE AIRFOIL LEADING EDGE STAGNATION AERODYNAMICS AND HEAT TRANSFER - A REVIEW
Refractive index reconstructed field. (a) Second iteration. (b) Fourth iteration. Radiative Transfer - VI, 2010. Theoretical development for refractive index reconstruction from a radiative ... THEORETICAL DEVELOPMENT FOR REFRACTIVE INDEX RECONSTRUCTION FROM A RADIATIVE TRANSFER EQUATION-BASED ALGORITHM
Two inclusion test, four collimated sources. Radiative Transfer - VI, 2010. New developments in frequency domain optical tomography. Part II. Application with a L-BFGS associated to an inexa... NEW DEVELOPMENTS IN FREQUENCY DOMAIN OPTICAL TOMOGRAPHY. PART II. APPLICATION WITH A L-BFGS ASSOCIATED TO AN INEXACT LINE SEARCH