Model for intermetallic phase and intermetallic compound solidification during diffusion soldering
|Waldemar Wołczyński 2, Jacenty Kloch 5, Krzysztof J. Kurzydlowski 1, Jolanta Janczak-Rusch 4, Edward Guzik 3|
1. Warsaw University of Technology, Faculty of Materials Science and Engineering (InMat), Wołoska 141, Warszawa 02-507, Poland
Two modes of calculation are presented for both intermetallic phase and intermetallic compound formation during solidification. The presented equations consider a solute microsegregation resulting from partitioning, primary solute redistribution resulting from back-diffusion, secondary solute redistribution required by peritectic reaction and formation of intermetallic phase/compound resulting from peritectic reactions. The formulated set of equations is referred to the concept of undercooled liquid of the selected initial solute concentration formed due to dissolution of the liquid filler metal into the substrate. The solidification path is precisely defined in a given equilibrium phase diagram. The solidification path is accomplished within the infinitesimally small amount of the undercooled liquid, , according to the concept. The solidification occurs at the front of each growing sub-layer so that the undercooled liquid is forced to move from the substrate towards the axis of symmetry of the forming joint. The formulated equations realize the idea of moving undercooled liquid and are able to reproduce both amount of growing sub-layers as well as solute redistribution across the forming joint for which solidification was arrested. The confrontation of both theoretically predicted and measured profile of solute redistribution is shown for two solders Ni/Al/Ni and Fe/Zn/Fe. The current model is universal one and can also be applied to metastable phase diagram in order to emphasize that diffusion soldering occurs under metastable conditions.
Presentation: poster at E-MRS Fall Meeting 2005, Symposium H, by Waldemar Wołczyński
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-05-10 07:17 Revised: 2009-06-07 00:44