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Transition from solidification to the first solid/solid transformation during diffusion soldering

Waldemar Wołczyński 1Edward Guzik 2Jolanta Janczak-Rusch 3Dariusz Kopyciński 2Jacenty Kloch 4

1. Polish Academy of Sciences, Institute of Metallurgy and Materials Sciences (IMIM PAN), Reymonta 25, Kraków 30-059, Poland
2. AGH University of Science and Technology (AGH), al. Mickiewicza 30, Kraków 30-059, Poland
3. Empa, Materials Technology and Research (Empa), Überlandstrasse 129, Dübendorf 8600, Switzerland
4. Polish Academy of Sciences, Institute of Mathematics (IM PAN), Św.Tomasza 30, Kraków 31 027, Poland

Abstract

Formation of the Ni-Al-Ni and Fe-Zn-Fe joints in relation to the diffusion soldering is considered. The sequence of appearing intermetallic phases during diffusion soldering is observed by arresting solidification or first solid/solid transformation. The solute segregation measurements are performed to estimate the average solute concentration during solidification and first solid/solid transformation. A competition between metastable phase and stable phase growth during first period of solidification is considered. The period of time for a transformation of the liquid filler metal into technologically justified liquid solute solution is identified and analysed. The birth of the phase second in sequence (for the Ni/Al/Ni joint) or birth of the phase third in sequence (for the Fe/Zn/Fe joint) is revealed and described. The zero number degrees of freedom for both systems Ni/Al/Ni and Fe/Zn/Fe is considered from the view point of the Gibbs phase rule. Some suggestions for a solidification model together with solidification path are proposed. The first solid/solid transformation is observed and related to the previous period of solidification. The maintenance of the average solute content from solidification during the first solid/solid transformation is supposed and analysed. The first solid/solid transformation is described as a kind of chemical reaction and shown experimentally as consumption of the second phase in sequence (for the Ni/Al/Ni joint) or third phase in sequence (for the Fe/Zn/Fe joint) by a dominant phase. The revealed consumption named as a “mantis” phenomenon is an independent behaviour of the system and occurs in sequence after solidification.


 

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Presentation: oral at E-MRS Fall Meeting 2005, Symposium H, by Waldemar Wołczyński
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-04 11:56
Revised:   2009-06-07 00:44