Transition from solidification to the first solid/solid transformation during diffusion soldering
|Waldemar Wołczyński 1, Edward Guzik 2, Jolanta Janczak-Rusch 3, Dariusz Kopyciński 2, Jacenty Kloch 4|
1. Polish Academy of Sciences, Institute of Metallurgy and Materials Sciences (IMIM PAN), Reymonta 25, Kraków 30-059, Poland
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.
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