Preparation of the initial solid–liquid interface and melt in directional solidification of Al–18at%Ni peritectic alloy

Influence of thermal stabilization on the solute concentration of the melt in directional solidification

“…[6] and are only outlined here. As-cast Al-25 at%Ni alloy rods of 3 mm in diameter and length of 100 mm were partially melted in a Bridgmantype furnace and submitted to thermal stabilization ranging from 0 to 2 h. The measured temperature gradient in the mushy zone is about 2671 K/mm.…”

“…In combination with previous work [6], microstructure and composition evolution of the mushy zone of Al-Ni peritectic alloys in a temperature gradient is characterized. Second, an analytical model is proposed to evaluate the solute concentration of the melt in directional solidified Al-Ni peritectic alloys after thermal stabilization.…”

“…However, in real experimental situation, the solidification starts on a prepared state, which results from a thermal stabilization stage following the directional melting process. The initial state has been characterized in previous work [2][3][4][5][6]. It is found that the initial state strongly departs from that assumed in the models.…”

“…With thermal stabilization time increase, the mushy zone is subjected to both microstructural and compositional changes. It has been observed that the solute concentration of the melt after thermal stabilization differs from the initial nominal composition of the rod in Al-Li, Al-Ni hypoeutectic alloys [2] and Al-Ni [6] hypo-peritectic alloys.…”

Diffusion in a temperature gradient – A single cycle method to determine frequency factor and activation energy of solid diffusion coefficients in alloys

“…Equilibration at the solid/liquid interfaces leads to a concentration gradient according to the local solidus/liquidus concentration and mass transport of solute toward higher temperatures [18,19]. Reduction of solute content due to the mass transport out of the mushy-zone leads to its complete re-solidification during holding in the temperature gradient [18][19][20][21][22][23][24]. After a specific holding time that can be empirically determined or simulated [25], depending on alloy composition and temperature gradient eventually a planar solid/liquid interface develops.…”