Using directional solidification to determine solid/liquid equilibria in multicomponent phase diagrams

An experimental method to determine solid/liquid equilibria (tie-lines) in multicomponent alloys has been optimized. A sequence of tie-lines along the solidification path of an alloy can be determined with a single experiment. The method is based on directional solidification in the presence of strong forced convection. A combination of measurements of concentration profiles with mass balance calculations is used to determine liquidus and solidus concentrations. The experimental and evaluation methods are validated using alloys of well-known binary Al-based systems. It is shown that the conditions necessary for the experiment were achieved with the presented set-up. Good agreement is found for the binary test cases; effects that only occur in higher component alloys were observed in a quinary alloy.