Distribution and prediction of solute in Al-Zn-Mg alloys

The distribution of solute in α-Al matrix of directionally solidified Al-5.3 at.% (12 wt.%) Zn master alloy with additions of 5.5-11.5 at.% (4.6-9.2 wt.%) Mg was determined and predicted according to the model for dendrite solidification of multicomponent alloys with unequal liquid diffusion coefficients. Predictions showed a good agreement with experimental data, especially for Al-5.3 at.% Zn master alloy with Mg contents from 5.5 to 6.5 at.%. Furthermore, solute concentration data was used to predict the maximun amount of τ phase precipitate in α-Al matrix which will impact positively in the electrochemical efficiency properties of Al-Zn-Mg alloys which will be employed for cathodic protection applications.