The Effect of In Situ Intermetallic Formation on Al-Sn Foaming Behavior

The effect of in situ intermetallic formation on the foaming behavior of Al-3 wt pct Sn alloy has been investigated by introducing five different alloying elements-Co, Mg, Mn, Ni, and Ti. The alloying elements were designed, using thermodynamic calculations, to form various intermetallic phases which are (i) stable until final foaming temperature and (ii) dissolved during the foaming process. Thermal analysis using DSC was carried out to characterize the formation and dissolution of intermetallic phases during the foaming process. The foaming tests of the Al-3 wt pct Sn-X alloy were carried out using a mechanical expandometer and the macrostructure of the foam was scanned with an X-ray tomographer. It is found that the foaming behavior and foam stability of Al-3 wt pct Sn alloy can be actively controlled by the alloying elements.