Fig. 1. The phase diagram of Al-Si shows the eutectic point.


Fig. 2. This phase diagram shows the shift of eutectic point due to solid solution of Ba in Si as imposed in the Al-Si phase diagram.


strength and ductility not currently seen in existing cast alloys. These alloys also may be further strength- ened by heat treatment. In the research paper, “Permanent Mold Castings of High-Strength and High Ductility Ba-Treated Hypoeu- tectic Al-Si Alloys,” a research team


investigated how barium treatments aff ected aluminum-silicon alloys in an eff ort to develop advanced alloys that could be cast.


Question


Can the addition of barium to aluminum-silicon cast alloys increase


ductility and strength in as-cast and/or T6 heat-treated conditions?


1


Background Based upon the Al-Si


binary system shown in Figure 1, alloys with hypo- eutectic composition have a


40 | METAL CASTING DESIGN & PURCHASING | Nov/Dec 2015


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