Effect of Fe and Sr in the evolution of iron based intermetallic phases in Al-Si hypoeutectic alloys

The main aim of the study is to understand the formation of the iron bearing intermetallic phases and the effect of Sr addition on them in the Al-Si hypoeutectic alloys. This study has methodically characterized the iron based intermetallic phases evolving during solidification of the Al-7 wt%Si binary alloy as a function of composition of Fe (0.1,0.2, 0.35,0.5 and 0.8 wt%), Sr (0 and 200 ppm) and cooling rates (0.1, 1 and 50 Ks^-1). The samples were analyzed by using the thermal data obtained during solidification and various microscopy techniques. The Al-Si-Fe intermetallic phase compositions were analyzed by Energy Dispersive X-Ray Spectrometer (EDX) and it was observed that there is anomalous evolution of certain Al-Si-Fe intermetallic phases in both alloys with and without Sr addition. The phases evolving in alloys without Sr is different from that with Sr in them. Copyright © 2013 MS&T'13®.