The influence of AlTi5B1 grain refinement and the cooling rate on the formation behaviour of Fe-rich compounds in secondary AlSi8Cu3 alloys

The role of AlTi5B1 grain refinement and the cooling rate on the formation behaviour of Fe-rich compounds in secondary AlSi8Cu3 alloys have been studied. Metallographic and thermal analysis techniques have been used to characterize the precipitation behaviour of Fe-bearing precipitates. The results indicate how the Al- Ti-B grain refinement can influence the precipitation sequence of Fe-bearing phases by promoting the crystallization of \u3b2-Al5FeSi over \u3b1-Al15(FeMn)3Si2 in the microstructure. The formation of \u3b2-Al5FeSi intermetallics occurs nucleating from TiB2 particles, the efficiency of which seems to be further affected by the cooling rate