The modification of β-Al5FeSi phase in Al-Si-Mg-Fe alloys by utilizing recycled beverage can body in casting process
The acicular iron intermetallic compound, β-Al5FeSi, is often quoted as disadvantages in aluminum based alloy ingots because of its brittleness. This undeniable phase, however, is found to show less effects on the ingots properties if trace manganese is added. The modified round ended and Chinese script-like structure showed significant higher ductility. The present work reports results of prospective experiments designed for obtaining shape modification of the iron intermetallic compound exclusively from readily available scrap aluminum cans as a source of manganese. A356 aluminum alloy with 1 wt.% iron and 10 wt. % manganese calculated from recycled aluminum cans was melted in a laboratory furnace. The molten metal was soaked at 800°C for different aging times ranging from 15, 60 to 120 minutes before undergoing the conventional casting process. The produced ingots were characterized concerning their microstructures, hardness and final composition, which allowed estimating the proper aging time for the microstructure improvement. It was observed that the 60 minute-aging time yielded the best modification of 14 micron round ended needle morphology. However, the longer aging time resulted in lower hardness as the result of the obtained Al15(MnFe)3Si2 as a majority phase. © 2016 Trans Tech Publications, Switzerland.