Effect of Casting Temperature on Microstructure of AlSi9Cu3(Fe) Alloy

AlSi9Cu3(Fe) aluminum alloy is widely used in casting aluminum alloy.Casting temperature is an important process parameter to obtain excellent mechanical properties of hypoeutectic Al-Si alloy.The evolution of Fe-containing intermediate compounds in AlSi9Cu3 (Fe) cast aluminum alloy by testing the α-Fe and β-Fe content at different casting temperatures was studied.AlSi9Cu3 (Fe) alloys with Fe content of about 0.7wt% were prepared at different temperatures ranging from 680 ℃ to 960 ℃ and casting temperature interval of 70 ℃.The results show that the secondary dendrite arm spacing of AlSi9Cu3(Fe) alloy does not change significantly at different casting temperatures.When the casting temperature is higher than 890℃, the precipitation of harmful β-Fe phase is inhibited in a certain extent.At the same time, the bulk or Chinese character shape α-Fe phase becomes the dominant phase of the microstructure.When the casting temperature is high, the equilibrium condition of Fe-rich phase crystallizing into steady β-Fe phase is broken, and the metastable α-Fe phase is more easily formed.