The main functions of alloying elements and impurity elements in the 4000 series aluminum
(1) Silicon: Silicon is the main alloy component in this series of alloys, with a content of ω(Si)=4.5%~13.5%. Silicon mainly exists in the form of α+Si eutectic and β(Al 3 FeSi) in the alloy. As the silicon content increases, the eutectic increases, the fluidity of the alloy melt increases, and the alloy strength and wear resistance also increase. .
(2) Nickel and iron: Nickel and iron can form an intermetallic compound that is insoluble in aluminum, which can increase the high temperature strength and hardness of the alloy without reducing its linear expansion coefficient.
(3) Copper and magnesium: Copper and magnesium can generate Mg 2 Si, CuAl 2 and S phases to improve the strength of the alloy.
(4) Chromium and titanium: Chromium and titanium can refine grains and improve the air tightness of the alloy.