Eight metal elements affecting the properties of aluminum alloy（1）

           The eight major elements that affect the performance of aluminum alloys are: vanadium, calcium, lead, tin, bismuth, antimony, beryllium, sodium and other metal elements. Because the use of the finished aluminum coil is different, these impurity elements are added during the processing. Due to the different melting points, different structures and different compounds formed by aluminum, the effects on the properties of aluminum alloys are also different.

1. Metal element: the influence of copper element

　　Copper is an important alloy element and has a certain solid solution strengthening effect. In addition, CuAl2 precipitated by aging has a significant aging strengthening effect. The copper content in the aluminum plate is usually 2.5%-5%, and the strengthening effect is best when the copper content is 4% to 6.8%, so the copper content of most hard aluminum alloys is in this range.

2. Metal elements: the influence of silicon

        Al-Mg2Si alloy series alloy equilibrium phase diagram The maximum solubility of Mg2Si in aluminum in the aluminum-rich sector is 1.85%, and the deceleration is small with the decrease of temperature. In deformed aluminum alloys, the addition of silicon alone to the aluminum plate is limited to welding materials, and the addition of silicon to aluminum It also has a certain strengthening effect.

3. Metal elements: the influence of magnesium

　　The strengthening of aluminum by magnesium is significant. For every increase of 1% of magnesium, the tensile strength will increase by approximately 34MPa. If adding less than 1% manganese, the strengthening effect may be added. Therefore, adding manganese can reduce the magnesium content, and at the same time reduce the tendency of hot cracking. In addition, manganese can also make the Mg5Al8 compound evenly precipitate, improving the corrosion resistance and welding performance.

4. Metal elements: the influence of manganese

         The maximum solubility of manganese in solid solution is 1.82%. The strength of the alloy increases with the increase in solubility, and the elongation reaches the maximum when the manganese content is 0.8%. Al-Mn alloy is long and short age hardening alloy, that is, it cannot be strengthened by heat treatment.

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