Copper is an important alloy element, which has a certain effect of solid solution strengthening. In addition, CUAL2 precipitated by aging has obvious effect of aging strengthening. The content of copper in aluminum alloy is usually in the range of 2.5% ~ 5% , and the strengthening effect is best when the content of copper is in the range of 4% ~ 6.8% .
Al-si alloy has excellent casting properties and corrosion resistance. In wrought aluminum alloys, the addition of silicon to aluminum alone is limited to welding materials, and the addition of silicon to aluminum also has a certain strengthening effect.
The equilibrium phase diagram of Al-Mg alloy shows that the solubility of Mg in al decreases greatly with decreasing temperature, but the content of MG in most industrial wrought al alloys is less than 6% , and the silicon content is also low, this kind of alloy can not heat treatment strengthen, but weldability is good, corrosion resistance is good, and have medium strength.
Manganese can prevent the recrystallization process of aluminum and aluminum alloys, increase the recrystallization temperature and refine the recrystallized grains. Manganese is an important element of aluminum alloy, which can be added separately to form Al-Mn binary alloy, and more often with other alloy elements, so most aluminum alloys contain manganese.
The solubility of Zn in Al is 31.6% at 275 and 5.6% at 125 for AL-ZN alloy. The addition of zinc to aluminum has limited effect on the strength of aluminum alloy, and has the tendency of stress corrosion cracking, which limits its application. The MG/ZN2 strengthening phase was formed by the addition of Mg and Mg in Al, which had obvious strengthening effect on the alloy. Al-zn-mg-cu alloy is formed by adding copper element on the basis of Al-Zn-Mg. The base strengthening effect of Al-Zn-Mg-cu alloy is the largest among all aluminum alloys, and it is also an important aluminum alloy material in aerospace, aviation and electric power industries.