Views: 0 Author: Site Editor Publish Time: 2022-04-26 Origin: Site
Aluminum alloys exhibit different properties due to the addition of different metal elements. Among the various metal elements, the elements that affect the performance of aluminum alloy are copper (Cu), magnesium (Mg), silicon (Si), iron (Fe), manganese (Mn), nickel (Ni), zinc (Zn) and so on. Today, let's talk about the influence of these metal elements on the performance of aluminum alloy.
1. Copper (Cu)
Copper is an important alloying element in aluminum alloy, which has a certain solution strengthening effect. In addition, the aging precipitated CuAl2 has a significant aging strengthening effect.
Advantages: solid solution strengthening and aging strengthening effect is good, the best strengthening effect is when the copper content is 4% to 6.8%, so most of the duralumin copper content is in this range. Increase the copper content, improve the fluidity of the alloy, tensile strength and hardness, so that the mechanical properties can be improved, machinability becomes better.
Disadvantages: reduced corrosion resistance and plasticity, increase hot crack tendency.
2. Magnesium (Mg)
The strengthening effect of magnesium on aluminum is significant, and the tensile strength increases about 34MPa with every 1% increase of magnesium. Reinforcement may be supplemented if less than 1% manganese is added. Therefore, the addition of manganese can reduce the magnesium content, and reduce the tendency of hot cracking. In addition, manganese can also make the Average precipitation of Mg5Alg compounds, improve the corrosion resistance and welding performance.
Advantages: improve tensile strength and yield limit, improve the machinability of alloy.
Disadvantages: Mg2Si can make castings brittle.
3. The silicon (Si)
The maximum solubility of Mg2Si in aluminum is 1.85%, and it decreases with the decrease of temperature. In the deformed aluminum alloy, the addition of silicon to the aluminum plate is only the welding material, and the addition of silicon to aluminum also has a certain strengthening effect.
Advantages: improve the casting performance of the alloy. Silicon and aluminum can form a solid solution, which can improve the alloy's high temperature modeling, reduce shrinkage, no hot crack tendency. Improves tensile strength, hardness, machinability and strength at high temperature while reducing elongation.
Disadvantages: Crystallized silicon (Si) is prone to hard points of free silicon, so that the machinability becomes poor. High silicon aluminum alloy has serious corrosion effect on the crucible of casting.
4. Iron (Fe)
Advantages: aluminum alloy adhesion to the mold is very strong, especially strong when the iron content is below 0.6%, that is, it is not easy to demoulding phenomenon. When the fe content exceeds 0.6%, the adhesion phenomenon is greatly reduced.
Disadvantages: aluminum alloy iron content is too high, iron to FeAl3, Fe2AIz and AI-Si-Fe flake or needle-like organization exists in the alloy, the formation of metal compounds, forming a hard point. This kind of organization will also reduce the mechanical properties, increase the hot cracking, so that the casting brittleness, and iron (Fe) content over 1.2%, reduce the alloy fluidity, damage the quality of the casting, shorten the life of metal components in the die casting equipment.
5. Manganese (Mn)
The maximum solubility of manganese in solid solution is 1.82%. The strength of the alloy increases with the increase of solubility, and the elongation reaches the maximum when the manganese content is 08%. Ai-mn alloy long and short aging hardening alloy, that is, can not be heat treatment strengthening.
Advantages: alloy strength increases with increasing solubility. The maximum elongation was achieved when the manganese content was 0.8%. Manganese (Mn) can prevent the recrystallization of aluminum alloy, increase the recrystallization temperature, and refine the recrystallized grain significantly. The refinement of recrystallized grain is mainly hindered by the dispersion of MnAlg compound. Another function of MnAlg is to dissolve impurity iron (Fe) and form (Fe, Mn) Alg, so that the sheet or needle-like tissue formed by iron in aluminum alloy becomes fine crystal structure, reducing the harmful effect of iron.
Disadvantages: Manganese content is too high, will cause segregation.
6. Nickel (Ni)
Advantages: it has the tendency to increase tensile strength and hardness, and has a great influence on corrosion resistance.
Disadvantages: Reduced corrosion resistance and thermal conductivity.
7. Zinc (zinc)
Advantages: zinc and magnesium are added to aluminum at the same time to form strengthening phase Mg/Zn2, which will have obvious strengthening effect on the combination.
Disadvantages: stress corrosion cracking tendency.