Affect the performance of aluminum alloy eight metals

[China Aluminum Network] The eight elements that affect the performance of aluminum alloys are: vanadium, calcium, lead, tin, antimony, bismuth, bismuth, and sodium; due to the different uses of the finished aluminum coil, they are not processed in the process. The added elements These impurity elements have different melting points, different structures and different aluminum forming compounds, so the impact on the performance of aluminum alloy is not the same.

1. Metallic elements: Influence of copper elements Copper is an important alloying element and has a certain solid-solution strengthening effect. In addition, CuAl2 precipitated during ageing has a significant aging strengthening effect. Copper content in aluminum plates is usually between 2.5% and 5%, and the copper content is between 4% and 6.8%. The effect of strengthening is good, so the copper content of most hard aluminum alloys is within this range.

2. Metal elements: Effect of silicon elements Phase diagram of Al-Mg2Si alloy-based alloys The greater solubility of aluminum-rich Mg2Si in aluminum is 1.85%, and the deceleration is small with a decrease in temperature. In deformed aluminum alloys, silicon alone is added. The aluminum plate is limited to the welding material, and the addition of silicon to aluminum also has a certain strengthening effect.

3, metal elements: the impact of magnesium Magnesium on the strengthening of aluminum is significant, each increase of 1% magnesium, tensile strength increased about 34Mpa. If you add 1% or less of manganese, it may enhance the strengthening effect. Therefore, after adding manganese, magnesium content can be reduced, and hot cracking tendency can be reduced. In addition, manganese can also cause average precipitation of Mg5Al8 compound and improve corrosion resistance and welding performance.

4. Metal elements: Effect of manganese elements The greater solubility of manganese in solid solutions is 1.82%. The alloy strength increases with the increase of solubility, and when the manganese content is 0.8%, the elongation reaches a large value. Al-Mn alloys are alloys of short and hard age, ie they are not heat-treatable.

5, metal elements: the impact of zinc elements Al-Zn alloy system equilibrium phase diagram Al-rich sector 275 when the solubility of zinc in aluminum is 31.6%, and at 125 o'clock, its solubility dropped to 5.6%. When zinc is added to aluminum alone, the strength of the aluminum alloy under the premise of deformation is very limited. At the same time, there is stress corrosion cracking and tendency, which limits its application.

6, metal elements: the influence of iron and silicon iron in Al-Cu-Mg-Ni-Fe series forging aluminum alloy, silicon in Al-Mg-Si series forged aluminum and Al-Si series electrodes and aluminum-silicon forging alloy Both of them are added as alloying elements. Silicon and iron are common impurity elements in the base aluminum alloy, which has a significant effect on the alloy performance. They mainly exist as FeCl3 and free silicon. When silicon is larger than iron, β-FeSiAl3 (or Fe2Si2Al9) phases are formed, and when iron is larger than silicon, α-Fe2SiAl8 (or Fe3Si2Al12) is formed. When the proportion of iron and silicon is not appropriate, cracks may be caused in the casting. When the iron content in the cast aluminum is too high, the casting may be brittle.

7. Metallic Elements: Effects of Titanium and Boron Titanium is a commonly used additive element in aluminum alloys and is added in the form of Al-Ti or Al-Ti-B master alloys. Titanium forms a TiAl2 phase with aluminum and becomes a non-spontaneous core at the time of crystallization, and it functions to refine the forged structure and the weld structure. When the Al-Ti alloy produces a package reaction, the critical content of titanium is about 0.15%, and if there is boron, the deceleration is as small as 0.01%.

8. Metallic elements: effects of chromium and niobium Chromium forms intermetallic compounds such as (CrFe)Al7 and (CrMn)Al12 in the aluminum plate, hinders the nucleation and growth of recrystallization, and has a certain strengthening effect on the alloy. Improve alloy toughness and reduce stress erosion cracking sensitivity. However, the sensitivity of quenching is increased at the venue, and the anodic oxide film is yellow. The addition of chromium in the aluminum alloy generally does not exceed 0.35%, and decreases with the increase of the transition elements in the alloy. The addition of 0.015% to the aluminum alloy for extrusion ~0.03% 锶, the β-AlFeSi phase in the ingot transforms into the Chinese character α-AlFeSi phase, reduces the average ingot time by 60% to 70%, improves the mechanical properties and plasticity of the material, and improves the surface roughness of the product. . For the high silicon (10%~13%) deformed aluminum alloy added 0.02%~0.07% niobium element, the primary crystal can be reduced to a lower limit, the mechanical performance is also significantly improved, the tensile strength бb is improved from 233MPa to 236MPa, yielding The strength б0.2 increases from 204 MPa to 210 MPa, and the elongation б5 increases from 9% to 12%. Adding niobium to the hypereutectic Al-Si alloy can reduce the size of primary silicon particles, improve the plastic processing ability, and can be successfully hot-rolled and cold-rolled.

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