What is the influence of Rare Earth on Properties of Aluminum and Aluminum Alloys?>

1. Influence of rare earth on comprehensive mechanical properties of alloys

The addition of an appropriate amount of rare earth can improve the comprehensive mechanical properties of the alloy such as strength, hardness, elongation, fracture toughness and wear resistance. When 0.3% RE is added to cast aluminum ZL10 series alloy, its σb is increased from 205.9MPa to 274MPa, and HB is increased from 80 to 108; 0.42% Sc is added to 7005 alloy, its σb is increased from 314MPa to 414MPa, and σ0.2 is increased from 282MPa to 108MPa. 378MPa, the plasticity increases from 6.8% to 10.1%, and the high temperature stability is significantly enhanced; La and Ce can significantly improve the superplasticity of the alloy. Adding 0.14% to 0.64% La to the Al-6Mg-0.5Mn alloy, its superplasticity increases from 430 % increased to 800% to 1000%; a systematic study of Al-Sc alloys found that adding an appropriate amount of Sc can greatly improve the yield strength and ultimate tensile strength of alloy materials. Al-Si7-Mg0.8 alloy has typical brittle cleavage fracture without RE, but after adding 0.3% RE, obvious dimple-like structure appears in the fracture, indicating that it has good toughness and ductility.

2. Influence of rare earth on high temperature properties of alloys

Adding a certain amount of rare earth to the aluminum alloy can effectively improve the high temperature oxidation resistance of the aluminum alloy. For example, adding 1% to 1.5% of mixed rare earth to the cast Al-Si eutectic alloy increases the high temperature strength by 33%, the high temperature endurance strength (300℃, 1000 hours) increases by 44%, and the wear resistance and high temperature are stable The high temperature performance of the alloy can be improved by adding La, Ce, Y and misch metal to the cast Al-Cu alloy; the rapidly solidified Al-8.4%Fe-3.4%Ce alloy can work for a long time below 400℃ , greatly improving the working temperature of aluminum alloys; adding Sc to Al-Mg-Si alloys forms Al3Sc particles that are not easy to coarsen and coherent with the matrix at high temperatures, so that the alloys remain in the annealing process. The crystal structure greatly improves the high temperature performance of the alloy.

3. Influence of rare earth on optical properties of alloys

Adding rare earth to aluminum alloy can change the structure of its surface oxide film, making the surface brighter and more beautiful. When 0.12%-0.25% RE is added to the aluminum alloy, the reflectivity of the oxidized and colored rare earth 6063 profile is as high as 92%; when 0.1%-0.3% RE is added to the Al-Mg cast aluminum alloy, the alloy can be Get the best surface finish and gloss persistence.

4. Influence of rare earth on electrical properties of alloys

Adding rare earth to high-purity aluminum is detrimental to the electrical conductivity of the alloy, but adding an appropriate amount of RE to industrial pure aluminum and Al-Mg-Si conductive alloys can improve the electrical conductivity to a certain extent. The experimental results show that adding 0.2% RE in aluminum can increase the electrical conductivity by 2% to 3%. Adding a small amount of yttrium-rich rare earth to Al-Zr alloy can improve the conductivity of the alloy, which has been used by most domestic wire factories; adding trace rare earth to high-purity aluminum to make Al-RE foil capacitors for 25kV products Among them, the capacitance index is increased by 1 times, the unit volume capacity is increased by 5 times, the weight is reduced by 47%, and the capacitor volume is significantly reduced.

5. Influence of rare earth on corrosion resistance of alloys

In some use environments, especially in the presence of chloride ions, the alloy is extremely susceptible to corrosion, crevice corrosion, stress corrosion and corrosion fatigue. In order to improve the corrosion resistance of aluminum alloys, many studies have been carried out, and it has been found that adding an appropriate amount of rare earth to aluminum alloys can effectively improve its corrosion resistance. The samples prepared by adding different amounts (0.1% to 0.5%) of mixed rare earths to aluminum were immersed in brine and artificial seawater for 3 consecutive years. The results show that adding a small amount of rare earth to aluminum can improve the corrosion resistance of aluminum. The corrosion resistance in brine and artificial seawater is 24% and 32% higher than that of aluminum respectively; by chemical vapor method, adding rare earth multi-component infiltration agent (La, Ce, etc.) can form a rare earth conversion film on the surface of 2024 alloy, The surface electrode potential of the aluminum alloy tends to be uniform, and the resistance to intergranular corrosion and stress corrosion is improved; adding La to the high-Mg aluminum alloy can significantly improve the marine corrosion resistance of the alloy; adding 1.5% to 2.5% to the aluminum alloy %Nd, which can improve the high temperature performance, air tightness and corrosion resistance of alloys, and is widely used as aerospace materials.