Magnesium aluminium alloy is a kind of alloy, and its density is generally less than 1.8g·cm3. The low density of magnesium and aluminium alloys improves its specific performance. Magnesium-aluminum alloys have good strength, rigidity and dimensional stability.
Due to magnesium's low density, its alloys are also known for their light weight. For example, the elastic modulus at 20°C is 45 Gpa, which is lower than that of aluminum (70 Gpa) and Ti (120 Gpa), but the specific elastic modulus of the three is the same (~26 Gpa). The small mass of magnesium and magnesium alloys makes them have great application prospects in the transportation, aviation and aerospace industries.
physical properties of magnesium aluminium alloy
The melting point of magnesium is 651°C and the boiling point is 1107°C. The vapor pressure of magnesium is very high, 215215.95Pa at 627°C, and 1037.1Pa at 727°C, so magnesium beryllium is extremely volatile.
Application of Mg Al alloy
Magnesium will slowly oxidize in the air, lose its silvery white luster and turn black. If the temperature is increased to above 400 ℃, the oxidation rate of magnesium will increase. After more than 500 ℃, the oxidation rate will be faster, and it will catch fire and burn. At this time, magnesium oxide and a small amount of magnesium nitride will be formed. Magnesium burns very brightly.
- It has been used for photographic lighting in the early days.
- Used to make flares.
- It is used to make incendiary bombs and to ignite materials and equipment in war zones.
- Fireworks are made from magnesium powder, aluminum powder and other raw materials.
- The active electrochemical properties of the magnesium anode make it a self-sacrificing anode, protecting other metals and devices.
chemical properties of magnesium aluminium alloy
Due to its high chemical activity, magnesium metal is one of the metals with the worst corrosion resistance. In acidic, neutral and weak alkaline solutions, it will be corroded and become Mg2+ ions. Various types of atmosphere will have different degrees of corrosion on magnesium. In dry air, a dull loose porous oxide film is formed on its surface. In humid atmosphere, the composition of the resulting product is roughly Mgco3·3H2O+Mgso4·7H2o+Mg(OH)2. The increase of atmospheric humidity, the sulfur dioxide and chloride contained in the atmosphere of the industrial area and marine environment, can aggravate the corrosion of magnesium. Chloride impurities and iron impurities in magnesium will also accelerate the corrosion of magnesium. Therefore, industrially produced magnesium ingots must be passivated, oiled and covered with wax paper.
Application of Mg Al alloy
Magnesium alloy DVD cover: good rigidity, dimensional stability and thermal conductivity are not only lighter and thinner than plastic cover, but also
It also avoids functional failures caused by aging and deformation caused by heat.
Lighter and thinner laptops: Magnesium alloy casing is the first choice, not only because magnesium alloy has good strength, rigidity and dimensional stability, but also excellent electromagnetic shielding and thermal conductivity, which can better protect the computer to work normally and stably for a long time. .
Mobile phone: Magnesium alloy has low density, high strength and good rigidity, which is in line with the requirements of thin and light mobile phones. At the same time, its excellent electromagnetic shielding also reduces the damage of electromagnetic radiation to the human body.
