Magnesium alloy
Just to know about the magnesium alloys in the feild of technology, magnesium alloys are alloys based on magnesium with other elements added. The main alloying elements are aluminum, zinc, manganese, cerium, thorium, and a small amount of zirconium or cadmium. At present, magnesium alloy is the most widely used, followed by magnesium manganese alloy and magnesium zinc alloy. Magnesium alloys can be widely used in automotive, electronics, textile, construction and military fields due to their excellent casting, extrusion, cutting and bending properties.
The melting point of magnesium alloy is 650℃, the melting point is lower than that of aluminum alloy, and the die casting performance is good. The tensile strength of magnesium alloy castings is equivalent to that of aluminum alloy castings, generally up to 250MPa and up to more than 600 MPa.
Magnesium alloy has low density (about 1.8g/cm3) and high strength. Magnesium alloy is the lightest metal structure material with a specific gravity of only 1.8, 2/3 of aluminum, and 1/4 of iron, respectively, and a specific strength of up to 133, which makes magnesium alloy can be used as a high-strength material. The specific strength of high-strength magnesium alloys is even comparable to that of titanium.
Magnesium alloy has a large elastic modulus and good shock absorption. In the elastic range, magnesium alloy absorbs half more energy than aluminum alloy when subjected to impact load, so magnesium alloy has good seismic noise reduction performance.
Magnesium alloy has good die-casting performance, the minimum wall thickness of die casting can be up to 0.5mm, suitable for manufacturing various automotive die casting parts. The magnesium alloy parts have high stability, and the casting parts have high dimensional precision, which can be machined with high precision.
The heat dissipation of magnesium alloy has absolute advantages over alloy. For the heat sink of magnesium alloy and aluminum alloy material of the same volume and shape, the heat (temperature) produced by a heat source of magnesium alloy is more easily
transferred from the root of the heat sink to the top of the speed than aluminum alloy, and the top is easier to reach at a higher temperature.
However, the linear expansion coefficient of magnesium alloy is very large, reaching 25-26 μm/m℃, while that of aluminum alloy is 23 μm/m℃, brass about 20 μm/m℃, structural steel about 12 μm/m℃, cast iron about 10μm/m℃, rock (granite, marble, etc.) only 5-9 μm/m℃, glass 5-11 μm/m℃. The influence of temperature on structure size must be considered when applied in a heat source.
Application examples of magnesium alloy: generally medium and high-end and professional digital SLR cameras adopt magnesium alloy as the skeleton, making it durable and feel good; Mobile phones, and laptop cases; Magnesium alloys are used in the housing and cooling parts of computers and projectors that generate high temperature inside; Automotive steering wheel, steering bracket, brake bracket, seat frame, mirror bracket, distribution bracket and other requirements of light-weight and high strength structural parts.
According to the forming method, it can be divided into two categories: deformed magnesium alloy and cast magnesium alloy.
Magnesium alloy grades are represented by letters + numbers + letters. The preceding letters are the codes of the most important alloy elements (as specified in the following table), and the following numbers are the average values of the upper and lower limits of the most important alloy elements. The last letter of the alphabet is the identification code used to identify different alloys with different specific elements or slightly different elements' content.
The common grades of magnesium alloys are AZ31B, AZ31S, AZ31T, AZ40M, AZ41M, AZ61A, AZ61M, AZ61S, AZ62M, AZ63B, AZ80A, AZ80M, AZ80S, AZ91D, AM60B, AM50A, M1C, M2M, M2S, and ZK61 M, ZK61S, ME20M, LZ91, LZ61, LZ121, LA141, LA191, LAZ933, LA81, LA91, LAZ931, MA18, MA21, MA14, and so on.
