Magnesium is one of the light metal elements, the specific gravity of magnesium is 1.74g/cm3, magnesium alloy is 36% lighter than aluminum alloy, 73% lighter than zinc alloy, and 77% lighter than steel.
Magnesium has the advantages of high specific strength and stiffness, good thermal conductivity, good electromagnetic shielding, damping, vibration reduction, cutting and low processing cost, processing energy is only 70% of aluminum alloy and easy recovery.
Magnesium alloy is an alloy composed of magnesium and other elements.
The main alloying elements are aluminum, zinc, manganese, cerium, thorium and a small amount of zirconium or cadmium. At present, the most widely used aluminum alloy is magnesium, followed by magnesium manganese alloy and magnesium zinc zirconium alloy.
Mechanical properties of magnesium
Compared with die-cast aluminum alloy, magnesium has higher mechanical properties as well as the physical properties mentioned above. The strength and stiffness of magnesium are better than that of plastic, and the elongation and impact resistance of magnesium are better than that of die-cast aluminum alloy.
Defects in the mechanical properties of magnesium
Magnesium is much less strong and hard than steel. It also has lower tensile and fatigue strength than aluminum, as shown in Table 3 below. However, its performance to weight ratio is significantly better than that of the other materials compared. In absolute terms, steel performs the best of all automotive materials.
But the yield strength ratio of magnesium is twice that of steel and the modulus ratio is almost the same. Better yet, magnesium components can be designed and cast in a manner that mitigates the adverse effects of low material performance by changing cross sections, placing stiffeners and improving surface characteristics to ensure quality and durability of magnesium components.
Advantages of magnesium processing properties
Magnesium has good machinability, that is to say it has good casting performance.
It is cheap to make compared to other materials, and it is important to note that although the price per kilogram of magnesium ingots is more expensive than that of aluminum and iron, the price per volume of finished magnesium is almost the same.
Magnesium’s physicochemical properties make it more suitable than aluminum for die-casting large components. Magnesium has only 2/3 of the potential melting heat per unit volume of aluminum, only 3/4 of the specific heat of aluminum, and has a very low iron solubility.
These characteristics enable magnesium die casting to achieve nearly the same production cost/kg as aluminum. When combined with the highly efficient HOT RUNNER technology, magnesium die-cast components can be produced at a much lower cost than aluminum.