Simple Introduction of Magnesium Alloys
1. The properties of magnesium alloy
1.1 Good structural material because of its light weight, high specific strength and high specific stiffness. Its density is 1.74g/cm³, two thirds of aluminum alloy's and a quarter of steel's, but its spstrength and stiffness are better than those of the other two and far better than that of the engineering plastics.
1.2 No siderophile affinity. It does not have chemical reaction with chromium, and has slight one with manganous.
1.3 Born with the competence of shock absorption and reduction of noise, so it can cut down the noise of items whose exterior is made by magnesium alloy, and absorb the shaking of exercise equipment to prolong their life span.
1.4 Nonmagnetic. It is applied to electric products thanks to its good performance of screening electromagnetic wave.
1.5 High stability in size, which means its size does not vary much because of the change of temperature or humidity as time goes on.
1.6 Good radiation. Its radiation is only inferior to aluminum alloy.
1.7 Praised performance in die casting. The thickness of magnesium die casting parts can be as thin as 0.6 mm.
1.8 Wonderful cutting performance (its cutting power is a half of that of aluminum alloy). It requires low cutting power but pays back good cutting performance. But it has oxytropism so care should be taken.
1.9 Good recyclale material that can be 100% recycled. It can be melt at low melting temperature (590-650 degree), and only need a quarter of the first producing energy when recycled.
1.10 Not resistant to corrosion. It will be oxidized and corroded when it is exposed in the air, so the surface treatment is required for magnesium parts.
1.11 Low specific heat and low melting point, so it cools at a fast rate when die casted.
2. Chemical element of main magnesium alloys
MA AL Zn Mn Si Fe Cu Ni rare element others
AZ91D 8.3~9.7 0.35~1.0 0.15~0.5 0 0.1max 0.005
Magnesium Alloys Applied to Automotive Industry