The research shows that about 75% of the fuel consumption is related to the vehicle mass. Reducing the vehicle mass can effectively reduce the fuel consumption and emissions. It can reduce the weight of the whole vehicle and the power transmission load, and achieve better handling performance under lower traction load [2,3]. It is one of the important ways to lighten the weight of automobile to choose the material with lighter weight as far as possible under the requirement of ensuring the strength and rigidity of parts in the year of automobile. Magnesium alloy is the lightest metal structure material in common use at present, and it is rich in reserves, so it becomes the first choice material for automobile to reduce weight and improve its fuel economy and controllability.
The application of magnesium alloy casting in automobile industry has the following advantages:
a. Its density is only 2 / 3 of that of aluminum alloy;
b. The specific strength is higher than that of aluminum alloy and cast iron, slightly lower than that of fiber reinforced plastics with the highest specific strength, which has a certain bearing capacity;
c. The specific stiffness is basically the same as other materials, which can replace aluminum alloy and steel parts;
d. It has good casting performance and dimensional stability, easy to process and low reject rate;
e. It has a good damping coefficient, and the damping amount is greater than aluminum alloy and cast iron. It can reduce the noise when used to make the shell, and reduce the vibration when used to make the seat and wheel rim, so as to improve the safety and comfort of the car;
f. Good anti electromagnetic interference and shielding, reduce noise;
g. It has little environmental pollution and can be reused.