Shrinkage porosity and segregation of semi solid die casting thick wall products

Aluminum is the most abundant metal element in the earth’s crust. Although the large-scale preparation and industrial application of aluminum have only developed for 130 years, aluminum has the advantages of low density and low melting point. Aluminum and aluminum alloy has become the second metal with consumption less than that of steel and has been widely used in various industries.

People’s awareness of energy conservation and emission reduction is gradually enhanced. China has taken the construction of ecological civilization as an important part of the 13th five year plan. Automobile lightweight is an important way to achieve green development of energy conservation and emission reduction. (3) the ways of automobile lightweight mainly include:

(1) Lightweight design, that is to optimize the internal space structure of the car to reduce the weight of the vehicle;

(2) Material lightweight means using alloy with lower density to replace traditional steel parts under the condition of ensuring the performance of parts, such as “replacing steel with aluminum”, in which material lightweight is an important means adopted in the research of automobile lightweight.

Research shows that every 10% reduction in vehicle weight can reduce fuel consumption by 6% – 8% and reduce carbon dioxide emission by 13%. At present, the United States, Japan and Germany have become the countries with the largest amount of aluminum in automobiles, while China still has a lot of room for improvement in this field. Therefore, it has become an important development trend of automobile industry to vigorously promote the development of automobile lightweight and increase the aluminum consumption of automobile.

The key problem in the process of “replacing steel with aluminum” in automobile is how to make the mechanical properties of aluminum alloy parts similar to those of traditional steel products under the condition of low cost. Semi solid forming technology can produce aluminum alloy products with mechanical properties similar to forgings at low cost as far as possible. At present, this technology has been applied in the field of automobile transportation and has a wide application prospect.