Improvement Of Strength And Toughness Of Casting Aluminium Alloy ZL107 With Minim Alloy Element

As production design pay more attention to lightening requirements, the usage quantity of aluminium alloy has been growing in casting industry. Now, in order to reduce fuel consumption and improve power utilization rate, it has become a long trend of development to use aluminium/ magnesium alloy casting parts in stead of steel and iron casting parts in automotive industry. Cast aluminium-silicon alloy is the most widely used aluminium alloy with most usage quantity due to its good cast performance. The alloy of ZL107 is one of the widely industry used alloys especially in automotive industry because it has not only good cast performance, but also good air seal performance and relatively better comprehensive performance. But the mechanical performance and corrosion resistance of ZL107 is relatively worse, and machinability is poor and can't meet the requirement of some parts with relatively high performance requirements, its use extent is undoubtedly limited. So it has been a proposition before casting practitioner how to improve the comprehensive performance and extend its application extent while keep is fine cast performance.This proposition starts from the theory of improvement of aluminium alloy strength and toughness and obtains a new kind of cast alloy of aluminium, silicon and copper whose comprehensive performances are better than ZL107, by optimizing composition through adding alloy elements based on the composition of ZL107, and by purifying, fine crystallization and transformation treatment during the alloy melting process to procure high quality alloy fusion, and use orthogonal test method to carry out a series of experiments to finally determine the best composition proportion, perform verification by gravity casting.When gravity molded with metal die, this new kind of high-performance cast alloy of aluminium, silicon and copper can achieve the as-cast mechanical performances to: tensile strength 223.4MPa, elongation rate 2.94%, Brinell Hardness HBS= 79.9%, in comparison with ZL107,27.6%, 27.8% , 11.9%HBS have been improved. To verify its practicality, we performed production test for this new type cast aluminium alloy. The result of production test shows that this cast aluminium alloy has better mechanical performance, formability and machinability and can completely meet the requirements for industrial use. this kind of alloy to be a new industrial alloy.