Optimized Design And Mechanical Properties Of ZL107 Alloy With High Property

Casting aluminium-silicon alloy is the most widely used aluminium alloy due to its good casting property. ZL107 alloy is one of the widely used alloys in industry since it has not only good casting characteristics but also good air seal property. As the mechanical properties of common ZL107 alloy, especially the ductility, is relatively worse and cannot meet the need of use of some important parts, the application of common ZL107 alloy is limited. So it has been a proposition of material researchers that how to improve the mechanical properties of common ZL107 alloy.This paper starts from the theory of improving the strength and toughness of aluminium alloy. A new kind of casting aluminium, silicon and copper alloy was obtained and the mechanical properties of the alloy are much better than the common ZL107 alloy by adding alloying elements and optimizing experiment method. The addition amount of Ti, Cd, Zn and Sb modification were optimized by orthogonal test. Different heat treatment processes were also taken into account. The effect of alloy elements, modification and heat treatment on the mechanical properties of the alloy was investigated and the optimal process parameters were obtained by the results of orthogonal test. The difference between Sb modification and Na modification and the effect of Ag has also been studied.Results show that the optimal chemical composition of the alloy is (wt%): ZL107, 0.116%Ti, 0.116%Cd, 0.043%Mg, 0.916%Zn . The better modification is salt Na (25%NaF+62%NaCl+13%KCl) which is 2.5% of the total of the melting alloy. The appropriate heat treatment process is 515°Cx5h quenching in 70°C water and 150℃x11h aging.The mechanical properties of the alloy treated by the above process can be improved greatly. That is, tensile strength σ_b=360.6MPa, elongation rate δ =3.65%, hardness HB=117. In comparison with common ZL107 alloy, the optimal aluminium alloy possesses much better mechanical properties and can be more widely used in industry and meet the needs for a lot applications.