Effects Of Erbium And Zirconium Micro Alloying On Microstructures And Properties Of Al-Si-Cu-Mg Casting Aluminum Alloy

Cast aluminium alloys have excellent casting property and mechanical properties, including Al-Si alloys, which have the most species and the most widely use in all kinds of cast aluminium alloys, Al-Si casting alloys are widely used in industry, aviation, transportation and so on. With the economic and social development, various industries need the higher requirements for the mechanical properties and corrosion resistance of aluminum alloys, for improving the properties of aluminum alloys, alloying is an important way, this article through adding Er and Zr to Al-Si-Cu-Mg casting aluminum alloys, in order to enhance the comprehensive properties of alloys.Based on the ZL106, different content of Er and Zr were added, making the alloys after melting finish three different kinds of heat treatment process:T5、T6、T7, joining compositely Er and Zr in different alloys, respectively, to explore the microstructure, mechanical properties and corrosion resistance of different alloys in as-cast、T5、T6、T7, so as to optimize the best composition of alloy, the results were as follows:According to the results of the cast alloys’mechanical property tests, in the as-cast, after joining Er and Zr the promotion of alloys’hardness, tensile strength, elongation after fracture was not obvious, the cast alloys’tensile fractures were mainly in the form of cleavage fracture, adding Er and Zr can refine microstructure to some degree, and form a small amount of strengthening phase. However, when the addition of Er to 0.35%, the mechanical properties of the alloys decreased obviously, and the Er elements had been added too much. Therefore, the addition of Er should be less than 0.35%.After the different composition of the alloys dealed with T5、T6、T7, the matrix structures of the alloys were obviously improved, tended to circular and small. After aging treatment, compounding to add Er and Zr can obviously improve the alloys of hardness, tensile strength and corrosion resistance. Through the analysis of the aging state alloys’ tensile fracture morphology, the alloys showed the characteristics of the ductile fracture, Er and Zr compounded to add, the alloys’characteristic of the ductile fracture was more obvious.According to the comparison of the various experimental datas, compounded to add Zr,Er than adding alone can improve the strength, hardness, plastic and corrosion resistance of cast aluminium alloys, and can optimize the organizations of the matrix alloys. when compounding to add 0.25%Zr+0.25%Er, the mechanical properties of the alloy achieved the best match, and its corrosion resistance was the best. In short, the alloy added 0.25%Zr+0.25%Er, which was the best alloy composition design for this paper.