The effect of zinc addition, strontium content and arc melting on the structural, mechanical and tribological properties of the 390a alloy

In this study, 390A, 390A+2%Zn and 390A+2%Zn+XSr alloys were produced by induction melting and arc melting under vacuum. The microstructure of the 390A alloy produced by induction melting was found to consist of α-Al, eutectic and primary Si, θ (CuAl2), β, δ, α-Al15 (FeMnCu)3Si2 phases. No new phase formed in the microstructure of the alloy when 2%Zn was added to the 390A alloy. When Sr was added to 390A+2% Zn alloy, it was observed that the dimensions of the phases in the microstructure were reduced or thin. It was also observed that Al2Si2Sr and μ(Al-Fe-Si-Mn) phases were formed when the strontium ratio exceeded 0.075%. When the 390A alloy is produced by arc melting method, it was observed that dimensions of α, θ and α-Al15(FeMnCu)3Si2 phases are slightly reduced, eutectic Si particles take a short and thick form. It was also observed that primary Si phase is distributed more homogeneously and the amount of it increased. In case of addition of 2%Zn to 390A alloy, β particles got thin and amount of the β phase increased. In the 390A+2%Zn+XSr alloys produced by arc melting method, the μ phase formed in 0.01%Sr content. The hardness of the 390A alloy increased with both the addition of 2% Zn and 0.075%Sr and arc melting method. The 390A alloy produced by induction melting showed lower tensile strength when it contained 2% Zn and 0.075%Sr. The 390A alloy produced by arc melting showed higher tensile strength than the 390A alloy produced by induction. Among the alloys produced by arc melting, the 390A alloys containing Zn and Sr exhibited lower tensile strength than the 390A alloy. Among the alloys produced by induction melting, 390A+2%Zn alloy exhibited the highest wear resistance while 390A alloy among the alloys produced by arc melting method exhibited the highest wear resistance.