Effect Of Si, Sb On Corrosion Resistance And Mechanical Properties Of Al Alloy

Traditional casting aluminum alloy has good corrosion resistance, heat resistance, low density and low thermal expansion coefficient advantages are widely used in various fields of national economy. However, in some of the higher strength requirements of the material conditions of corrosive environmental conditions, cast aluminum leaving their relatively low intensity applications are limited.In this paper, Al-6% Si casting silicon aluminum alloy as the research object, starting from two aspects modification and adjustment of alloying elements, without reducing the corrosion resistance of the alloy on the basis of improved strength silicon aluminum alloy. Experiment first Al-6% Si casting silicon aluminum alloy modification, select Sb as the modifier, adjust bad time, metamorphic temperature and the amount of the modifier and measure the sample hardness, corrosion resistance, observe the microstructure. Orthogonal experiment to determine the best treatment plan modification. Secondly, to further improve the strength, adjustment Sb, Si and trace elements Mn, Cr, Zn, Cu content and solid solution and aging treatment.By measuring the mechanical properties of hardness, wear resistance, corrosion resistance and other indicators, and electrochemical and microstructure analysis, conclusions showed that: For Al-6% Si alloy, when heat treatment temperature is 740 ℃, adding 0.2%Sb and do 10min modification,the best performance of Si Al alloy was obtained. After adding Sb alterative to Al-6%Si alloy, the coarse eutectic Si change from needle-like crystal to tiny evenly distributed short strip or granule, the dendrite crystal of α-Al is evenly distribute. When Sb content is 0.2, the grain size of the alloy is more refined, and the strength, abrasive resistance and corrosion resistance are the best; In the aluminum alloy W (Si)=2.4-3.2%, increase the Si content to (Si) W= 6%, the strength and hardness of the alloy rise, after solid solution and aging treatment, the corrosion resistance is also improved; After the solid solution aging treatment, the Sb content increases, the corrosion resistance decreases and the strength increases. After the Sb element modificate on Al-6%Si, this alloy’s hardness increase 18.7%, reach to 59.6HB.