Preparation, Microstructure And Properties Of 5182 Aluminum Alloy Modified With Al-Ti-B And Rare Earth Master Alloys

Based on the preparation of 5182 aluminum alloy in the national standard, the property at different levels of Mg, Fe and Mn in the aluminum alloy was studied by an orthogonal test. Meanwhile, the change in microstructure of the aluminum alloy was studied with the help of optic-microscope and SEM. Modification processes of Al-Ti-B and three kinds of RE including Ce, La and Y were used and compared with that of unmodification in order to further improve property and microstructure. Moreover, the melting and pouring processes were improved according to the experimental results.Results show that, Mg, one of the main solute elements in 5182 aluminum alloy, plays a strengthening effect by ways of solid solution and forming precipitated phase. Fe can increase flowability of aluminum alloy melts, decrease grain size and form harmful phase of FeAl3. Fe, Mn and Al can form (FeMn)Al6 phase to decrease FeAl3 phase and eliminate its unfavourable effect. Modifications of Al-Ti-B and RE elements can greatly decrease grain size of the alloy and improve mechanical property of the aluminum alloy. Concerning precipitated phase, the size of the precipitated phase decreases and appears diffuse as a result of the increase of the nucleation rate, which increases the dispersion effect in aluminum alloy. Concerning property, the tensile strength of 5182 aluminum alloy before modification is 235.8MPa. The tensile strength of the modified 5182 aluminum alloy, into which Al-Ti-B and Ce is 286.3MPa and 288.1MPa. The tensile strength of the modified 5182 aluminum alloy is higher than that before modification by 10%. Concerning the preparation of 5182 aluminum alloy, in the melting process of 5182 aluminum alloy, influence can be caused to the property of aluminum alloy by the adding method of the mid-alloy, the number of the mold gates and the temperature of the molds. By adopting Al-Mg and Al-Zn mid-alloy ultimate addition can decrease the wasting. The double mold gates, the temperature of the molds are controlled around 200℃, which has the least influence to the property of aluminum alloy.