Research Of Ultra Strength Aluminum-zinc Alloy

Ultra high strength aluminum alloy used for commercial aircraft, most of the parts arealuminum alloy. Because the quality of aluminum alloy has the advantage of light, easyprocessing and forming. Application of ultra high strength aluminum alloy is greatly, and thehot extrusion forming process is a kind of producing these hard aluminum alloy.Based on the experimental data and theoretical analysis, studied the specific pressure onthe microstructure and mechanical properties of squeeze casting of aluminum zinc alloy.Thestudy found that as pressure rise as the brinell hardness will increase, but when the pressurereaches250MPa, the brinell hardness declines. Under pressure,the crystal grains becomerefined, compared to the test piece with the metal mold gravity casting. Experimental study onthe squeeze casting aluminum zinc alloy after molding, again after T6heat treatment, itsmicrostructure and mechanical properties of alloy. Under this technology is also discussed,the change of aluminum zinc alloy microstructure and mechanical properties. Study foundthat the heat treatment parameters for squeeze casting Al-Zn alloy is solution-treated at480℃for12h and then aging at120℃for30h,which can enhance the property of alloy obviously.Test by squeeze casting molding process, aluminum zinc alloy extrusion into blankforming experiment, through the hot extrusion forming test profiles, hot extrusion formingprocess is studied on the mechanical behavior and microstructure of the alloy. Theexperiments showed that after hot extrusion, the tensile strength of the material and brinellhardness significantly improve; structure grain are more refinement and uniform after hotextrusion. Using the tensile under room temperature, brinell hardness and integratingmetallographic observation, this experimental study the T6, T73, deep cold on hot extrusionof squeeze casting Al-Zn alloy’s mechanical properties and microstructure. Tests showed thatthe sample after T6heat treatment, that the tensile strength up to678.97MPa and the yieldstrength can reach599.63MPa, elongation about of4.31%. After T73heat treatment, thesample losed13.8%of the tensile strength, but increased36.9%of the elongation.This study, though squeeze casting,hot extrusion,hot extrusion after pre-deformationand T6heat treatment methods, test the effect of different forming processes and T6heat treatment on the mechanical properties of Al-Zn-Mg-Cu alloy microstructure. After T6heattreatment, the mechanical properties of tensile strength up to687.08MPa, yield strength of657.91MPa, elongation of about6.14%.