7XXX aluminum alloy

Abstract

The invention relates to 7XXX aluminum alloy. The 7XXX aluminum alloy comprises the following components by weight percent: 6.6 to 7.6 percent of zinc, 1.25 to 1.80 percent of magnesium, 0.18 to 0.44 percent of copper, less than or equal to 0.06 percent of silicon, less than or equal to 0.16 percent of iron, , less than or equal to 0.03 percent of manganese, less than or equal to 0.03 percent of chromium, less than or equal to 0.02 percent of germanium, less than or equal to 0.02 percent of vanadium, less than or equal to 0.03 percent of titanium, less than or equal to 0.02 percent of zirconium, and less than or equal to 0.03 percent of total weight of manganese and chromium, less than or equal to 0.03 percent of each rest impurity element, less than or equal to 0.10 percent of total weight of rest impurity elements, and the balance of aluminum. On the basis of experiment, the material strength is improved by re-designing the mass fraction and a ratio of Zn to Mg; by re-designing the mass fraction of Cu, the alloy has excellent corrosion resistance, and the oxidation different color problem of silver white can be solved. By strictly controlling the weight percent of the impurity elements such as Mn and Cr, the crystal grains of the alloy material are uniform. Compared with the existing disclosed Al-Zn alloy system, the alloy has better comprehensive performance, and an oxidized membrane formed by oxidizing the material by virtue of anode is more delicate and beautiful.

Description

technical field [0001] The invention relates to an alloy, in particular to a 7XXX series aluminum alloy. Background technique [0002] Aluminum alloys are made by adding some alloying elements to pure aluminum, such as Al-Mn alloys developed by adding manganese elements to pure aluminum, Al-Cu alloys developed by adding copper elements to pure aluminum, and copper added to pure aluminum at the same time. Al-Cu-Mg series hard aluminum alloys were developed with magnesium elements, and Al-Zn-Mg-Cu series superhard aluminum alloys were developed by adding zinc, magnesium, and copper elements to pure aluminum at the same time. Compared with other materials, aluminum alloy has excellent comprehensive properties: it has low density, superior corrosion resistance, good plasticity and processing performance, strong electrical and thermal conductivity, low temperature brittleness resistance, good surface treatment performance, non-magnetic, acid resistance, radiation resistance adva...

AI Technical Summary

Problems solved by technology

[0004] Although the strength of 7XXX series aluminum alloys is superior to that of 6XXX series aluminum alloys, the tensile strength and yield strength of some alloys can reach more than 400Mpa, but the tensile strength and yield strength of 7XXX series aluminum alloys both reach more than 400Mpa, after anodic oxidation, the surface The quality is not as fine as 6XXX series deformed aluminum alloys, there are surface defects such as stripes and different colors, and the decorative aesthetics are low

In addition, the oxide film of the 7XXX series deformed aluminum alloy anodic oxidation process is unstable, and problems such as stress corrosion and stripping are prone to occur. Therefore, there are few implementation cases of 7XXX series aluminum alloys applied to exterior decoration materials.

[0005] In addition, due to the high-strength 7XXX series aluminum alloy, it is difficult to form. Taking the production of extruded plates as an example, reverse extrusion is generally used, or forward extrusion is used to produce simple cross-section profiles with an extrusion ratio ≤ 30. The 7XXX series aluminum alloy profiles with large pressure ratio are difficult to extrude and the production efficiency is low, so the difficulty of forming also limits the application of 7XXX series aluminum alloys in the field of electronic product casings with high decorative requirements

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