CN105112747B - A kind of 7XXX aluminium alloys - Google Patents

Abstract

A kind of 7XXX aluminium alloys, the content (weight percent) of each ingredient of the aluminium alloy are：Zn content is 6.6%~7.6%, content of magnesium is 1.25%~1.80%, and copper content is 0.18%~0.44%, silicone content≤0.06%, iron content≤0.16%, manganese content≤0.03%, chromium content≤0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, zirconium content≤0.02%, manganese add chromium summation≤0.03%；Single content≤0.03% of remaining impurity element, remaining impurity element summation≤0.10%, surplus is aluminium.In experimental basis, by redesigning the mass fraction and ratio of zinc Zn, magnesium Mg elements, the intensity of material is improved；By the mass fraction for redesigning copper Cu elements so that alloy solves the problems, such as that silvery white oxidation is heterochromatic while having both excellent corrosion resistance.By the mass percent for strictly controlling manganese Mn, chromium Cr impurity elements so that the crystal grain of alloy material is uniform.Compared with existing disclosed Al Zn alloy systems, which has more excellent comprehensive performance, and the oxide-film that material obtains after anodic oxidation is more fine and smooth beautiful.

Description

A kind of 7XXX aluminium alloys

Technical field

The present invention relates to a kind of alloy more particularly to a kind of 7XXX series alloys.

Background technology

Aluminium alloy is that fine aluminium is added in made of alloying elements, and the Al-Mn that manganese element is developed is added such as in fine aluminium Alloy adds copper in fine aluminium and develops made of Al-Cu alloy, in fine aluminium while adds copper and magnesium elements develop Al-Cu- Mg systems duralumin, hard alumin ium alloy, adding zinc, magnesium, copper develops Al-Zn-Mg-Cu 7 series extra super duralumin alloys etc. simultaneously in fine aluminium.It compares There is excellent comprehensive performance compared with other materials aluminium alloy：It is with density is small, corrosion resistance is superior, plasticity and processing performance are good Good, the advantages that electrical and thermal conductivity is strong, low temperature resistant brittleness, surface treatment properties are good, nonmagnetic, acid resistance, radiation resistance.In power Aspect of performance is learned, the selectable range of aluminum alloy materials is relatively broad.The conventional mechanical property of aluminium and aluminium alloy is with alloy species With the difference of state, tensile strength sigma b can change between 50~800MPa, and yield strength σ 0.2 can be in 10~700MPa Between change, elongation percentage δ can change between 2%~50%.More than having the advantages that because of aluminium alloy, aluminum alloy materials are led in industry Domain is widely used in following three aspects：First, as primary structure member；Second is that as materials such as door, window, pipe, lid, shells；Third, make For decoration and heat-insulating material.Aluminium alloy, can be by artificial also with excellent surface treatment properties except having more than characteristic The modes such as anodic oxidation, spraying obtain shell of the preferable surface effect as ornament materials.

With the development and popularization of material science, wrought aluminium alloy is in phone housing, panel computer shell, desktop computer machine The application in the electronic product casings fields such as case, liquid crystal display shell, smart television shell is more and more extensive.With phone housing material Exemplified by material, wrought aluminium alloy substitutes other materials as phone housing, it has also become the popular tendency in industry, compared to more other materials Material, wrought aluminium alloy have the following advantages：Material is light, intensity is high, conductance thermal conductivity is good, easy processing, incrustation performance are excellent Good, the most widely used wrought aluminium alloy in mobile phone electronic field is 6XXX systems alloy at present, as market and application field are to material Expect increasingly higher demands, traditional 6XXX wrought aluminium alloys have been difficult to the requirement for meeting high-end product in terms of intensity, especially It bends in resistance to deformation, and in terms of the indexs such as anti-drop deformation, 6XXX systems wrought aluminium alloy is poor compared with 7XXX wrought aluminium alloys Away from larger by taking phone housing product as an example, according to fall-down test, statistics indicate that, tensile strength, the yield strength of material reach During more than 400Mpa, the non-deformability of fall-down test is in comparatively ideal state.Tensile strength, yield strength are below The disqualification rate of anti-drop experiment is relatively high in the case of 400Mpa.

Although 7XXX line aluminium alloys are better than 6XXX line aluminium alloys, alloy part tensile strength and yield strength energy in intensity Enough reach more than 400Mpa, but tensile strength, yield strength reach the 7XXX line aluminium alloys of more than 400Mpa, through anodic oxygen Change rear surface quality not as good as 6XXX systems wrought aluminium alloy exquisiteness, there are the surface defects such as striped, heterochromatic, beautiful decoration degree is low.And And the oxide-film of 7XXX systems wrought aluminium alloy anodic oxidation stroke is unstable, the problems such as being susceptible to stress corrosion, demoulding, therefore The case study on implementation that 7XXX line aluminium alloys are applied to decorative appearance material is less.

Further, since high intensity 7XXX line aluminium alloys, difficult forming, exemplified by producing extrusion plate, generally using Reverse extrusion produces or the simple section section bar with forward extrusion production extrusion ratio≤30, the big 7XXX systems aluminium of production extrusion ratio It is high in cosmetic requirement that alloy profile extruding difficulty, low production efficiency, therefore difficult forming also limit 7XXX line aluminium alloys The application in electronic product casing field.

The content of the invention

For overcome the deficiencies in the prior art, the invention discloses one kind to have excellent formability energy, and extruding efficiency is high, resists Tensile strength reaches more than 400Mpa, yield strength reaches more than 400MPa, has both the fine and smooth beautiful novel aluminum of anode oxide film and closes Gold.

The present invention makes the tensile strength of alloy, yield strength steady by the proportioning of careful design magnesium elements and Zn-ef ficiency Surely more than 400Mpa is reached；By limit the zr element in alloy, manganese element, chromium content, improve these three elements The adverse effect inhibited when squeezing to crystallization so that material structure is uniform, improves the anodic oxidation film quality of material；Pass through Cu elements are added in alloy, improves the stress corrosion resistant ability of alloy, promote the grain boundary corrosion resistance of alloy；Pass through Cu elements Careful design, the anodic oxidation chemical polishing time can be shortened, avoid long chemical polishing time Surface Quality not Profit influences, and improves the sophistication of anode oxide film.

The invention discloses a kind of 7XXX aluminium alloys, the content (weight percent) of the aluminium alloy each element is：Zinc contains It measures as 6.6%~7.6%, content of magnesium is 1.25%~1.80%, and copper content is 0.18%~0.44%, silicone content≤ 0.06%, iron content≤0.16%, manganese content≤0.03%, chromium content≤0.03%, gallium content≤0.02%, content of vanadium≤ 0.02%, Ti content≤0.03%, zirconium content≤0.02%, manganese adds chromium summation≤0.03%；The single content of remaining impurity element ≤ 0.03%, remaining impurity element summation≤0.10%, surplus is aluminium.

Further, the composition of each component is respectively by weight percentage：Zinc：6.8%~7.0%；Magnesium：1.4%~ 1.6%；Copper：0.20%~0.24%；Surplus is aluminium.

Further, iron is also contained in the aluminium alloy, the highest weight percent of iron is 0.12%

Further, silicon is also contained in the aluminium alloy, the highest weight percent of silicon is 0.06%.

Further, it is up to the impurity generated under 0.10% manufacturing condition also comprising weight percent is amounted to, each The weight percent of impurity is up to 0.03%.

Further, in the impurity containing manganese or the composition of chromium or manganese and chromium, the weight percent of the manganese and chromium It is up to 0.03% altogether.

Further, gallium is contained in the impurity, the highest weight percent of gallium is 0.02%.

Further, vanadium is contained in the impurity, the highest weight percent of vanadium is 0.02%.

Further, zirconium is contained in the impurity, the highest weight percent of zirconium is 0.02%.

A kind of 7XXX aluminium alloys, the content (weight percent) of the aluminium alloy each element are：Zn content for 6.6%~ 7.6%, content of magnesium is 1.25%~1.80%, and copper content is 0.18%~0.44%, silicone content≤0.06%, iron content≤ 0.16%, manganese content≤0.03%, chromium content≤0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤ 0.03%, zirconium content≤0.02%, manganese adds chromium summation≤0.03%；Single content≤0.03% of remaining impurity element, remaining is miscellaneous Prime element summation≤0.10%, surplus are aluminium；The aluminium alloy is used to manufacture the structural member of electronic product and can be carried out for manufacturing The shell decorative product of pole oxidized surface processing..

The 7XXX aluminium alloys of the present invention improve material by redesigning the mass fraction and ratio of zinc Zn, magnesium Mg elements The intensity of material；By the mass fraction for redesigning copper Cu elements so that alloy solves while having both excellent corrosion resistance Silvery white aoxidizes heterochromatic problem.By the mass percent for strictly controlling manganese Mn, chromium Cr impurity elements so that the crystal grain of alloy material Uniformly.Compared with existing disclosed Al-Zn alloy systems, which has more excellent comprehensive performance, and material is through anodic oxygen The oxide-film obtained after change is more fine and smooth beautiful.

In order to better understand and implement, the invention will now be described in detail with reference to the accompanying drawings.

Description of the drawings

Fig. 1 is the aluminum alloy extrusion section bar flow process chart of all embodiments and comparative example in the present invention.

Specific embodiment

Embodiment one

The invention discloses a kind of 7XXX series alloys, which is 7A07 aluminium alloys.The aluminium of the present invention closes The content (weight percent) of each element is in gold：Zn content is 6.60%~7.60%, and content of magnesium is 1.25%~1.80%, Copper content is 0.18%~0.44%, silicone content≤0.06%, iron content≤0.16%, manganese content≤0.03%, chromium content≤ 0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, zirconium content≤0.02%, manganese adds chromium summation ≤ 0.03%；Single content≤0.03% of remaining impurity element, remaining impurity content summation≤0.10%, surplus is aluminium.

Using above-mentioned aluminium alloy composition, extrudate is produced.Shape extrusion order is cast as round ingot casting for A1 meltings → A2 Preheating → A5 extrusion formings → A6 on-line solutions → A7 aging strengthening models → A8 is fixed before → A3 homogenizing annealings → A4 ingot castings squeeze The artificial anodized surface processing of ruler sawing → A9.By the aluminium alloy extrusions fabricated above, the extrudate tension is strong Degree reaches 415~455Mpa, yield strength reaches 405~425Mpa, elongation percentage reaches more than 12%；The extrudate makees intergranular Corrosion test maximum corrosion depth is less than 0.03mm, and intercrystalline corrosion rank is less than 2 grades；The grain structure of the extrudate is complete Equi-axed crystal is recrystallized, crystal grain distribution is uniform, and average grain diameter is 85 μm；The extrudate is through mechanical grinding, at 85 DEG C Chemical polishing is carried out under phosphoric acid environment, glossiness reached the 35Gu required times for 20~40 seconds；The extrudate is through remarkable After work anodic oxidation, oxide-film is fine and smooth uniformly, and surface quality is beautiful, and not colour cast when making silvery white anodic oxidation.

The aluminium alloy is used to manufacture the structural member of electronic product and for manufacturing the shell that can carry out pole oxidized surface processing Decorative product.

The performance parameter of alloy described in the present embodiment see the table below：

Hereinafter, for the content of each composition is carried out numerical definiteness the reasons why, is illustrated:

Mg, Zn element are the main intensified elements in alloy, and in 7 line aluminium alloys, 7 line aluminium alloys are with Mg, Zn content Raising, intensity and hardness improve but the stress corrosion resistant of material and the tough sexuality of Resisting fractre reduce.Mg, Zn element are in 7XXX The existence form of line aluminium alloy is existed with compound form, and room temperature texture is mainly η MgZn₂Phase and TAl₂Mg₃Zn₃Phase.η phases Solubility at 470 DEG C in aluminium is 28%, and there was only 4% at room temperature, therefore η phases have very high quenching strengthening and ageing strengthening Fruit；T-phase is at 489 DEG C, and the solubility in aluminium is 17%, and with the reduction of temperature, solubility is reduced rapidly, and room temperature is only 1.0%, therefore T-phase has very high quenching strengthening and ageing strengthening.According to above analysis, therefore, alloy of the present invention is by magnesium elements Weight percent is defined to more than 1.25%, less than 1.80%, the weight percent of Zn content is defined to more than 6.6%, Less than 7.6%.

Fe, Si element are harmful elements in 7 series alloys, they are essentially from raw material and melting, casting process The middle instrument used and equipment.Fe and Si is in 7 line aluminium alloys mainly with FeAl₃Exist with free Si forms, this there are shapes State significantly reduces the fracture toughness of material, FeAl₃It is distributed in alloy matrix aluminum, because corrosion potential is inconsistent with aluminum substrate, meeting The homogeneity of oxide-film is disturbed, declining the quality of anode oxide film influences aesthetics, and therefore, alloy of the present invention is by Fe elements Content (weight percent) is limited within 0.16%, the content of Si elements is limited within 0.06%.

When Cu elements are in Al-Zn-Mg alloy, matrix current potential when on the one hand can improve alloy anode oxidation is reduced The potential difference of matrix and Grain Boundary Precipitates and improve the corrosion resistance of alloy, on the other hand can have by Precipitation CuAl₂Chemical composition composition, with the θ ' of half symbiosis and epibiosis of matrix phase and supplementary function is played to the reinforcing of alloy, Cu elements add Although adding the intensity for improving material to a certain extent and stress corrosion resistant and anti-strip corrosive power, by a large amount of examinations The increase of Cu element weight percents in showing in 7XXX systems Al-Zn-Mg-Cu alloy with alloy is tested, alloy is in anode It is present with heterochromatic phenomenon during oxidation, actual oxidation effectiveness is partially golden yellow, the degree of colour cast and the weight of Cu elements when silvery white aoxidizes Percentage direct proportionality is measured, research also shows the homogeneous of the addition meeting severe jamming intra-die corrosion of excessive Cu elements Property so that material is processed the oxide-film sophistication to be formed by anodic oxidation and is declined, and reduces beautiful decoration.Therefore, it is of the invention The content (weight percent) of Cu elements is limited in more than 0.18%, less than 0.44%.

A small amount of Mn elements have significant impact in Al-Zn-Mg alloy to the recrystallization of alloy, especially in extrusion process Stage can prevent dislocation and crystal boundary migration, improve the recrystallization temperature of material, so as to influence the structural homogenity shadow of extrudate The surface quality after material anodic oxidation is rung, therefore, the content (weight percent) of Mn elements is limited in by alloy of the present invention Less than 0.03%.

Influence of a small amount of Cr elements to alloy in Al-Zn-Mg alloy is similar with Mn, is not elaborated, therefore, this The content (weight percent) of Cr elements is limited in less than 0.03% by invention alloy.

Since the inhibiting mechanism that Mn, Cr recrystallize Al-Zn-Mg alloy is similar, alloy of the present invention by Mn elements and Content (weight percent) summation of Cr elements is limited within 0.03%.

Zr elements can improve the stress corrosion resistant ability of alloy in Al-Zn-Mg alloy, but Zr elements can be notable Raising material recrystallization temperature, make material grain structure after extrusion forming uneven, and can shape during Zr element excess Into coarse ZrAl₃, the above characteristic of Zr elements eventually influences the quality of extrudate anode oxide film, adds anodic oxidation The content (weight percent) of Zr elements is defined within 0.02% by work rear surface deterioration, therefore, the present invention.

Ti elements mainly play crystal grain thinning in Al-Zn-Mg alloy in casting link, but when Ti excess, The surface of section bar can be hindered as Hard Inclusion card so that surface quality deteriorates, and experiments have shown that the thin of crystal grain after Ti content saturations Change effect to help without notable, therefore, Ti contents (weight percent) are limited within 0.03% by the present invention meets casting refinement Effect has no effect on the surface quality of material.

7A07 alloys are in addition to aforementioned elements, and surplus is made of aluminium and inevitable impurity, as inevitable Impurity element, such as think there are the elements such as Ga, V, but if the respective content of these impurity elements within 0.03%, The characteristic of alloy of the present invention is not interfered with.

Embodiment two

In the present embodiment, the content (weight percent) of each element of 7XXX aluminium alloys is：Zn content is 6.6%, and magnesium contains It measures as 1.25%, copper content 0.18%, silicone content≤0.06%, iron content≤0.16%, manganese content≤0.03%, chromium content ≤ 0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, zirconium content≤0.02%, manganese adds chromium total With≤0.03%；Single content≤0.03% of remaining impurity element, remaining impurity content summation≤0.10%, surplus are Aluminium.

Using above-mentioned aluminium alloy composition, extrudate is produced.Shape extrusion order is cast as round ingot casting for A1 meltings → A2 Preheating → A5 extrusion formings → A6 on-line solutions → A7 aging strengthening models → A8 is fixed before → A3 homogenizing annealings → A4 ingot castings squeeze The artificial anodized surface processing of ruler sawing → A9.By the aluminium alloy extrusions fabricated above, the extrudate tension is strong Degree reaches 415Mpa, yield strength reaches 405Mpa, elongation percentage reaches 12%；It is maximum rotten that the extrudate makees intercrystalline corrosion test Depth is lost between 0.01~0.03mm, and intercrystalline corrosion rank is 2 grades；The grain structure of the extrudate is perfect recrystallization etc. Axialite grain, crystal grain distribution is uniform, and average grain diameter is 85 μm；The extrudate is through mechanical grinding, in 85 DEG C of phosphoric acid environment Lower carry out chemical polishing, glossiness reached the 35Gu required times for 40 seconds；The extrudate by artificial anodic oxidation it Afterwards, oxide-film is fine and smooth uniformly, and surface quality is beautiful, and not colour cast when making silvery white anodic oxidation.

Embodiment three

In the present embodiment, the content (weight percent) of each element of 7XXX aluminium alloys is：Zn content is 7.00%, and magnesium contains It measures as 1.40%, copper content 0.30%, silicone content≤0.06%, iron content≤0.16%, manganese content≤0.03%, chromium content ≤ 0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, zirconium content≤0.02%, manganese adds chromium total With≤0.03%；Single content≤0.03% of remaining impurity element, remaining impurity content summation≤0.10%, surplus are Aluminium.

Using above-mentioned aluminium alloy composition, extrudate is produced.Shape extrusion order is cast as round ingot casting for A1 meltings → A2 Preheating → A5 extrusion formings → A6 on-line solutions → A7 aging strengthening models → A8 is fixed before → A3 homogenizing annealings → A4 ingot castings squeeze The artificial anodized surface processing of ruler sawing → A9.By the aluminium alloy extrusions fabricated above, the extrudate tension is strong Degree reaches 425Mpa, yield strength reaches 410Mpa, elongation percentage reaches 12%；It is maximum rotten that the extrudate makees intercrystalline corrosion test Depth is lost between 0.01~0.03mm, and intercrystalline corrosion rank is 2 grades；The grain structure of the extrudate is perfect recrystallization etc. Axialite grain, crystal grain distribution is uniform, and average grain diameter is 85 μm；The extrudate is through mechanical grinding, in 85 DEG C of phosphoric acid environment Lower carry out chemical polishing, glossiness reached the 35Gu required times for 30 seconds；The extrudate by artificial anodic oxidation it Afterwards, oxide-film is fine and smooth uniformly, and surface quality is beautiful, and not colour cast when making silvery white anodic oxidation.

Example IV

The content (weight percent) of 7XXX aluminium alloys each element of the present invention is：Zn content is 7.60%, and content of magnesium is 1.80%, copper content 0.44%, silicone content≤0.06%, iron content≤0.16%, manganese content≤0.03%, chromium content≤ 0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, zirconium content≤0.02%, manganese adds chromium summation ≤ 0.03%；Single content≤0.03% of remaining impurity element, remaining impurity content summation≤0.10%, surplus is aluminium.

Using above-mentioned aluminium alloy composition, extrudate is produced.Shape extrusion order is cast as round ingot casting for A1 meltings → A2 Preheating → A5 extrusion formings → A6 on-line solutions → A7 aging strengthening models → A8 is fixed before → A3 homogenizing annealings → A4 ingot castings squeeze The artificial anodized surface processing of ruler sawing → A9.By the aluminium alloy extrusions fabricated above, the extrudate tension is strong Degree reaches 455Mpa, yield strength reaches 425Mpa, elongation percentage reaches 12%；It is maximum rotten that the extrudate makees intercrystalline corrosion test It loses depth and is less than 0.01mm, intercrystalline corrosion rank is 1 grade；The grain structure of the extrudate is perfect recrystallization equi-axed crystal, Crystal grain distribution is uniform, and average grain diameter is 85 μm；The extrudate is changed through mechanical grinding under 85 DEG C of phosphoric acid environment Optical polishing, glossiness reached the 35Gu required times for 20 seconds；The extrudate passes through after artificial anodic oxidation, oxide-film Fine and smooth uniformly surface quality is beautiful, and not colour cast when making silvery white anodic oxidation.

Comparative example 1

The content (weight percent) of each element of this comparative example aluminium alloy is：Zn content is 6.60%~7.60%, magnesium Content is 1.25%~1.80%, copper content 0.02%, silicone content≤0.06%, iron content≤0.16%, manganese content≤ 0.03%, chromium content≤0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, zirconium content≤ 0.02%, manganese adds chromium content summation≤0.03%；Single content≤0.03% of remaining impurity element, remaining impurity content are total With≤0.10%, surplus is aluminium.

Such as the aluminium alloy in embodiment 1 to 4, difference lies in copper in alloying element between comparative example 1 and embodiment 1 to 4 Content, using above-mentioned aluminium alloy composition, produces extrudate far below 1 to 4 lower limit value of example is applied.Shape extrusion order melts for A1 Refining → A2 be cast as preheating → A5 extrusion formings → A6 on-line solutions before round ingot casting → A3 homogenizing annealings → A4 ingot castings squeeze → The artificial anodized surface processing of A7 aging strengthening models → A8 scales sawing → A9.It is maximum that the extrudate makees intercrystalline corrosion test For corrosion depth between 0.10~0.30mm, intercrystalline corrosion rank is 4 grades；Cause comparative example alloy corrosion among crystalline grains low Main cause is non-field Cu elements in alloy, material anti intercrystalline corrosion energy force difference, therefore, it is necessary to limit the copper of invention alloy Content (weight percent) lower limiting value is 0.18%.

Comparative example 2

The content (weight percent) of each element of this comparative example aluminium alloy is：Zn content is 6.60%~7.60%, magnesium Content is 1.25%~1.80%, copper content 0.55%, silicone content≤0.06%, iron content≤0.16%, manganese content≤ 0.03%, chromium content≤0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, zirconium content≤ 0.02%, manganese adds chromium summation≤0.03%；Single content≤0.03% of remaining impurity element, remaining impurity content summation≤ 0.10%, surplus is aluminium.

Such as the aluminium alloy in embodiment 1 to 4, difference lies in copper in alloying element between comparative example 2 and embodiment 1 to 4 Content, using above-mentioned aluminium alloy composition, produces extrudate higher than upper limit value in example 1 to 4 is applied.Shape extrusion order is A1 meltings → A2 is cast as preheating → A5 extrusion formings → A6 on-line solutions → A7 before round ingot casting → A3 homogenizing annealings → A4 ingot castings squeeze The artificial anodized surface processing of aging strengthening model → A8 scales sawing → A9.The extrudate by artificial anodic oxidation it Afterwards, actual effect is faint yellow after making silvery white dyeing processing, occurs apparent colour cast phenomenon, and anode oxide film it is uneven go out Existing strip flaw.Comparative example alloy is caused the reason for heterochromatic anode and anode surface deterioration occur, is the Cu members in alloy Plain excessive addition, Cu elements corrosion potential in anodic oxidation is low and aluminum substrate, after compound containing Cu reaches a certain concentration, meeting The uniformity of oxide-film is disturbed, etch striation defect occurs and causes anode oxide film deterioration, and Cu elements are combined with Al The CuAl of formation₂It can be reacted with coloring agent and generate colour cast phenomenon.Therefore, it is necessary to limit the copper content (weight hundred of invention alloy Point ratio) upper limit value be 0.44%.

Comparative example 3

The content (weight percent) of each element of this comparative example aluminium alloy is：Zn content is 6.60%~7.60%, magnesium Content is 1.25%~1.80%, and copper content is 0.18%~0.44%, silicone content≤0.06%, iron content 0.30%, manganese Content≤0.03%, chromium content≤0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, zirconium contain Amount≤0.02%, manganese adds chromium content summation≤0.03%；Single content≤0.03% of remaining impurity element, remaining impurity element contain Summation≤0.10% is measured, surplus is aluminium.

Such as the aluminium alloy in embodiment 1 to 4, difference lies in iron in alloying element between comparative example 3 and embodiment 1 to 4 Content, using above-mentioned aluminium alloy composition, produces extrudate higher than limits value in example 1 to 4 is applied.Shape extrusion order is A1 meltings → A2 is cast as preheating → A5 extrusion formings → A6 on-line solutions → A7 before round ingot casting → A3 homogenizing annealings → A4 ingot castings squeeze The artificial anodized surface processing of aging strengthening model → A8 scales sawing → A9.The extrudate by artificial anodic oxidation it Afterwards, there is strip flaw in anode film, and surface quality is poor.Anode oxide film is caused the reason for strip flaw occur, is Fe in alloy Element is excessive, and excessive Fe elements combine to form coarse FeAl3 with Al, and FeAl3 is distributed in alloy matrix aluminum, edge during extruding It the direction of extrusion to crush and be linearly distributed, because FeAl3 corrosion potentials are inconsistent with aluminum substrate, the homogeneity of oxide-film is disturbed to produce Green anode oxide-film strip flaw.Therefore, it is necessary to the iron content (weight percent) of invention alloy is limited within 0.16%.

Comparative example 4

The content (weight percent) of each element of this comparative example aluminium alloy is：Zn content is 6.60%~7.60%, magnesium Content is 1.25%~1.80%, and copper content is 0.18%~0.44%, silicone content≤0.06%, iron content≤0.16%, manganese Content≤0.03%, chromium content≤0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, zirconium contain It measures as 0.10%, manganese adds chromium content summation≤0.03%；Single content≤0.03% of remaining impurity element, remaining impurity element contain Summation≤0.10% is measured, surplus is aluminium.

Such as the aluminium alloy in embodiment 1 to 4, difference lies in zirconiums in alloying element between comparative example 4 and embodiment 1 to 4 Content, using above-mentioned aluminium alloy composition, produces extrudate higher than limits value in example 1 to 4 is applied.Shape extrusion order is A1 meltings → A2 is cast as preheating → A5 extrusion formings → A6 on-line solutions → A7 before round ingot casting → A3 homogenizing annealings → A4 ingot castings squeeze The artificial anodized surface processing of aging strengthening model → A8 scales sawing → A9.The grain structure of the extrudate is not exclusively again Crystalline structure, grain size is extremely uneven, and grain shape is irregular, and average grain diameter is 15 μm；The extrudate is through artificial After anodic oxidation, there is color spot and strip flaw in oxide-film, and anodic anodization film quality is poor.The reason for causing the problem It is that the zr element content (weight percent) in alloy is excessive, and zr element is in extrusion process, it is suppressed that extrudate is tied again It is brilliant so that recrystallization temperature improves, and recrystallization temperature is not achieved in actual extrusion temperature so that the tissue part of extrudate is Subgrain part is recrystal grain, and the inhomogeneities of grain structure finally affects the uniformity of anode oxide film so that anode The deterioration of oxide-film.Therefore, it is necessary to the zirconium content (weight percent) of invention alloy is limited within 0.02%.

Comparative example 5

The content (weight percent) of each element of this comparative example aluminium alloy is：Zn content is 6.60%~7.60%, magnesium Content is 1.25%~1.80%, and copper content is 0.18%~0.44%, silicone content≤0.06%, iron content≤0.16%, manganese Content is 0.05%, chromium content≤0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, and zirconium contains Amount≤0.02%, manganese adds chromium content summation ＞ 0.03%；Single content≤0.03% of remaining impurity element, remaining impurity element contain Summation≤0.10% is measured, surplus is aluminium.

Such as the aluminium alloy in embodiment 1 to 4, difference lies in manganese in alloying element between comparative example 5 and embodiment 1 to 4 Content, using above-mentioned aluminium alloy composition, produces extrudate higher than limits value in example 1 to 4 is applied.Shape extrusion order is A1 meltings → A2 is cast as preheating → A5 extrusion formings → A6 on-line solutions → A7 before round ingot casting → A3 homogenizing annealings → A4 ingot castings squeeze The artificial anodized surface processing of aging strengthening model → A8 scales sawing → A9.The grain structure of the extrudate is not exclusively again Crystalline structure, grain size is extremely uneven, and grain shape is irregular, and average grain diameter is 25 μm；The extrudate is through artificial After anodic oxidation, there is color spot and strip flaw in oxide-film, and anodic anodization film quality is poor.The reason for causing the problem It is that the manganese element content (weight percent) in alloy is excessive, and manganese element is in extrusion process, it is suppressed that extrudate is tied again It is brilliant so that recrystallization temperature improves, and recrystallization temperature is not achieved in actual extrusion temperature so that the tissue part of extrudate is Subgrain part is recrystal grain, and the inhomogeneities of grain structure finally affects the uniformity of anode oxide film so that anode The deterioration of oxide-film.Therefore, it is necessary to the manganese content (weight percent) of invention alloy is limited within 0.03%.

Comparative example 6

The content (weight percent) of each element of this comparative example aluminium alloy is：Zn content is 6.60%~7.60%, magnesium Content is 1.25%~1.80%, and copper content is 0.18%~0.44%, silicone content≤0.06%, iron content≤0.16%, manganese Content≤0.03%, chromium content 0.05%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, zirconium contain Amount≤0.02%, manganese adds chromium content summation ＞ 0.03%；Single content≤0.03% of remaining impurity element, remaining impurity element contain Summation≤0.10% is measured, surplus is aluminium.

Such as the aluminium alloy in embodiment 1 to 4, difference lies in chromium in alloying element between comparative example 6 and embodiment 1 to 4 Content, using above-mentioned aluminium alloy composition, produces extrudate higher than limits value in example 1 to 4 is applied.Shape extrusion order is A1 meltings → A2 is cast as preheating → A5 extrusion formings → A6 on-line solutions → A7 before round ingot casting → A3 homogenizing annealings → A4 ingot castings squeeze The artificial anodized surface processing of aging strengthening model → A8 scales sawing → A9.The grain structure of the extrudate is not exclusively again Crystalline structure, grain size is extremely uneven, and grain shape is irregular, and average grain diameter is 20 μm；The extrudate is through artificial After anodic oxidation, there is color spot and strip flaw in oxide-film, and anodic anodization film quality is poor.The reason for causing the problem It is that the chromium content (weight percent) in alloy is excessive, and chromium is in extrusion process, it is suppressed that extrudate is tied again It is brilliant so that recrystallization temperature improves, and recrystallization temperature is not achieved in actual extrusion temperature so that the tissue part of extrudate is Subgrain part is recrystal grain, and the inhomogeneities of grain structure finally affects the uniformity of anode oxide film so that anode The deterioration of oxide-film.Therefore, it is necessary to the chromium content (weight percent) of invention alloy is limited within 0.03%.

Comparative example 7

The content (weight percent) of each element of this comparative example aluminium alloy is：Zn content is 6.60%~7.60%, magnesium Content is 1.25%~1.80%, and copper content is 0.18%~0.44%, silicone content≤0.06%, iron content≤0.16%, manganese Content is 0.03%, chromium content 0.03%, gallium content≤0.02%, content of vanadium≤0.02%, Ti content≤0.03%, and zirconium contains Amount≤0.02%, manganese add chromium content summation to be 0.06%；Single content≤0.03% of remaining impurity element, remaining impurity element contain Summation≤0.10% is measured, surplus is aluminium.

Such as the aluminium alloy in embodiment 1 to 4, difference lies in manganese in alloying element between comparative example 6 and embodiment 1 to 4 Content with chromium is within the limits value in applying example 1 to 4, but the sum of content of manganese and chromium (weight percent) is more than Apply the limits value of example 1 to 4.Using above-mentioned aluminium alloy composition, extrudate is produced.Shape extrusion order is A1 meltings → A2 castings Preheating → A5 extrusion formings → A6 on-line solutions → A7 timeliness is hot before causing round ingot casting → A3 homogenizing annealings → A4 ingot castings extruding The artificial anodized surface processing of processing → A8 scales sawing → A9.The grain structure of the extrudate is incomplete recrystallized group It knits, grain size is extremely uneven, and grain shape is irregular, and average grain diameter is 22 μm；The extrudate is through artificial anodic oxygen After change, there is color spot and strip flaw in oxide-film, and anodic anodization film quality is poor.The reason for causing the problem is alloy The sum of interior manganese element and chromium content (weight percent) are excessive, and manganese and chromium are in extrusion process, it is suppressed that squeeze The recrystallization of section bar so that recrystallization temperature improves, and recrystallization temperature is not achieved in actual extrusion temperature so that extrudate Tissue part is that subgrain part is recrystal grain, and the inhomogeneities of grain structure finally affects the uniform of anode oxide film Property so that the deterioration of anode oxide film.Therefore, it is necessary to limit invention alloy manganese and chromium content (weight percent) it With within 0.03%.

Referring to Fig. 1, each process is described as follows in Fig. 1：

A1 is melting process：The purpose of melting is to obtain the alloy that composition meets target call；

A2 is casting process：The mode used is made for Vertical Heat direct casting, and the extrusion billet of definite shape is obtained by casting；

A3 is homogenizing annealing：Homogenizing annealing is to be heated to anneal when 460-560 DEG C of constant temperature 5-15 is small by ingot casting, Residual stress, elimination or the imbalance crystal tissue for mitigating inside ingot of ingot casting are eliminated by homogenizing annealing, it is final to be promoted The anodized surface quality of extrudate.

A4 is the preheating before ingot casting squeezes：Difficulty is squeezed by preheating to reduce, and controls the hardening heat of extrudate, is protected It has demonstrate,proved extrudate and has reached maximum intensity after T6 heat treatments；

A5 is extrusion forming：By extrusion process, obtain shape and meet the extrudate of drawing requirement, and pass through control Squeezing parameter adjusts the press quenching temperature of extrudate so that extrudate reaches preferable mechanics after T6 heat treatments Performance；

A6 is press quenching：Press quenching be by squeeze fever make extrudate brought out from mould outlet reach come after >= 440 DEG C of solid solution condition, being obtained by press quenching has certain solid solubility blank, creates conditions to further improve performance；

A7 is aging strengthening model：When aging strengthening model is that constant temperature 8-16 is small in the range of 90-200 DEG C, at timeliness heat Reason promotes the η MgZn inside alloy₂Phase and TAl₂Mg₃Zn₃Precipitation strength mutually occurs, reaches the final mechanical property of extrudate Desired value.

A8 is scale sawing：Scale sawing obtains the section bar that length meets drawing requirement；

A9 is artificial anodic oxidation：One layer of fine and close anode oxide film is formed in aluminium shape surface by artificial anodic oxidation Section bar is protected, and reaches certain decorative effect.

Following table is table 1, is that alloying component compares in each embodiment and comparative example in table 1.

Following table is table 2, is each embodiment and comparative example Contrast on effect in table 2.

T4 states in heat treatment process refer to after the admittedly molten heat treatment of material natrual ageing to basicly stable state, T6 states The state of artificial aging is carried out after the solid molten heat treatment of finger, T73 states refer to quite out of fashion effect state.Aluminium alloy of the present invention Mainly for the manufacture of the structural member of electronic product.Structural member refers to definite shape structure, and can bear the effect of load Component, include but not limited to stent, skeleton, the furniture of interior of aircraft of the pedestal of machine, the shell of electronic product and inside Frame.

The constituent content referred in all embodiments and comparative example refers to the weight percent shared by the element.

Compared to more traditional Al-Zn systems wrought aluminium alloy, aluminium alloy of the invention has more excellent comprehensive performance, by force Degree more high-tensile and yield strength reach more than 400Mpa, have excellent corrosion resistance intercrystalline corrosion within 2 grades, with It 6XXX and is not added with the 7XXX wrought aluminium alloys of Cu elements and compares, the chemical polishing time of anodic oxidation pretreatment stage can contract Half is short to 1/3rd, compared with other 7XXX wrought aluminium alloys of the copper coin cellulose content more than or equal to 0.5%, this Alloy in invention efficiently solves silvery white anodic oxidation colour cast problem, and the oxide-film that material obtains after anodic oxidation is more thin Greasy beauty.

The invention is not limited in the above embodiment, if the various changes or deformation to the present invention do not depart from the present invention Spirit and scope, if these changes and deformation belong within the scope of the claim and equivalent technologies of the present invention, then this hair It is bright to be also intended to comprising these changes and deformation.

Claims (6)

1. a kind of 7XXX aluminum alloy extrusion section bars, it is characterised in that the composition of aluminium alloy each component is distinguished by weight percentage For：

Zinc：6.60%~7.00%；Magnesium：1.25%；Copper：0.18%~0.44%；Also contain iron in the aluminium alloy, iron is most High weight percent is 0.12%；Also contain silicon in the aluminium alloy, the highest weight percent of silicon is 0.06%；Also comprising altogether It is up to the impurity generated under 0.10% manufacturing condition to count weight percent, and the weight percent of each impurity is up to 0.03%, manganese content≤0.03% in the impurity, chromium content≤0.03%, the weight percentages total highest of the manganese and chromium For 0.03%；Surplus is aluminium；

Its metal grain is organized as perfect recrystallization equi-axed crystal, and crystal grain distribution is uniform, and average grain diameter is 85 μm.

2. 7XXX aluminum alloy extrusion section bars according to claim 1, it is characterised in that：The composition of each component percentage by weight It is respectively than meter：Zinc：6.8%~7.0%；Magnesium：1.25%；Copper：0.20%~0.24%；Surplus is aluminium.

3. 7XXX aluminum alloy extrusion section bars according to claim 1, it is characterised in that：Contain gallium in the impurity, gallium Highest weight percent is 0.02%.

4. 7XXX aluminum alloy extrusion section bars according to claim 1, it is characterised in that：Contain vanadium in the impurity, vanadium Highest weight percent is 0.02%.

5. 7XXX aluminum alloy extrusion section bars according to claim 1, it is characterised in that：Contain zirconium in the impurity, zirconium Highest weight percent is 0.02%.

6. according to Claims 1 to 5 any one of them 7XXX aluminum alloy extrusion section bars, it is characterised in that：For manufacturing electronics The structural member of product and for manufacturing the shell decorative product that can carry out pole oxidized surface processing.