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CN-121380639-B - High-strength aluminum alloy for 3C electronic product and preparation method thereof

CN121380639BCN 121380639 BCN121380639 BCN 121380639BCN-121380639-B

Abstract

The application provides a high-strength aluminum alloy for 3C electronic products and a preparation method thereof, which comprises six steps of smelting, refining, casting forming, homogenizing treatment, quenching and aging, wherein the content of Fe and Cu is strictly reduced, the atomic ratio of Mg and Si is improved, the preparation process of the aluminum alloy is optimized, the synergistic effect of Al, mg and Si is ensured, the strengthening phase is promoted to be evenly and stably separated out, the formation of a coarse G.P. region after the aluminum alloy is quenched at room temperature can be avoided, the high dispersion requirement of the strengthening phase is met, and the mechanical property of the aluminum alloy is remarkably improved. The yield strength of the aluminum alloy is 288MPa-305MPa, the tensile strength is 302MPa-313MPa, the precision range of the fitting after being processed into a 3C product fitting is +/-0.009 mm- +/-0.02 mm, the surface color difference delta E of the fitting after anodic oxidation is 0.31-0.45, and the tolerance fluctuation rate and the color difference fluctuation rate are all lower than 7%. The aluminum alloy does not need to be added with expensive metal, has uniform crystalline phase structure, has high strength and high plasticity, is convenient to popularize and implement, and can meet the processing requirements of 3C electronic products and ultra-high precision medical instruments.

Inventors

  • Li Zhilue
  • PAN BAOWEN
  • WANG HAIDONG
  • ZHU FENGCHUN

Assignees

  • 广东金铝轻合金股份有限公司

Dates

Publication Date
20260508
Application Date
20251225

Claims (6)

  1. 1. The preparation method of the high-strength aluminum alloy for the 3C electronic product is characterized by comprising the following steps of: Sequentially adding an aluminum source, a silicon source, an iron source, a copper source, a manganese source, a magnesium source, a chromium source, a zinc source and a titanium source into a high-frequency induction smelting furnace, stirring for 30-50 min under the conditions of 740-760 ℃ and electromagnetic stirring frequency of 200-500 Hz, sampling from the high-frequency induction smelting furnace at regular time in the stirring process, analyzing, controlling each component in the melt to be in a preset interval, and obtaining a first melt after stirring is completed; Refining, namely sequentially adding a refiner and a refining agent into the first melt, standing for 20-30 min, and degassing and deslagging to obtain a second melt; Transferring the second melt into a casting machine, and casting the second melt into aluminum materials with preset size specifications by adopting a semi-continuous casting process under the conditions of casting speed of 80mm/min and cooling water pressure of 0.3-0.5 MPa; Homogenizing, namely transferring the prepared aluminum material into a continuous homogenizing furnace, homogenizing for 4-5 hours at 530-550 ℃, and cooling to room temperature to obtain homogenized aluminum material; Quenching, namely heating the prepared homogenized aluminum material to 510-520 ℃, transferring the homogenized aluminum material into a hot extruder, extruding the aluminum material at the die temperature of 480-490 ℃, cooling the homogenized aluminum material by a water mist cooling device after extrusion, and cooling the aluminum material to 170-180 ℃ to obtain quenched aluminum material; Aging, namely transferring the prepared quenched aluminum material into a hot air circulation aging furnace, preserving heat for 8-9 hours at 170-180 ℃ and naturally cooling to room temperature to obtain the high-strength aluminum alloy for the 3C electronic product; The high-strength aluminum alloy comprises, by mass, ：Si 0.43%-0.46%、Fe 0.07%-0.09%、Cu 0.04%-0.05%、Mn 0.03%-0.04%、Mg 0.63%-0.65%、Cr 0.02%-0.04%、Zn 0.02%-0.03%、Ti 0.06%-0.07%, of Al and unavoidable other impurity elements, wherein the total amount of the unavoidable other impurity elements is less than or equal to 0.01%, and the aluminum alloy comprises an alpha-Al-based phase and an Mg 2 Si reinforcing phase which is dispersed and distributed in the alpha-Al-based phase; The atomic ratio of Mg to Si in the aluminum alloy is 1.63-1.71; The grain size of the aluminum alloy is 12-17 mu m, and the grain size difference is 3-5 mu m; In the aluminum alloy, the grain size of the Mg 2 Si reinforced phase is 0.4-0.8 mu m, and the distance between two adjacent Mg 2 Si reinforced phase grains is 1-5 mu m; In the aluminum alloy, the average three-dimensional distribution density of Mg 2 Si reinforced phases in single grains is 2.4x10 7 /mm 3 -3.9×10 7 /mm 3 ; in the aluminum alloy, the number of Mg 2 Si strengthening phases in a single crystal grain is 33-84; In the aluminum alloy, the volume fraction of Mg 2 Si reinforced phase in a single crystal grain is 0.22-0.43%; defining the total quantity of Mg 2 Si strengthening phases in the aluminum alloy crystal grain as Z, and the quantity of Mg 2 Si strengthening phases on the alpha-Al base phase crystal boundary as Y, wherein the Z and the Y satisfy the following relation that the concentration of the Mg 2 Si strengthening phases is 89.8 percent to less than or equal to (Z-Y)/the concentration of the Z is less than or equal to 94.3 percent.
  2. 2. The method for producing a high-strength aluminum alloy for 3C electronics according to claim 1, wherein the homogenizing step comprises a heating stage, a heat-retaining stage, and a cooling stage; The temperature rising stage is to heat the aluminum material from room temperature to 535 ℃ to 545 ℃ with the corresponding temperature rising rate of 4.5 ℃ per minute to 5 ℃ per minute; the heat preservation stage is to preserve the aluminum material for 4 to 5 hours at the temperature of 535 to 545 ℃; The cooling stage is to cool the aluminum material from 535 ℃ to 545 ℃ to room temperature, and the corresponding cooling speed is 20 ℃ per second to 50 ℃ per second; And cooling the aluminum material by adopting cooling water in the cooling stage, wherein the flow rate of the cooling water is 50L/min-60L/min.
  3. 3. The method for preparing a high-strength aluminum alloy for 3C electronic products according to claim 1, wherein the flow rate of water mist is 25L/min-30L/min and the cooling rate of water mist is 15 ℃ per second-25 ℃ per second in the quenching process.
  4. 4. The method for producing a high-strength aluminum alloy for 3C electronic products according to claim 1, wherein the temperature fluctuation of the hot air circulating aging furnace is defined as X in the aging process, wherein X satisfies the following relationship that X is not less than 1 ℃ and not more than 2.5 ℃.
  5. 5. The method for producing a high-strength aluminum alloy for 3C electronic products according to claim 2, wherein the Mg 2 Si strengthening phase approaches a supersaturated solid solution state during the cooling stage and the mist cooling process.
  6. 6. The use of a high strength aluminum alloy for 3C electronics, characterized in that the aluminum alloy is prepared by a method for preparing a high strength aluminum alloy for 3C electronics as claimed in any one of claims 1 to 5; The aluminum alloy is used for processing any one of a laptop shell frame, a laptop chip supporting frame, a laptop screen backboard, a laptop internal supporting beam, a mobile phone metal middle frame, a mobile phone front and back frame, an intelligent watch shell, a heat radiation module pipeline, a mobile phone camera fixing support, an unmanned aerial vehicle support, a battery pack internal support and a numerical control medical instrument metal part.

Description

High-strength aluminum alloy for 3C electronic product and preparation method thereof Technical Field The application belongs to the technical field of metallurgy, and particularly relates to a high-strength aluminum alloy for a 3C electronic product and a preparation method thereof. Background In the prior art, aluminum alloy has become a core light material of a 3C product structural member (frame, bracket and internal customized special-shaped member) and an appearance member (shell and decoration panel) due to low density, good plasticity and excellent specific strength, so that key support is provided for light weight and portability of the product, and the use experience and market competitiveness are effectively improved. However, with the rapid development of 3C products toward light weight, high strength, and precision (dimensional tolerance ± 0.03 mm), the mainstream 6-series aluminum alloy has obvious performance short plates, which are difficult to match with the increasingly rising production demands. In the prior art, the 6-series aluminum alloy mainly depends on Mg and Si elements for strengthening, but the existing alloy has poor proportion of the Mg and Si elements, the processing technology cannot meet the requirement of high uniform dispersion distribution of strengthening phases in the aluminum alloy, the precipitation amount of the strengthening phases is unstable, the mechanical property of an aluminum alloy finished product is obviously reduced, an obvious parking effect exists, the quenched aluminum alloy is parked at room temperature and then aged, the strengthening phases in the aluminum alloy are precipitated in advance to form a coarse G.P. area, so that stress concentration areas are formed in the aluminum alloy, the subsequent aging of the aluminum alloy is greatly and negatively influenced, and the mechanical property of the aluminum alloy is obviously reduced. Moreover, as defects exist in the dispersion distribution of the strengthening phases in the existing aluminum alloy, the uniformity degree of the base phases and the strengthening phases in the aluminum alloy is low, the surface specification of the aluminum alloy is reduced in the processing process, the processing of subsequent 3C product accessories is affected, for example, the precision of extruded products is obviously reduced in the numerical control (CNC) processing process, the accumulated error of components fluctuates, operators also need to frequently adjust numerical control processing equipment, the uniformity degree of oxide films on the surface of the aluminum alloy is reduced in the anodic oxidation process, and high chromatic aberration exists after the aluminum alloy is anodized. Therefore, development of a novel aluminum alloy which has a highly refined and uniform internal crystal phase structure, is low in production cost and meets the processing requirements of ultra-high-precision 3C electronic products is urgently needed. Disclosure of Invention The application provides a high-strength aluminum alloy for 3C electronic products, which aims to solve the technical problems that the proportion of Mg and Si elements in a 6-series aluminum alloy is poor, the processing technology is poor, the precipitation amount of a strengthening phase is unstable, the uniformity degree of a base phase and the strengthening phase is low, the requirement of high uniform dispersion distribution of the strengthening phase cannot be met, a coarse G.P. region is formed by standing at room temperature and then aging after quenching, and the mechanical property of the aluminum alloy is remarkably reduced, and meanwhile, after the aluminum alloy is processed into a 3C product accessory, the precision fluctuation of a finished product is large, the color difference fluctuation after anodic oxidation is large, the adhesion strength of an oxide film is reduced, and the requirements of thinning, high strength and precision of the 3C product are difficult to match. In order to solve the technical problem, the application also provides a preparation method of the high-strength aluminum alloy for the 3C electronic product. In order to solve the technical problem, the application also provides application of the high-strength aluminum alloy for the 3C electronic product. The application adopts the following scheme that the preparation method of the high-strength aluminum alloy for the 3C electronic product comprises the following steps: Sequentially adding an aluminum source, a silicon source, an iron source, a copper source, a manganese source, a magnesium source, a chromium source, a zinc source and a titanium source into a high-frequency induction smelting furnace, stirring for 30-50 min under the conditions of 740-760 ℃ and electromagnetic stirring frequency of 200-500 Hz, sampling from the high-frequency induction smelting furnace at regular time in the stirring process, analyzing, controlling each component in the melt to be