A build-up forming method for an aluminum alloy deformed member

Abstract

The application provides a construction forming method suitable for aluminum alloy deformed parts and belongs to the technical field of metal material preparation. The construction forming method comprises the following steps: preparing a plurality of homogeneous aluminum alloy elements subjected to short-time homogenization treatment, and stacking the plurality of elements into a predetermined shape; packaging the plurality of elements stacked into the predetermined shape into a preform blank; placing the preform blank in a hot pressing device to perform high-temperature, short-time and low-deformation hot pressing and heat preservation, so as to obtain a pre-deformed blank; placing the pre-deformed blank after heat preservation in a heat treatment furnace to perform secondary homogenization annealing; and performing forging forming on the pre-deformed blank after annealing, so as to obtain a high-quality aluminum alloy forging. The time of the conventional homogenization annealing process of the aluminum alloy is matched with the hot pressing diffusion connection process, the number and size of the interface oxide films are effectively controlled, high-quality connection is realized, the subsequent deformation requirement is met, and the problem that the performance of the construction forming product is low due to the excessively large size of the interface oxide film and the product cannot be applied can be effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of metal material preparation technology, and relates to a construction and forming method suitable for aluminum alloy deformable parts. Specifically, it is a processing method for deforming and forming aluminum alloy materials through construction. Background Technology

[0002] Aluminum alloys, with their advantages of low density, high strength, good overall performance, and excellent plasticity, have become one of the most outstanding metals in industrial development, and are widely used in the automotive, aerospace, and electronics and communications industries. Technological advancements and continuous industrial development have placed higher demands on the aluminum alloy materials used, such as high strength, corrosion resistance, and low yield rates, especially for large-size aluminum alloy critical structural components, where quality assurance is difficult and the uniformity of microstructure and properties is challenging to control.

[0003] Metal construction forming technology utilizes the concept of "making large with small" to form multiple homogeneous slabs. After surface processing, cleaning, stacking and vacuum sealing, the slabs are then subjected to deformation joining processes characterized by high-temperature pressure forging and multi-directional forging. This not only achieves a "seamless" connection where the interface and the substrate are completely consistent, but also improves the product's productivity and yield.

[0004] Compared to the construction forming technology for stainless steel and alloy steel, aluminum alloys, due to their low melting point, have difficulty effectively decomposing the highly thermally stable and dense aluminum oxide film. Therefore, it is necessary to develop construction forming technology suitable for aluminum alloy products to solve the problem of aluminum alloy surface oxide film. Summary of the Invention

[0005] The purpose of this invention is to provide a construction forming method suitable for aluminum alloy deformable parts, so as to solve the problems existing in the prior art. It can effectively solve the problem that the performance of the constructed forming product is low and cannot be applied due to the excessive size of the oxide film at the interface.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A method for constructing and forming aluminum alloy deformable parts is disclosed. This method utilizes the time of the conventional homogenization annealing process of aluminum alloys and the hot-pressing diffusion bonding process to effectively control the quantity and size of the interface oxide film, achieving high-quality bonding and meeting the requirements of subsequent deformation. Specifically, it includes the following steps:

[0008] The first step involves preparing multiple small-volume homogeneous aluminum alloy units using as-cast aluminum alloys and performing a first-stage homogenization annealing treatment, with the annealing time being t1.

[0009] The second step is to stack multiple homogeneous aluminum alloy elements after annealing into a predetermined shape to produce a preform.

[0010] Third step, put the preform in the hot pressing device, high temperature (T 热压 ), short time (t2), low deformation (δ) heat preservation diffusion connection, through heat preservation and pressure, the surface of the aluminum alloy element oxide film is quickly broken, and the interface is initially healed to form a whole, and a pre-deformation blank is obtained.

[0011] Fourth step, put the pre-deformation blank after heat preservation in the heat treatment furnace for long time (t3) secondary homogenization annealing, the broken oxide film is secondarily decomposed into nano-sized particle phase.

[0012] Fifth step, plastic forming of the annealed pre-deformation blank, complete the final construction forming, and obtain high-quality aluminum alloy forgings.

[0013] Further, the aluminum alloy element needs to be a cast blank without any heat treatment, and the aluminum alloy is 2 series, 5 series, 6 series and 7 series and other deformation aluminum alloys and other aluminum alloy metal materials that can be used for construction forming. These materials are usually deformable alloys used to prepare various forgings, rolled pieces or extruded pieces. The shape of the aluminum alloy element is usually cuboid or cylindrical.

[0014] Further, the first stage homogenization time t1≥1h ensures the stress relief annealing effect of the ingot in the homogenization process. The time should not be too long, and sufficient time should be left for the hot pressing process and the subsequent heat treatment process, generally not more than 0.5t 均 , t 均 is the conventional homogenization annealing time of the selected aluminum alloy.

[0015] Further, the stacking of the element means arranging multiple aluminum alloy elements into multiple layers to make a preform, and each layer includes an element.

[0016] Further, the shape of the preform is based on the deformation process requirements of specific aluminum alloy products.

[0017] Further, the hot pressing heating temperature T 热压 is one of the keys to affect the decomposition of the aluminum alloy oxide film. The temperature should be as high as possible, but not higher than the solid solution temperature of the alloy. Therefore, the hot pressing temperature range needs to meet T 固 >T 热压 ≥0.95T 固 , T 固 is the solid solution temperature of the selected aluminum alloy material, unit: ℃. Usually, the temperature can be directly selected as the homogenization annealing temperature.

[0018] Further, the hot pressing time t2 is one of the keys to ensure the decomposition of the oxide film, and a long time is generally required, usually t2≥1h, but since sufficient time is required for subsequent secondary homogenization annealing, t2 should not exceed 0.2t 均 .

[0019] Further, the deformation amount refers to plastic deformation of the preform under a certain pressure during hot pressing to achieve the preliminary physical cracking of the oxide film. Generally, the holding pressure P≥1MPa, because the deformation amount δ≤20% of the aluminum alloy needs to be controlled in a reasonable aluminum alloy deformation temperature range.

[0020] Further, the sealing refers to vacuum sealing and welding treatment of the contact surface formed due to stacking under the condition of non-vacuum hot pressing, to ensure that there is no air remaining between the contacts of the aluminum alloy elements, and no air leakage during subsequent hot pressing and heat treatment.

[0021] Further, the secondary homogenization annealing refers to placing the pre-deformation sample in a conventional heat treatment furnace for homogenization annealing treatment after hot pressing. The homogenization annealing time t3≥t 均 -t1-t2, the total homogenization annealing time cannot be less than t 均 .

[0022] The beneficial effects of the present application are as follows:

[0023] The present application utilizes the high-temperature short-time hot pressing diffusion process to rapidly break the oxide film and interact with the interfacial second phase, and then utilizes secondary homogenization annealing treatment to refine the oxide again, so that it is converted into a nano-level particle phase, significantly reducing the influence of the interfacial oxide film on the use, and can be directly used for subsequent deformation processing to manufacture the required products. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Schematic diagram for preparing a preform of aluminum alloy elements;

[0025] Figure 2 Interface oxide morphology diagram of an aluminum alloy pre-deformation blank after hot pressing diffusion connection;

[0026] Figure 3 Interface oxide morphology diagram of an aluminum alloy pre-deformation blank after secondary homogenization annealing. DETAILED DESCRIPTION

[0027] The present application will be further described below in combination with specific implementation cases.

[0028] The embodiment selects 2219 aluminum alloy for forging. Four 2219 aluminum alloy as-cast base elements with a size of Φ100mm*30mm are selected, the conventional homogenization annealing temperature of the alloy is 540℃ / 24h, therefore, the first homogenization annealing selects a heat treatment process of 540℃ / 6h, heating and holding in a heat treatment furnace, after completion, taking out and air cooling and combining into two preformed blanks with one interface.

[0029] The two preformed blanks are respectively subjected to hot pressing diffusion connection experiment in a vacuum hot pressing device, Z-axis direction pressing shown in the schematic diagram of the preformed blank of the aluminum alloy element is adopted, the pressure is 5MPa. Figure 1 The preformed blank of the aluminum alloy element is prepared, Z-axis direction pressing shown in the schematic diagram of the preformed blank of the aluminum alloy element is adopted, the pressure is 5MPa. The hot pressing holding temperature is the same as the homogenization annealing temperature, which is 540℃, and the total holding time is 2h, and the deformation amount is controlled to be 20% through the die.

[0030] After the diffusion connection is completed, two pre-deformed blanks are obtained, one of the pre-deformed blanks is again put into a heat treatment furnace, held at 540℃ for 16h, and then the sample is taken out and air cooled. For the hot pressing diffusion sample and the second homogenization annealing sample, the interface position is cut by a double-beam focused ion beam (FIB) for transmission microscope (TEM) observation.

[0031] Figure 2 For the aluminum alloy pre-deformed blank only after hot pressing diffusion connection, only the interface structure characteristics, as can be seen from the figure, there are gray second phase wrapped long strip-shaped white oxide particle phases at the interface, the length of the oxide phase is about 1μm or so; Figure 3 For the aluminum alloy pre-deformed blank after the second homogenization annealing, only the interface structure characteristics, as can be seen from the figure, a large number of gray second phases at the interface disappear, no obvious white oxide particle phase is found in the residual phase, and a small amount of 100-200nm scale white particle phase is found at the grain boundary. Obviously, the oxide film of the sample after hot pressing diffusion connection and the second homogenization annealing treatment is greatly eliminated, which provides an important guarantee for the subsequent deformation process and performance stability.

[0032] The above-described embodiments are only descriptions of preferred modes of the present application, and do not limit the scope of the present application, without departing from the design spirit of the present application, various deformations and improvements of the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A build-up forming method suitable for an aluminum alloy deformed member, characterized by, The building forming method comprises the following steps: In the first step, a plurality of small-volume homogenous aluminum alloy base elements after first-stage homogenization annealing treatment are prepared, wherein the annealing treatment time is t1; In the second step, the plurality of homogenous aluminum alloy base elements after annealing treatment are stacked into a predetermined shape to form a preform; Thirdly, the preform is placed in a hot pressing device for heat pressing, heat preservation and diffusion bonding, so that the interface is healed to form a whole, and a pre-deformed blank is obtained; wherein the hot pressing temperature is T 热压 , the hot pressing time is t2, and the deformation amount is δ. The hot-pressing heating temperature T 热压 satisfies: T 固 > T 热压 ≥ 0.95T 固 , T 固 is a solid solution temperature of the selected aluminum alloy material; The hot pressing time t2 is greater than or equal to 1 hour and does not exceed 0.2t 均 , t 均 is a conventional homogenization annealing time of the selected aluminum alloy. In the hot pressing process, pressure holding is required, the pressure P≥1 MPa, and the deformation amount δ of the aluminum alloy is controlled to be ≤20%; In the fourth step, the pre-deformed blank after holding is placed in a heat treatment furnace for long-time secondary homogenization annealing, wherein the secondary homogenization annealing time is t3; In the fifth step, the pre-deformed blank after annealing is subjected to plastic forming to complete the final building forming and obtain a high-quality aluminum alloy forging.

2. A build-up forming method for an aluminum alloy wrought material according to claim 1, characterized by, The aluminum alloy base element is an uncast blank, and the aluminum alloy is a 2-series, 5-series, 6-series, and 7-series wrought aluminum alloy and other aluminum alloy metal materials that can be used for building forming.

3. A build-up forming method for an aluminum alloy wrought material according to claim 1, characterized by, The first stage homogenization time t1≥ 1 h and is not more than 0.5t 均 .

4. A build-up forming method for an aluminum alloy wrought material according to claim 1, characterized by, The stacking of the base element means that a plurality of aluminum alloy base elements are arranged into multiple layers to form a preform, and each layer includes one base element.

5. The building forming method suitable for aluminum alloy wrought parts according to claim 1, characterized in that The aluminum alloy can be subjected to hot pressing diffusion bonding under non-vacuum or vacuum conditions.

6. A build-up forming method for an aluminum alloy wrought material according to claim 5, characterized by, When the aluminum alloy is subjected to hot pressing diffusion bonding under non-vacuum conditions, the preform needs to be subjected to vacuum sealing treatment.

7. A build-up forming method for an aluminum alloy wrought material according to claim 1, characterized by, The secondary homogenization annealing time t3≥t 均 -t1-t2.

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