A heat-resistant aluminum alloy material and its preparation method

Abstract

This invention discloses a novel heat-resistant aluminum alloy material and its preparation method. The material is formulated with aluminum (Al) as the substrate, copper (Cu) and zinc (Zn) as the main alloying elements, and magnesium (Mg), manganese (Mn), chromium (Cr), and titanium (Ti) as microalloying elements. The preparation method involves first adding pure aluminum to an electromagnetic induction furnace, then adding the remaining elements in descending order of content (magnesium and zinc are added after degassing at approximately 700-730℃). After degassing, slag is removed, the mixture is stirred, and then cast. Solution treatment and aging are then performed. Tensile property testing shows that the material achieves a tensile strength of 206 MPa at 350℃.

Description

Technical Field

[0001] This invention relates to a heat-resistant aluminum alloy material and its preparation method. Background Technology

[0002] Aluminum alloys possess numerous advantages, including low density, high specific strength, excellent machinability, and superior thermal and electrical conductivity, leading to their widespread application in aerospace and high-temperature structural components. Common heat-resistant aluminum alloys, such as Al-Cu and Al-Si alloys, primarily enhance their high-temperature performance by adding elements like Cu, Mn, and Zr to form dispersed precipitates. Preparation typically employs casting, extrusion, and heat treatment processes. However, in environments exceeding 300°C, the primary strengthening phases (such as the θ′-Al₂Cu phase) in existing heat-resistant aluminum alloys rapidly coarsen and transform into equilibrium phases, resulting in a sharp decline in the material's high-temperature strength. This is particularly problematic for components such as automotive engine pistons, aircraft skin materials, and compressor blade materials, where the creep resistance of traditional materials is insufficient for long-term service at 350°C. Therefore, this invention aims to provide a novel heat-resistant aluminum alloy material that maintains high tensile strength and creep resistance even at 350°C. Summary of the Invention

[0003] The purpose of this invention is to provide a novel heat-resistant aluminum alloy and its preparation method. By designing a multi-element formula including copper (Cu), zinc (Zn) as the main alloying elements and microalloying elements titanium (Ti), manganese (Mn), chromium (Cr), and magnesium (Mg), the material conditions for the formation of thermally stable strengthening phases in the heat-resistant aluminum alloy can be created. The composite addition of Mn, Ti, and Cr can inhibit alloy recrystallization, promote the fine and dispersed precipitation of the η′ phase, and change the continuous chain distribution of grain boundary precipitates to a discontinuous strip distribution, thereby improving the alloy's yield strength, tensile strength, and elongation, reducing intergranular corrosion depth, lowering corrosion current density, increasing polarization resistance, and enhancing the alloy's mechanical properties and corrosion resistance. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 Stress-strain curves of high-temperature mechanical tensile properties at 350℃; Figure 2 The image shows the metallographic structure of the as-cast aluminum alloy. Figure 3 This is a metallographic diagram of the aluminum alloy after heat treatment. Detailed Implementation

[0004] This invention also provides a method for preparing the above-mentioned heat-resistant aluminum alloy, the steps of which are as follows: Example 1 (1) Place high-purity aluminum granules into an electromagnetic induction furnace. When the aluminum granules melt into aluminum liquid, add high-purity copper sheets, Al-Mn master alloy, Al-Cr master alloy and Al-Ti master alloy in sequence at a temperature of 700-800℃.

[0005] (2) Refine, remove slag and degas the aluminum alloy melt from step (1), and then add high-purity magnesium granules and high-purity zinc granules in sequence at a temperature of 700-730℃.

[0006] (3) Stir the aluminum alloy melt from step (2) at 700-730℃ at a stirring speed of 120-240 r / min; (4) The aluminum alloy melt from step (3) is poured into a mold preheated to 270-330°C at 700-730°C and air-cooled to obtain an aluminum alloy ingot. (5) The aluminum alloy ingot from step (4) is solution treated at 510-535℃ for 7-9 hours, and then water quenched at 40-80℃. (6) The aluminum alloy ingot from step (5) is aged at 165-190℃ for 7-9 hours, and then air-cooled.

[0007] In step (1), the high-purity aluminum particles have a purity ≥ 99.99%; the high-purity magnesium particles have a purity ≥ 99.99%; the high-purity zinc particles have a purity ≥ 99.99%; the high-purity copper sheet has a purity ≥ 99.99%; the Al-Ti master alloy is an Al-10Ti master alloy or an Al-20Ti master alloy with a purity ≥ 99%, where the purity is the sum of Al and Ti elements; the Al-Cr master alloy is, for example, an Al-10Cr master alloy or an Al-20Cr master alloy with a purity ≥ 99%, where the purity is the sum of Al and Cr elements; the Al-Mn master alloy is, for example, an Al-10Mn master alloy or an Al-20Mn master alloy with a purity ≥ 99%, where the purity is the sum of Al and Mn elements.

Claims

1. A novel heat-resistant aluminum alloy material, characterized in that... It is composed of the following components by weight percentage: Cu 5.5%-6.5%, Mn 0.1%-0.3%, Mg 0.3%-0.6%, Zn 1.0%-1.5%, Ti 0.05%-0.15%, Cr 0.1%-0.2%. , The balance consists of Al and unavoidable impurities.

2. The heat-resistant aluminum alloy material according to claim 1, characterized in that, The weight percentage of Cu is 5.8%-6.3%, and the weight percentage of Mg is 0.35%-0.5%.

3. A method for preparing a heat-resistant aluminum alloy material as described in any one of claims 1 to 2, characterized in that, Includes the following steps: S1: High-purity magnesium granules and zinc granules are added after degassing when the temperature is around 700-730°C; S2: Melt according to the proportion and then cast. The casting temperature is 700-730℃, and the mold is preheated to 270-330℃. S3: The ingot is solution treated at 510-535℃ for 7-9 hours, followed by water quenching at 40-80℃; S4: Aluminum alloy ingots are aged at 165-190℃ for 7-9 hours, followed by air cooling.

4. A method for preparing a heat-resistant aluminum alloy material as described in any one of claims 1 to 2, characterized in that, The stirring speed is 120-240 r / min.

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