A heat-resistant aluminum alloy material and a method for manufacturing the same

Abstract

This invention discloses a heat-resistant aluminum alloy material and its preparation method. The alloy uses pure aluminum as the matrix, with copper (Cu) as the main alloying element and a multi-element formulation of manganese (Mn), yttrium (Y), magnesium (Mg), vanadium (V), and titanium (Ti) as microalloying elements. By controlling the morphology, distribution, and size of the precipitated phases, grain boundary stability is improved, effectively suppressing creep deformation at high temperatures and simultaneously enhancing the high-temperature tensile strength of the aluminum alloy. Preparation method: First, high-purity aluminum granules are added to an electromagnetic induction furnace. Then, the remaining elements are added sequentially from highest to lowest content (magnesium is added after degassing at a temperature of 700-730℃). A refining agent is then added, and after stirring, the mixture is cast and subjected to solution treatment and aging. Tensile property testing shows a tensile strength of 238 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-copper alloys possess advantages such as high strength and significant heat treatment strengthening effects, making them the most widely used medium-temperature heat-resistant lightweight structural materials suitable for high-temperature components in aerospace, rail transportation, and power equipment. However, existing traditional aluminum-copper heat-resistant alloys have relatively simple composition systems, primarily relying on the Al2Cu phase for strengthening. Under long-term high temperatures and loads above 200 °C, the strengthening phase tends to coarsen and dissolve back, leading to easy grain growth in the alloy. This results in a significant decrease in high-temperature strength, creep resistance, and dimensional stability, limiting service temperature and service life.

[0003] Existing technologies mostly employ a single micro-alloying method to improve heat resistance, but the modification effect is limited, and it is difficult to simultaneously achieve grain stabilization, grain boundary strengthening, and high-temperature second-phase stabilization. Conventional alloys generally suffer from problems such as rapid degradation of high-temperature mechanical properties, insufficient creep resistance, and poor thermal stability, which cannot meet the high-temperature, long-term service requirements of high-end equipment.

[0004] To overcome the above limitations, this patent modifies the material by adding microalloying elements such as manganese (Mn), vanadium (V), titanium (Ti), magnesium (Mg), and yttrium (Y), giving it good mechanical properties at 350℃. Summary of the Invention

[0005] The purpose of this invention is to disclose a heat-resistant aluminum alloy material and its preparation method. The alloy uses pure aluminum as the matrix, with copper (Cu) as the main alloying element and a multi-element formulation of microalloying elements manganese (Mn), yttrium (Y), magnesium (Mg), vanadium (V), and titanium (Ti). By controlling the morphology, distribution, and size of the precipitated phases, grain boundary stability is improved, effectively suppressing creep deformation at high temperatures and simultaneously enhancing the high-temperature tensile strength of the aluminum alloy. Modification is achieved by adding microalloying elements such as manganese (Mn), vanadium (V), titanium (Ti), magnesium (Mg), and yttrium (Y). This invention uses an aluminum-copper alloy as the matrix, with Cu as the main strengthening element. After heat treatment, a large amount of θ' strengthening phase precipitates, providing the alloy with basic room temperature and high-temperature strength. Mg can synergistically precipitate with Cu, promoting the formation of fine, dispersed strengthening phases, further improving the alloy's room temperature strength and medium-to-high-temperature mechanical properties, achieving a composite precipitation strengthening effect. Mn has a significant grain-refining effect, inhibiting grain growth and recrystallization behavior at high temperatures, stabilizing the matrix structure, and effectively improving the alloy's high-temperature strength and creep resistance. Ti acts as a heterogeneous nucleation element in the melt, refining the as-cast grains, homogenizing the alloy microstructure, improving the stability of the high-temperature microstructure, and reducing microstructural defects. V precipitates highly stable Al3V dispersed particles in the matrix, effectively pinning dislocations, stabilizing the θ' strengthening phase, significantly delaying the high-temperature softening rate of the alloy, and improving the high-temperature microstructure's resistance to coarsening. Rare earth Y is a core heat-resistant modifying element. At high temperatures, it reacts with Al and Cu to form thermodynamically stable Al8Cu4Y intermetallic compounds, which can act as heterogeneous nucleation cores to refine α-Al grains and promote microstructure homogenization. Simultaneously, Y enrichment at grain boundaries improves the morphology of the grain boundary second phase, inhibits the precipitation of coarse network Al2Cu brittle phases, reduces the alloy's hot cracking tendency, and improves plasticity. Furthermore, rare earth Y can significantly improve the thermal stability of precipitated phases, effectively delaying the coarsening and phase transformation of the strengthening phase under high-temperature conditions of 300–350℃, significantly improving the alloy's high-temperature creep strength and long-term service stability. Through a multi-faceted synergistic mechanism of Cu-Mg main phase strengthening, Mn-Ti microstructure refinement, V phase stabilization, and rare earth Y grain boundary modification, the alloy of this invention achieves comprehensive properties of high strength, high heat resistance, and high microstructure stability. Attached Figure Description Figure 1 Stress-strain curves of high-temperature mechanical tensile properties at 350 degrees Celsius. Figure 2 Metallographic diagram of cast aluminum alloy Figure 3 Metallographic diagram of the heat-treated aluminum alloy Detailed Implementation

[0006] 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 at a temperature of 750-820℃, and add Al-Mn master alloy, Al-V master alloy, Al-Y master alloy and Al-Ti master alloy in sequence at a temperature of 720-770℃.

[0007] (2) When refining, removing slag and degassing the aluminum alloy melt in step (1), the stirring speed is 80-150 r / min, and then high-purity magnesium particles are added at a temperature of 700-730℃. (3) Add 0.15%-0.25% of a refining agent (aluminum pentadienyl boron) to the aluminum alloy melt in step (2) at 710-740℃ and stir at a stirring speed of 150-250 r / min; (4) The aluminum alloy melt from step (3) is poured into a mold preheated to 280-320°C at 690-720°C and air-cooled to obtain an aluminum alloy ingot. (5) The aluminum alloy ingot from step (4) is subjected to solution treatment at 510-535℃ for 6-10 hours, and then water quenched at 60-80℃ (the water quenching time is strictly controlled within 20 seconds).

[0008] (6) The aluminum alloy ingot from step (5) is aged at 165-190℃ for 7-9 hours, and then air-cooled.

[0009] 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 copper sheet has a purity ≥ 99.99%; the Al-Mn master alloy is, for example, an Al-10Mn master alloy or an Al-20Mn master alloy, with a purity ≥ 99%, the purity being the sum of Al and Mn elements; the Al-Y master alloy is, for example, an Al-10Y master alloy or an Al-20Y master alloy, with a purity ≥ 99%, the purity being the sum of Al and Y elements; the Al-V master alloy is, for example, an Al-10V master alloy or an Al-20V master alloy, with a purity ≥ 99%, the purity being the sum of Al and V elements; the Al-Ti master alloy is, for example, an Al-10Ti master alloy or an Al-20Ti master alloy, with a purity ≥ 99%, the purity being the sum of Al and Ti elements.

[0010] Performance test results of aluminum alloy .

Claims

1. A novel heat resistant aluminum alloy material, characterized by It consists of the following components by weight percentage: Cu 5.0%-6.5%, Mn 0.2%-1.2%, Mg 0.2%-0.3%, Y 0.1%-0.3%, V 0.15%-0.30%, Ti 0.05%-0.20%, with the balance being Al and unavoidable impurities.

2. The heat resistant aluminum alloy material according to claim 1, wherein The weight percentage of Cu is 5.5%-6.1%, the weight percentage of Mn is 0.25%-0.60%, the weight percentage of V is 0.18%-0.25%, the weight percentage of Ti is 0.10%-0.15%, and the mass ratio of V to Y is 1.8-2.

2.

3. The alloy according to claims 1-2 has a tensile strength of 235 MPa or higher at 350°C.

4. A heat resistant aluminum alloy material refiner (Al5TiB) characterized by The mass percentage is 0.15%-0.25%.

5. A method of producing a heat-resistant aluminum alloy material according to any one of claims 1 to 4, characterized by, Includes the following steps: S1: High-purity magnesium granules are added after degassing when the temperature is 700-730℃; S2: The refining agent (aluminum pentatitanium boron) is added at a temperature of 710-740℃. S3: Melt according to the proportion and then cast. The casting temperature is 690-720℃, and the mold is preheated to 280-320℃. S4: The ingot is solution treated at 510-535℃ for 6-10 hours, followed by water quenching at 60-80℃ (the water quenching time is strictly controlled within 20 seconds). S5: Aluminum alloy ingots are aged at 165-190℃ for 7-9 hours, followed by air cooling.

6. A method of producing a heat-resistant aluminum alloy material according to any one of claims 1 to 5, characterized by, The stirring speed during degassing is 80-150 r / min, and the stirring speed after adding the refining agent is 150-250 r / min.

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