Novel high-temperature-resistant eutectic aluminum alloy and preparation method thereof

Abstract

The invention belongs to the technical field of aluminum alloy preparation, and particularly discloses a novel high-temperature-resistant eutectic aluminum alloy and a preparation method thereof.The high-temperature-resistant eutectic aluminum alloy comprises, by mass, 90%-97% of aluminum, 1%-3.5% of iron, 1%-3.5% of cobalt, 1%-3.5% of nickel, 0-0.5% of scandium, 0-0.5% of titanium, 0-0.5% of vanadium, 0-0.5% of zirconium and 0-1.0% of manganese. According to the aluminum alloy, an Al9 (Fe, Co, Ni) 2 eutectic phase forms a heat-resistant stable eutectic frame, Al3 (Sc, Ti, V, Zr) is introduced through microalloying to separate out a strengthening phase or a solid solution strengthening element to generate a strengthening effect, and the mechanical property of the aluminum alloy is improved in multiple dimensions. The novel high-temperature-resistant eutectic aluminum alloy provided by the invention has excellent high-temperature stability, creep deformation resistance and high-temperature comprehensive mechanical properties, and has a relatively good high-temperature application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy preparation, and in particular to a novel high-temperature-resistant eutectic aluminum alloy for use in pistons, radiators, etc., which maintains stable organizational properties during long-term exposure in a high-temperature environment, and a preparation method thereof. Background Art

[0002] Heat-resistant aluminum alloys have microstructural heat-resistant stability and good high-temperature mechanical properties. They can serve for a long time in high-temperature and load-coupled environments and are widely used in aerospace, automobile, weapons and other fields. Heat-resistant aluminum alloys can replace iron parts in automobile engine pistons, improve engine efficiency and achieve energy conservation and emission reduction. Modern industrial development requires heat-resistant aluminum alloys to work stably for a long time at temperatures above 300°C (for example, high-performance military aircraft skins, high-power density engine components, etc.). Strengthening elements such as Si, Cu, and Mg commonly used in traditional heat-resistant aluminum alloys diffuse quickly in the aluminum matrix, which can easily lead to coarsening and failure of strengthening structures at high temperatures. It has the following application problems: (I) Deterioration of high-temperature performance of Al-Si alloys. When the eutectic silicon framework is exposed to ≥300°C for a long time, it is easy to spheroidize, causing the silicon framework to break and shatter, losing the load transfer effect, and resulting in reduced high-temperature performance of the alloy. (II) High-temperature coarsening failure of the main strengthening phase. Taking θ(Al 2 Cu), S(Al 2 CuMg) and β(Mg 2 When the working temperature of the precipitation strengthening phase represented by Si is higher than 200℃, the size coarsens due to diffusion and the strengthening effect decreases. In order to effectively solve these problems and further improve the stability of aluminum alloys in high temperature and long-term thermal exposure environments, some new alloy designs have been proposed.

[0003] For example, a high temperature resistant cast aluminum alloy (CN108330343A) discloses the following alloy components: 1-2% silicon, 2-3% magnesium, 2-3% zinc, 0.13-0.15% chromium, 1.5-2.5% lithium, 0.01-0.05% zirconium, 0.1-0.15% cadmium, 0.2-0.25% antimony, 0.01-0.05% europium, and the balance is aluminum. The alloy reduces the amount of silicon added and improves its high temperature comprehensive performance by introducing other elements. However, the precipitated phase formed after the introduction of magnesium and zinc elements into the alloy also quickly loses its strengthening effect under high temperature environment. In addition, the cadmium element added in the alloy is a highly toxic element, which limits its application.

[0004] A creep-resistant and high-temperature resistant cast aluminum alloy (CN114480931A), the disclosed alloy composition is: 5.0-8.0% zinc, 2.5-3.5% magnesium, 2.0-3.0% hafnium, 0.3-0.6% gadolinium, 0.2-0.5% zirconium, and the balance is Al and impurities. The hafnium and gadolinium elements introduced into the alloy can form precipitation phases that grow along the prism surface to improve the creep performance of the alloy. However, the main elements of the alloy are still rapidly diffusing magnesium and zinc elements. In addition, the alloy grains are significantly refined, and the performance at higher temperatures is limited.

[0005] A high temperature resistant aluminum alloy (CN107739902A), the disclosed alloy composition is: 0.8-2.3% iron, 0.6-1.2% carbon, 3.2-3.5% titanium, 2.1-2.6% magnesium, 1.1-1.5% bismuth, 0.6-0.9% cesium, and the balance is aluminum. The alloy adds a large amount of titanium to replace silicon, so that the strength and high temperature performance of the alloy are improved. However, in the description of the alloy, only the compression performance of the alloy is given. Therefore, the casting performance and high temperature performance of the alloy with this composition need further demonstration. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a new high temperature resistant eutectic aluminum alloy and a preparation method thereof.

[0007] In order to achieve the above object, the specific technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a novel high temperature resistant eutectic aluminum alloy, the mass percentages of its components being: aluminum 90%-97%, iron 1-3.5%, cobalt 1-3.5%, nickel 1-3.5%, scandium 0-0.5%, titanium 0-0.5%, vanadium 0-0.5%, zirconium 0-0.5%, and manganese 0-1.0%.

[0009] The novel eutectic heat-resistant aluminum alloy provided by the present invention has a multi-scale microstructure, takes the eutectic phase as the main structural framework, introduces precipitation strengthening phase and solid solution elements into the matrix, produces strengthening effects from multiple dimensions, and improves the heat resistance and creep resistance of the matrix alloy.

[0010] The present invention selects slow-diffusion elements iron, cobalt, and nickel to replace silicon as the main additive elements to form a eutectic phase structural framework in the aluminum matrix to improve the heat-resistant stability of the aluminum alloy. Iron, cobalt, and nickel need to be added strictly according to the formula to control the total mass fraction of the three. If the total mass fraction ratio is too high, the excess elements will form a coarse second phase, causing the alloy to thermally crack when cast into ingots, or deform and crack when continuously cast and rolled into plates; if this ratio is too low, the volume of the eutectic framework structure formed is relatively low, and the corresponding high-temperature performance of the invented alloy cannot be maintained.

[0011] Preferably, the mass ratio of iron:cobalt:nickel is controlled at 1:1:1 to control the eutectic phase to be mainly Al 9 (Fe,Co,Ni) 2 .

[0012] The present invention selectively adds microalloying elements such as scandium, titanium, vanadium, and zirconium to improve the comprehensive performance of the matrix alloy by means of precipitation phase or second phase. Among them, scandium and zirconium elements, as the main elements of the precipitation phase, can precipitate in different positions such as inside the aluminum matrix and at the interface of the eutectic phase, and play a strengthening role through the Orowan mechanism or stress transfer mechanism. Titanium and vanadium have strong binding ability with iron, cobalt, and nickel atoms. The addition of these elements can enhance L1 2 -Al 3 (Sc, Zr, Ti, V) in Al 9 (Fe,Co,Ni) 2 The interface precipitation of the phase further improves the stress transfer ability of the eutectic phase and optimizes the high-temperature creep resistance of the alloy.

[0013] In a preferred embodiment of the present invention, the aluminum alloy composition includes aluminum, iron, cobalt, nickel, scandium, vanadium and zirconium. On the basis of aluminum-iron-cobalt-nickel eutectic alloy, microalloying elements scandium, zirconium and vanadium are added, and the hardness and high temperature heat resistance stability of the alloy can be significantly improved.

[0014] In a preferred embodiment of the present invention, the aluminum alloy composition includes aluminum, iron, cobalt, nickel, scandium, titanium, vanadium and zirconium. On the basis of aluminum-iron-cobalt-nickel eutectic alloy, microalloying elements scandium, titanium, zirconium and vanadium are added, and the high temperature creep resistance of the aluminum alloy is significantly improved.

[0015] The present invention selectively adds manganese as a microalloying element, which can improve the comprehensive performance of the matrix alloy by solid solution strengthening, etc. The manganese element can interact with dislocations, hinder dislocation movement, and improve the high-temperature creep resistance of the matrix.

[0016] In a preferred embodiment of the present invention, the aluminum alloy components include aluminum, iron, cobalt, nickel, scandium, titanium, vanadium, zirconium and manganese elements. The aluminum alloy not only has more superior high-temperature creep resistance, but also can maintain stable mechanical properties when exposed to high temperature for a long time.

[0017] In a second aspect, the present invention provides a method for preparing the novel high temperature resistant eutectic aluminum alloy, comprising the following steps:

[0018] S1. Weigh pure aluminum and various master alloys respectively;

[0019] S2. Place pure aluminum into a crucible and heat it to melt;

[0020] S3. After pure aluminum is melted, aluminum-iron, aluminum-cobalt and aluminum-nickel master alloys are added, and aluminum-scandium, aluminum-titanium, aluminum-vanadium, aluminum-zirconium and aluminum-manganese master alloys are selectively added, melted at high temperature and kept warm;

[0021] S4. Refining and degassing;

[0022] S5. Forming the aluminum alloy melt after the above treatment.

[0023] Preferably, in step S1, the mass percentage of each raw material is: pure aluminum 0-75.0%, aluminum-iron master alloy 5.0-17.5%, aluminum-cobalt master alloy 10.0-35.0%, aluminum-nickel master alloy 10.0-35.0%, aluminum-scandium master alloy 0.0-25.0%, aluminum-titanium master alloy 0.0-5.0%, aluminum-vanadium master alloy 0.0-5.0%, aluminum-zirconium master alloy 0.0-5.0%, aluminum-manganese master alloy 0.0-10.0%.

[0024] Preferably, in step S2, the melting temperature is 700°C-1000°C.

[0025] Preferably, in step S3, the high temperature melting and holding temperature is higher than the melting temperature in step S2 by 0-200°C, so that the intermediate alloy is fully melted, and the holding time should be controlled to ensure that the aluminum-iron, aluminum-cobalt and aluminum-nickel intermediate alloys are fully melted.

[0026] Preferably, in step S4, the refining and degassing temperature is lower than the holding temperature of 0-100°C in step S3 to avoid incomplete degassing due to excessively high temperature, resulting in more porosity defects in the ingot. The refining and degassing time should be controlled to remove as much gas as possible involved in the smelting process.

[0027] Preferably, in step S5, the melt is cast into ingots or made into wires by pouring or continuous casting and rolling. The alloy of the present invention has excellent casting performance and is suitable for direct casting of complex configurations.

[0028] The present invention has the following beneficial effects:

[0029] The present invention can prepare an aluminum alloy with excellent high-temperature heat-resistant exposure stability, creep resistance, and high-temperature comprehensive mechanical properties, and the aluminum alloy formula does not contain toxic elements and fast-diffusion elements, thus overcoming many defects of existing high-temperature resistant aluminum alloys. In addition, the aluminum alloy preparation method of the present invention is simple and suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 : Microstructure and thermal exposure stability of eutectic alloy in Example 1. In the figure, (a) is Al-Al 9 (Fe,Co,Ni) 2Microstructure morphology of binary eutectic alloy; (b) thermal exposure stability of AlFeCoNi alloy; (c) thermal exposure stability of AlFeCoNi-ScZrV alloy at 400℃.

[0031] Figure 2 : Comparison of creep properties of the series of eutectic alloys at 400°C in Examples 2 and 3. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] This embodiment provides a method for preparing a novel high temperature heat exposure resistant aluminum alloy, including the preparation of aluminum-iron-cobalt-nickel alloy and aluminum-iron-cobalt-nickel-scandium-zirconium-vanadium alloy. The specific process is as follows:

[0035] (1) Weigh aluminum and various master alloys according to the following proportions: 75.0% high-purity aluminum, 5.0% aluminum-iron master alloy (Al-20Fe), 10.0% aluminum-cobalt master alloy (Al-10Co), and 10.0% aluminum-nickel master alloy (Al-10Ni);

[0036] (2) After pure aluminum is melted at 750°C, aluminum iron, aluminum cobalt and aluminum nickel master alloy are added and melted at 850°C and kept warm. After the master alloy is fully melted, it is refined and degassed at 760°C;

[0037] (3) The above melt is directly cast into an ingot.

[0038] (4) Similarly, aluminum and various master alloys are weighed in the following proportions: 59.0% high-purity aluminum, 5.0% aluminum-iron master alloy (Al-20Fe), 10.0% aluminum-cobalt master alloy (Al-10Co), 10.0% aluminum-nickel master alloy (Al-10Ni), 10.0% aluminum-scandium master alloy (Al-2Sc), 2.0% aluminum-zirconium master alloy (Al-10Zr), and 4.0% aluminum-vanadium master alloy (Al-10V);

[0039] (5) After pure aluminum is melted at 750°C, each master alloy is added and melted at 850°C and kept warm. After the master alloy is fully melted, it is refined and degassed at 760°C;

[0040] (6) The above melt is directly cast into an ingot.

[0041] The aluminum-iron-cobalt-nickel high temperature heat exposure resistant aluminum alloy prepared in step (3) is composed of 1.0% iron, 1.0% cobalt, 1.0% nickel, and the rest is aluminum. 9 (Fe,Co,Ni) 2The aluminum-iron-cobalt-nickel alloy with this composition is Al-Al 9 (Fe,Co,Ni) 2 The microstructure of binary eutectic alloy is as follows Figure 1 a. Among them, the main structure of the alloy is eutectic structure, which can be used as the main framework of the heat-resistant aluminum alloy structure for multi-scale structural design. The alloy has excellent resistance stability under high temperature thermal exposure environment, such as Figure 1 As shown in Figure b, the hardness of the alloy decreases by less than 10% after heat exposure at 400℃ for 1h, and by less than 20% after heat exposure at 600℃ for 1h. The performance of traditional heat-resistant aluminum alloys such as Al-Si and Al-Cu can drop by more than 50% when exposed to heat at 300℃ for 24h. Therefore, AlFeCoNi alloy is more heat-resistant and stable than traditional heat-resistant aluminum alloys.

[0042] The aluminum-iron-cobalt-nickel-scandium-zirconium-vanadium high temperature heat exposure resistant aluminum alloy prepared in step (6) is composed of: 1.0% iron, 1.0% cobalt, 1.0% nickel, 0.2% scandium, 0.2% zirconium, 0.4% vanadium, and the rest is aluminum. The alloy is based on the aluminum-iron-cobalt-nickel eutectic alloy, and after adding microalloying elements scandium, zirconium, and vanadium to the alloy, the hardness and high temperature heat resistance stability of the alloy can be significantly improved ( Figure 1 c).

[0043] Example 2

[0044] This embodiment provides a method for preparing an aluminum alloy with excellent creep deformation resistance, specifically a method for preparing an aluminum-iron-cobalt-nickel-scandium-titanium-vanadium-zirconium alloy, comprising the following steps:

[0045] (1) Weigh aluminum and various master alloys according to the following proportions: 63.0% high-purity aluminum, 5.0% aluminum-iron master alloy (Al-20Fe), 10.0% aluminum-cobalt master alloy (Al-10Co), 10.0% aluminum-nickel master alloy (Al-10Ni), 10.0% aluminum-scandium master alloy (Al-2Sc), 10.0% aluminum-titanium master alloy (Al-10Ti), 1% aluminum-vanadium master alloy (Al-10V), and 2% aluminum-zirconium master alloy (Al-10Zr);

[0046] (2) After pure aluminum is melted at 750°C, each master alloy is added and melted at 850°C and kept at high temperature. After the master alloy is fully melted, it is refined and degassed at 760°C;

[0047] (3) The above melt is directly cast into an ingot.

[0048] The composition of the aluminum-iron-cobalt-nickel-scandium-titanium-vanadium-zirconium creep-resistant eutectic aluminum alloy prepared in step (3) is: 1.0% iron, 1.0% cobalt, 1.0% nickel, 0.2% scandium, 0.1% titanium, 0.1% vanadium, 0.2% zirconium, and the rest is aluminum. After the addition of Sc, Ti, V, and Zr elements, the creep properties of the eutectic alloy at 400°C are significantly improved, and it has better creep performance than other heat-resistant alloys. Microalloying elements effectively reduce the creep rate of the eutectic alloy at 400°C by forming precipitated phases in the matrix to hinder dislocation movement, and precipitating at the eutectic phase interface to enhance the eutectic phase transfer stress. Comparison of the creep performance of the series of alloys at 400°C ( Figure 2 ), the eutectic alloy provided by the present invention has better creep resistance.

[0049] Example 3

[0050] This embodiment provides a method for preparing an aluminum alloy having superior creep deformation resistance and maintaining stable mechanical properties when exposed to high temperature for a long time, specifically, preparing an aluminum-iron-cobalt-nickel-scandium-titanium-vanadium-zirconium-manganese alloy, comprising the following steps:

[0051] (1) Aluminum and various master alloys are weighed in the following proportions: 55.0% high-purity aluminum, 5% aluminum-iron master alloy (Al-20Fe), 10% aluminum-cobalt master alloy (Al-10Co), 10% aluminum-nickel master alloy (Al-10Ni), 10% aluminum-scandium master alloy (Al-2Sc), 2% aluminum-titanium master alloy (Al-10Ti), 2% aluminum-vanadium master alloy (Al-10V), 1.0% aluminum-zirconium master alloy (Al-10Zr), and 5.0% aluminum-manganese master alloy (Al-10Mn).

[0052] (2) After pure aluminum is melted at 750°C, each master alloy is added and melted at 850°C and kept at high temperature. After the master alloy is fully melted, it is refined and degassed at 760°C.

[0053] (3) The above melt is directly cast into an ingot.

[0054] The prepared aluminum-iron-cobalt-nickel-scandium-titanium-vanadium-zirconium-manganese high temperature heat exposure resistant aluminum alloy has a composition of: 1% iron, 1% cobalt, 1% nickel, 0.2% scandium, 0.2% titanium, 0.2% vanadium, 0.1% zirconium, 0.5% manganese, and the rest is aluminum.

[0055] The addition of Zr can improve the heat resistance stability of the eutectic alloy at 400°C. However, excessive addition of Zr will significantly refine the grains and deteriorate the high-temperature performance of the alloy. This embodiment preferably uses microalloying components to reduce the zirconium content and inhibit the grain refinement effect caused by this element. At the same time, elements such as titanium, vanadium, and manganese are introduced to enhance the precipitation strengthening and solid solution strengthening effects. After component optimization, while improving the thermal exposure stability of the eutectic alloy, the high-temperature mechanical properties of the alloy are guaranteed. The alloy has more superior creep resistance such as Figure 2 As shown. Among them, the heat-resistant and stable Al 3 (Sc, Zr, Ti, V) can interact with dislocations to pin them and reduce the deformation rate of the eutectic matrix. At the same time, the dissolved Mn element can form gas masses with dislocations to reduce the dislocation movement rate. In summary, the multi-scale organizational component design can effectively improve the creep resistance.

[0056] In addition, the tensile performance test result of the alloy at 300°C was 91.2MPa. After heat exposure at 400°C for 100h, the tensile performance of the alloy at 300°C was tested again and was 83.1MPa. The alloy performance decreased by 8.9%. In comparison, after Al-6.5Cu-0.6Mn-0.5Fe-xSi alloy was heat exposed at 300°C for 100h, the tensile performance of the alloy at 300°C decreased by about 11% to 43.1%; after Al-Si-Cu-Mn-Fe alloy was heat exposed at 300°C for 100h, the tensile performance of the alloy at 300°C decreased by about 44.6% to 46.7%. In summary, the high-temperature resistant eutectic alloy provided by the present invention has good potential for high-temperature applications.

[0057] This specific implementation is only an explanation of the present invention, not a limitation of the present invention. Any changes made by those skilled in the art after reading the specification of the present invention will be protected by the patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A new type of high temperature resistant eutectic aluminum alloy, characterized by: The composition includes the following components by mass percentage: aluminum 90%-97%, iron 1-3.5%, cobalt 1-3.5%, nickel 1-3.5%, scandium 0-0.5%, titanium 0-0.5%, vanadium 0-0.5%, zirconium 0-0.5%, and manganese 0-1.0%.

2. The novel high temperature resistant eutectic aluminum alloy according to claim 1, characterized in that: The mass ratio of iron, cobalt and nickel is 1:1:

1.

3. The novel high temperature resistant eutectic aluminum alloy according to claim 1, characterized in that: Its composition includes aluminum, iron, cobalt, nickel, scandium, vanadium and zirconium.

4. The novel high temperature resistant eutectic aluminum alloy according to claim 1, characterized in that: Its composition includes aluminum, iron, cobalt, nickel, scandium, titanium, vanadium and zirconium.

5. The novel high temperature resistant eutectic aluminum alloy according to claim 1, characterized in that: Its components include aluminum, iron, cobalt, nickel, scandium, titanium, vanadium, zirconium and manganese.

6. The method for preparing the novel high temperature resistant eutectic aluminum alloy according to claim 1, characterized in that: The following steps are involved: S1. Weigh pure aluminum and various master alloys respectively; S2. Place pure aluminum into a crucible and heat it to melt; S3. After pure aluminum is melted, aluminum-iron, aluminum-cobalt and aluminum-nickel master alloys are added, and aluminum-scandium, aluminum-titanium, aluminum-vanadium, aluminum-zirconium and aluminum-manganese master alloys are selectively added, melted at high temperature and kept warm; S4. Refining and degassing; S5. The aluminum alloy melt that has completed the above treatment is subjected to forming processing.

7. The method for preparing the novel high temperature resistant eutectic aluminum alloy according to claim 6, characterized in that: In step S1, the mass percentage of each raw material is: pure aluminum 0-75.0%, aluminum-iron master alloy 5.0-17.5%, aluminum-cobalt master alloy 10.0-35.0%, aluminum-nickel master alloy 10.0-35.0%, aluminum-scandium master alloy 0.0-25.0%, aluminum-titanium master alloy 0.0-5.0%, aluminum-vanadium master alloy 0.0-5.0%, aluminum-zirconium master alloy 0.0-5.0%, aluminum-manganese master alloy 0.0-10.0%.

8. The method for preparing the novel high temperature resistant eutectic aluminum alloy according to claim 6, characterized in that: In step S2, the melting temperature is 700°C-1000°C.

9. The method for preparing the novel high temperature resistant eutectic aluminum alloy according to claim 6, characterized in that: In step S3, the high temperature melting and heat preservation temperature is higher than the melting temperature in step S2 by 0-200°C.

10. The method for preparing the novel high temperature resistant eutectic aluminum alloy according to claim 6, characterized in that: In step S4, the refining and degassing temperature is lower than the holding temperature in step S3 by 0-100°C.

11. The method for preparing the novel high temperature resistant eutectic aluminum alloy according to claim 6, characterized in that: In step S5, the melt is cast into an ingot or made into a wire by pouring or continuous casting and rolling.

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