Aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting and preparation method therefor

Abstract

An aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting and a preparation method therefor. The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting is prepared by means of a pressure casting or extruding casting process, and has the components of: 1.4-1.7 wt% of Fe, 0.5-1.0 wt% of Ni, 0.10-0.15% of Si, 0.08-0.15% of Mg, 0.015-0.020% of Ti, less than or equal to 0.05 wt% of Cu and the balance being aluminum and other inevitable trace impurity elements, wherein the content of each individual trace impurity element is less than or equal to 0.03 wt%, and the total amount of all trace impurity elements is less than or equal to 0.10 wt%. The prepared aluminum-iron-nickel-silicon-magnesium-titanium alloy material has good mechanical properties at room temperature and high temperatures in the as-cast state and excellent electrical conductivity, and has wide application prospects in the field of electric transportation components such as induction motor rotors.

Description

Aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting and preparation method thereof Technical Field

[0001] The present invention relates to the field of preparation of aluminum alloy materials, and specifically to an aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting with high conductivity, high temperature (>180°C) and high strength, and a preparation method thereof. Background Art

[0002] Aluminum alloys offer advantages such as low density, high specific strength, corrosion resistance, and excellent processability, making them widely used in a variety of fields, including automotive, machinery, and aerospace. Cast aluminum alloys are the most widely used. However, in certain medium- and high-temperature environments, such as automotive engines and induction motors, the strength of cast aluminum alloys decreases as operating temperatures rise, making them susceptible to deformation and fracture due to insufficient strength.

[0003] The high-temperature mechanical properties of aluminum alloys primarily depend on the stability of their microstructure at high temperatures. Currently, the primary strategy for improving the high-temperature mechanical properties of cast aluminum alloys is to introduce various alloying elements, such as copper, iron, nickel, and silicon, into the alloy. By manipulating the microstructure, these elements form thermally stable strengthening phases within the matrix, enhancing the pinning effect of relative dislocations and ultimately improving the alloy's high-temperature mechanical properties.

[0004] Pure aluminum has the best electrical conductivity among aluminum alloys. Aluminum's electrical conductivity is proportional to the electron's free path. Impurity scattering is a key factor influencing this path: the stronger the impurity scattering, the shorter the electron's free path. To improve the room-temperature and high-temperature mechanical properties of aluminum alloys, various alloying elements such as copper, iron, nickel, and silicon are introduced into cast aluminum alloys. This increases impurity scattering and reduces the alloy's electrical conductivity. For example, A356 alloy, the most widely used cast aluminum alloy, has an as-cast yield strength of 130 MPa, but its electrical conductivity is less than 40% IACS.

[0005] Induction motor rotor materials are required to be lightweight, highly conductive, and have good high-temperature strength. At the same time, for industrial applications, reducing material costs is of great significance. Therefore, in order to prepare cast aluminum alloys that combine high conductivity with good high-temperature yield strength, it is necessary to optimize the design and control of the types, contents, and microstructures of the alloying elements. Patent 201980053078.0 invents a high-yield strength (≥90MPa) and high-conductivity (≥48% IACS) aluminum alloy containing 4% to 6% nickel, with an iron content of 0.2% to 0.8%. However, nickel is expensive. Furthermore, when the patented aluminum alloy is selected within the lower limit of the iron content, the alloy preparation requires the use of industrial-pure aluminum, and recycled aluminum alloys cannot be used. Compared to using recycled aluminum alloys, the energy consumption of electrolytically preparing pure aluminum is approximately 20 times higher, and it also consumes alumina resources. Therefore, it is of great significance to develop cast aluminum alloys that can utilize recycled aluminum alloys, reduce costs, and have high conductivity and good high-temperature strength.

[0006] To obtain a cast aluminum alloy with good electrical conductivity and high-temperature strength, alloying elements must be added without significantly reducing the material's electrical conductivity and forming a strengthening phase that is stable at high temperatures. To be able to recycle aluminum alloys, a certain iron content is required, and some trace elements are acceptable. The Al3Fe phase is stable at high temperatures, and the addition of nickel forms a high-temperature stable Al9(Fe,Ni)2 phase. The presence of nickel enhances electron migration in this phase. Adding titanium can form (AlSi)3Ti particles at high temperatures, which have a coherent relationship with the aluminum matrix, promoting nucleation and grain refinement, thereby increasing the alloy's yield strength.

[0007] In response to the problem that the existing technology cannot achieve environmentally friendly and low-cost pressure casting or casting of aluminum alloys with high conductivity and high-temperature yield strength, the present invention designs and invents a cast aluminum-iron-nickel-silicon-magnesium-titanium alloy material with high conductivity and good yield strength at high temperatures, and the material can be prepared using recycled aluminum alloys.

[0008] Summary of the Invention

[0009] The present invention aims to provide an aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting and a preparation method thereof. The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting has good high-temperature mechanical properties and electrical conductivity, contains few precious metal elements, can be prepared using recycled aluminum alloy, and has low cost.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] On the one hand, the present invention provides an aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting, comprising the following elemental components: Fe 1.4-1.7wt%, Ni 0.5-1.0wt%, Si 0.10-0.15%, Mg 0.08-0.15%, Ti 0.015-0.020%, Cu ≤ 0.05wt%, and the remainder being aluminum and other inevitable trace impurity elements, wherein the content of a single element in the trace impurity elements is ≤ 0.03wt%, and the total amount of trace impurity elements is ≤ 0.10wt%.

[0012] Optionally, the above-mentioned aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting is prepared by industrial pure aluminum, AlNi master alloy, AlFe master alloy, and recycled 6061 alloy.

[0013] Optionally, the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting has a tensile strength of 150-180 MPa, a yield strength of 80-90 MPa, and an elongation of 6-14% at room temperature.

[0014] Optionally, the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting has a tensile strength of 120-170 MPa, a yield strength of 75-85 MPa, and an elongation of 7-18% under high temperature conditions of 180°C.

[0015] Optionally, the electrical conductivity of the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting is 47-53% IACS.

[0016] In another aspect, the present invention provides a method for preparing the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting, comprising the following steps:

[0017] (1) adding industrial pure aluminum ingot, recovered 6061 alloy, AlNi master alloy, and AlFe master alloy in sequence for smelting;

[0018] (2) After the alloy is completely melted, a refining agent is added for refining, an inert gas is introduced for degassing, and the slag on the surface of the melt is removed after standing;

[0019] (3) After the melt is cooled, the casting operation is carried out.

[0020] Optionally, the casting operation is pressure casting or extrusion casting.

[0021] The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting is prepared from industrial pure aluminum, recycled 6061 alloy, Al-Ni master alloy and AlFe master alloy.

[0022] Compared with the prior art, the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting provided by the present invention has higher high-temperature mechanical properties and electrical conductivity. The principle is as follows:

[0023] The present invention introduces appropriate Fe and Ni elements to form stable Al3Fe phases and Al9(Fe,Ni)2 phases in the alloy, thereby improving the high-temperature mechanical properties of the alloy. Due to the presence of Ni, the Al9(Fe,Ni)2 phase contributes to the electrical conductivity of the alloy. The Mg element is dissolved in the matrix during the pressure casting process, thereby improving the yield strength of the matrix. The Ti element forms Al3Ti or (AlSi)3Ti phases with Al and Si elements in the alloy, thereby promoting nucleation, refining grains, and improving the yield strength of the alloy.

[0024] Compared with existing high-conductivity and heat-resistant casting aluminum-nickel alloy materials, the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting of the present invention has the following outstanding advantages:

[0025] 1. The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting of the present invention has high room-temperature and high-temperature mechanical properties, as well as electrical conductivity, through controlled element content and microstructure. The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting of the present invention has an as-cast tensile strength of 150-180 MPa, a yield strength of 80-90 MPa, and an elongation of 6-14% at room temperature. At 180°C, the as-cast tensile strength can reach 120-170 MPa, a yield strength of 75-85 MPa, and an elongation of 7-18%. The room-temperature electrical conductivity can reach 47-53% IACS.

[0026] 2. The main alloying element in the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting of the present invention is iron, and it can be prepared using recycled aluminum alloy; the nickel content in the alloy material is 0.5-1.0wt%, which is much lower than other existing highly conductive and heat-resistant casting aluminum alloys; the room temperature and high temperature mechanical properties and electrical conductivity of the alloy of the present invention are comparable to those of existing highly conductive and heat-resistant casting aluminum alloys; the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting of the present invention has lower cost while ensuring mechanical properties and electrical conductivity.

[0027] 3. The solidification range of the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting of the present invention is 15-25°C, it has good fluidity and low thermal cracking tendency, and has a low content of alloy elements and a higher content of α-Al phase, so the alloy has higher electrical conductivity and elongation.

[0028] 4. The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting of the present invention is prepared by recycling aluminum alloy, introducing trace amounts of elements such as magnesium and copper, and utilizing the high solidification rate of the pressure casting process to achieve solid solution of elements such as magnesium and copper in the α-Al matrix, thereby improving the yield strength of the alloy material.

[0029] 4. The high-temperature mechanical properties and electrical conductivity of the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting of the present invention in the cast state can meet the mechanical and electrical conductivity requirements of components such as induction motor rotors. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 is a SEM image of an alloy of a specific embodiment. DETAILED DESCRIPTION

[0031] In order to make the technical solution of the present invention clearer, the present invention is further described below through examples. It should be noted that the implementation methods of the present invention are not limited to these.

[0032] Example 1

[0033] Step 1: Ingredients

[0034] Table 1

[0035] Step 2: Melting

[0036] First, put industrial pure aluminum and recycled 6061 alloy into the melting furnace, then slowly raise the furnace temperature to 750℃, add Al-10Ni master alloy after it is completely melted, stir it evenly after melting, and then add Al-5Fe master alloy. After the alloy is completely melted, keep it warm for 30 minutes, then add commercial solid refining agent to the aluminum liquid at a ratio of 0.4%, remove the scum on the surface of the melt, and finally introduce high-purity argon gas for 15 minutes to remove the hydrogen contained in the melt and make the melt homogenized. After standing for 10 minutes, scrape off the surface scum.

[0037] Step 3: Pressure Casting

[0038] The mold is pre-sprayed with a release agent and then preheated to 200°C. The temperature of the molten aluminum is controlled between 720°C and 740°C before pressure casting.

[0039] The alloy composition is: Fe1.4%, Ni0.5%, Si0.13%, Mg0.1%, Ti0.015%, Cu0.038%, other elements ≤0.100%, and the rest is aluminum.

[0040] The mechanical properties of the alloy material at room temperature and 180℃, as well as the room temperature electrical conductivity are shown in Table 2.

[0041] Table 2 Mechanical properties and electrical conductivity of the alloy in Example 1

[0042] Example 2

[0043] Step 1: Ingredients

[0044] Table 3

[0045] Step 2: Melting

[0046] First, put industrial pure aluminum and recycled 6061 alloy into the melting furnace, then slowly raise the furnace temperature to 750℃, add Al-10Ni master alloy after it is completely melted, stir it evenly after melting, and then add Al-5Fe master alloy in sequence. After the alloy is completely melted, keep it warm for 30 minutes, then add commercial solid refining agent to the aluminum liquid at a ratio of 0.4%, remove the scum on the surface of the melt, and finally pass high-purity argon gas for 10 minutes to remove the hydrogen contained in the melt and make the melt homogenized. After standing for 10 minutes, scrape off the surface scum.

[0047] Step 3: Pressure Casting

[0048] The mold is pre-sprayed with release agent and preheated to 180°C. The temperature of the molten aluminum is controlled between 710°C and 730°C before pressure casting.

[0049] The composition of the alloy material obtained through the above steps is:

[0050] The alloy composition is: Fe1.68%, Ni0.9%, Si0.129%, Mg0.136%, Ti0.02%, Cu0.044%, other elements ≤0.100%, and the rest is aluminum.

[0051] The mechanical properties of the alloy material at room temperature and 180℃, as well as the room temperature electrical conductivity are shown in Table 4.

[0052] Table 4 Mechanical properties and electrical conductivity of the alloy of Example 2

Claims

1. A casting aluminum-iron-nickel-silicon-magnesium-titanium alloy material, characterized in that: The invention comprises the following element components: Fe 1.4-1.7wt%, Ni 0.5-1.0wt%, Si 0.10-0.15%, Mg 0.08-0.15%, Ti 0.015-0.020%, Cu ≤ 0.05wt%, and the remainder is aluminum and other inevitable trace impurity elements, the content of a single element in the trace impurity elements is ≤ 0.03wt%, and the total amount of the trace impurity elements is ≤ 0.10wt%.

2. The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting according to claim 1, characterized in that: The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting is prepared by industrial pure aluminum, AlNi master alloy, AlFe master alloy and recycled 6061 alloy.

3. The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting according to claim 1 or 2, characterized in that: The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting has a tensile strength of 150-180 MPa, a yield strength of 80-90 MPa and an elongation of 6-14% under room temperature conditions.

4. The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting according to claim 1 or 2, characterized in that: The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting has a tensile strength of 120-170 MPa, a yield strength of 75-85 MPa and an elongation of 7-18% under a high temperature condition of 180°C.

5. The aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting according to claim 1 or 2, characterized in that: The electrical conductivity of the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting is 47-53% IACS.

6. The method for preparing the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting according to claim 1, characterized in that: The following steps are involved: (1) adding industrial pure aluminum ingot, recovered 6061 alloy, AlNi master alloy, and AlFe master alloy in sequence for smelting; (2) After the alloy is completely melted, a refining agent is added for refining, an inert gas is introduced for degassing, and the slag on the surface of the melt is removed after standing; (3) After the melt is cooled, the casting operation is carried out.

7. The method for preparing the aluminum-iron-nickel-silicon-magnesium-titanium alloy material for casting according to claim 6, characterized in that: The casting operation is pressure casting or squeeze casting.

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