CN114934206B - Multi-element aluminide reinforced aluminum-based composite material and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of metal matrix composite materials, and discloses a multi-element aluminide reinforced aluminum matrix composite material and its preparation method and application. The multi-component aluminide reinforcement phase contains five or more main elements, has high strength and high temperature thermal stability, and has high bonding strength with the aluminum matrix. The preparation process of the multi-element aluminide-reinforced aluminum-based composite material is simple, and it is obtained by synergistic in-situ diffusion of multi-element high-entropy alloy crucibles in pure aluminum or aluminum alloy metal liquids. At the same time, by applying mechanical stirring, the uniform distribution of elements is accelerated. and diffusion speed, the preparation efficiency is greatly increased. The reinforcing phase of the multi-element aluminide-reinforced aluminum matrix composite material is mostly distributed in the form of ultra-fine thin strips and short rods in the aluminum matrix, and its volume ratio can reach 7.7%. It has excellent mechanical properties at room temperature and high temperature, and has low density. , good thermal stability and corrosion resistance, it can be used in aerospace, automobile manufacturing and other fields.

Description

A kind of multi-element aluminide reinforced aluminum matrix composite material and its preparation method and application

technical field

The invention belongs to the technical field of metal-matrix composite materials, and in particular relates to a high-strength, high-plastic multi-component aluminide-reinforced aluminum-matrix composite material and its preparation method and application.

Background technique

With the continuous improvement of industry requirements for material performance, the performance of a single material has been difficult to meet the demand. For example, in applications such as automotive pistons, brake discs, and aircraft landing gear, materials need to maintain good mechanical properties in high temperature environments. Good abrasion resistance is required. The emergence of composite materials has solved the above problems well. By adjusting the components and contents of composite materials, the advantages of each component can be combined, thereby improving the comprehensive performance of materials and obtaining multifunctional materials. Aluminum alloy has the characteristics of low density, good processing performance, high specific strength, excellent thermal conductivity and corrosion resistance, and is widely used in aerospace, marine industry, transportation and other fields. Combining aluminum alloy with some reinforcements can retain the advantages of low density, good heat transfer and corrosion resistance of aluminum alloy, while enhancing the strength, wear resistance and thermal stability of the material.

Common reinforcements for aluminum matrix composites include SiC, graphene, intermetallic compounds, etc. Intermetallic compounds have the advantages of high strength, high modulus, high melting point, and good thermal stability, and have great application prospects in the field of high-temperature structural materials. However, intermetallic compounds have poor fracture toughness, are prone to brittle fracture, and have low ductility, which is not conducive to further processing. By adding intermetallic compounds to the aluminum matrix, the obtained aluminum matrix composite combines the advantages of aluminum alloy and intermetallic compounds, which is not only easy to process, low density, but also maintains high strength and creep resistance at high temperatures. In order to obtain high strength and high plasticity, and to eliminate the phenomenon of plasticity reduction caused by the introduction of intermetallic compounds, the present invention proposes a multi-element aluminide reinforced aluminum matrix composite material and provides a preparation method thereof.

Contents of the invention

In order to overcome the shortcomings and deficiencies in the prior art, the primary purpose of the present invention is to provide a multi-aluminide reinforced aluminum matrix composite material with light weight, good thermal stability and high mechanical strength.

Another object of the present invention is to provide a method for preparing the above-mentioned multi-component aluminide-reinforced aluminum-matrix composite material, which is the in-situ diffusion method of a diffusion couple.

Another object of the present invention is to provide an application of the above-mentioned multi-element aluminide reinforced aluminum matrix composite material.

The object of the present invention is achieved through the following technical solutions:

A multi-element aluminide-reinforced aluminum matrix composite material, the composite material is composed of multi-element aluminides of the reinforcing phase and a matrix; the matrix is pure Al or an Al alloy; the multi-element aluminide contains Al elements, and Co, Cr, Fe , Ni, Mn and Cu in more than four elements.

The preparation method of the above-mentioned multi-element aluminide reinforced aluminum matrix composite material comprises the following steps:

(1) Prepare a high-entropy alloy crucible ingot, the inner height of the crucible is h mm, the inner diameter is dmm, the thickness of the crucible is 10-50mm, and the composition of the high-entropy alloy crucible ingot is Co, Cr, Fe, Ni, Mn and Cu Four or more elements in the element are mixed according to the equiatomic ratio;

(2) Place the high-entropy alloy crucible ingot in a horse boiling furnace for homogeneous annealing, heat it to 1000-1200°C at a heating rate of 10°C/min, and keep it warm for 2 to 4 hours. The cooling rate is reduced to 400°C, and then cooled to room temperature with the furnace;

(3) Milling the inner surface of the high-entropy alloy crucible ingot by machining to remove the oxide film on the inner surface, the surface roughness is Ra12.5 and below; then use alcohol to clean and air-dry for later use;

(4) Remelt pure Al or Al alloy and cast it into a graphite crucible with a diameter of (d-2) mm to obtain a pure Al rod or aluminum alloy rod with a length of (h+3) mm and above, and ultrasonically Clean the surface of the bar with alcohol to remove water vapor, oil stains and oxide layer on the surface, and air dry for later use;

(5) Put the rod obtained in step (4) into the high-entropy alloy crucible ingot obtained in step (3), and use a press to force the part of the rod higher than the surface of the high-entropy alloy crucible ingot into the high-entropy alloy In the crucible ingot, a tightly combined high-entropy alloy/pure Al diffusion couple or high-entropy alloy/aluminum alloy diffusion couple is obtained;

(6) Put the prepared high-entropy alloy/pure Al diffusion couple or high-entropy alloy/aluminum alloy diffusion couple into a heat treatment furnace and heat it to 680-700°C at a heating rate of 10°C/min, and keep it warm for 2-6 hours; In the heat preservation process, mechanical stirring is applied to promote the synergistic diffusion and uniformity of distribution of multi-elements;

(7) After the heat preservation stage is over, the scum on the surface of the molten aluminum is removed, the molten aluminum is cast into a steel mold, and air-cooled to room temperature to obtain a multi-component aluminide-reinforced aluminum matrix composite.

The high-entropy alloy crucible casting ingot in step (1) is an equiatomic ratio high-entropy alloy CoCrFeMnNi, CoCrFeNi, or CoCrCuFeNi.

The high-entropy alloy crucible ingot in step (1) is obtained by machining the high-entropy alloy ingot, or by casting directly.

The sources of the high-entropy alloy ingot in step (1) and pure Al or Al alloy in step (4) are not particularly limited, and can be prepared according to methods well known to those skilled in the art, or can be commercially available products.

Al, Co, Cr, Fe, Ni, Mn or Cu used in the preparation process of the high-entropy alloy crucible ingot in step (1) are pure raw materials with a purity of 99.9 wt%.

The heating in step (2) is heating to 1000° C.; the time for keeping the heat is 4 hours.

The heating in step (6) is to heat to 680°C.

The application of mechanical stirring in step (6) is in the form of stirring in the conventional metal smelting process. The motor drives the stirring rod, and the other end of the stirring rod is connected to the turbine; the surfaces of the stirring rod and the turbine are coated with zirconia coating.

The application of the above-mentioned multi-component aluminide reinforced aluminum matrix composite material in the fields of aerospace and automobile manufacturing.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The more commonly used aluminum matrix composite material preparation method is the powder sintering method at present, but this type of method can only prepare small-sized workpieces, which is greatly restricted in industrial applications, and the preparation method provided by the present invention can prepare Large size workpieces meet the needs of industrial applications.

(2) The method used in the present invention belongs to the liquid diffusion synthesis method, and the current commonly used liquid synthesis method to prepare aluminum-based composite materials is to add reinforcement particles after melting aluminum, and then make the particles evenly distributed by stirring to form aluminum-based composite materials, However, this kind of method needs to process the reinforcement into granular first, and the particle distribution is not uniform, so it is easy to agglomerate. The present invention is based on the principle of in-situ precipitation of the second phase after element diffusion to form a supersaturated solid solution. The reinforcement is processed into particles, and the step of adding reinforcement particles to the aluminum liquid is also reduced during the preparation process, which simplifies the preparation process, and the precipitated phase of the prepared alloy is small and evenly distributed.

(3) The high-entropy alloy crucible in the preparation method of the present invention can be reused, which can effectively improve the utilization rate of materials, reduce waste of resources, and save costs.

(4) Compared with the aluminum matrix, the performance of the aluminum-based composite material prepared by the present invention is greatly improved, wherein the hardness is increased by nearly 100%, the yield strength is increased by nearly 100%-400%, and the elongation is close to the same as that of the aluminum matrix. It still maintains good plasticity and toughness; multi-element aluminide has high binding energy and thermal stability, which improves the usable temperature of aluminum alloy.

Description of drawings

Fig. 1 is a scanning electron micrograph of the multi-component aluminide reinforced aluminum matrix composite material prepared in Example 1 of the present invention.

Fig. 2 is an X-ray diffraction pattern of the multi-element aluminide reinforced aluminum matrix composite material prepared in Example 1 of the present invention.

Fig. 3 is the energy spectrum analysis result of the multi-element aluminide reinforced aluminum matrix composite material prepared in Example 1 of the present invention.

Fig. 4 is an engineering stress-strain curve measured by compression of the multi-component aluminide reinforced aluminum matrix composite material prepared in Example 1 of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

Example 1:

(1) Prepare a CoCrFeMnNi high-entropy alloy crucible ingot, the crucible internal height is 60mm, the internal diameter is 40mm, the crucible thickness is 10mm, and the high-entropy alloy crucible ingot composition is CoCrFeMnNi of equiatomic ratio;

(2) Place the high-entropy alloy crucible ingot in step (1) in a horse boiling furnace for homogenization annealing, heat it to 1000°C at a heating rate of 10°C/min and keep it for 4 hours, and cool it at 3°C/min after the heat preservation The temperature was lowered to 400°C, and then cooled to room temperature with the furnace.

(3) Milling the inner surface of the high-entropy alloy crucible ingot by machining to remove the oxide film on the inner surface, the surface roughness is Ra12.5 and below; use alcohol to clean the crucible and air-dry it for later use;

(4) Remelt pure Al, cast it into a graphite crucible with a diameter of 38mm, obtain a rod with a length of 80mm, cut off the shrinkage cavity at the top, and the remaining rod length is 63mm, clean the surface with ultrasonic alcohol to remove water vapor, oil stains and Oxidized layer, air-dried for later use;

(5) Put the rod obtained in step (4) into the high-entropy alloy crucible obtained in step (3), and use a press to force the part of the rod higher than the surface of the high-entropy alloy crucible ingot into the high-entropy alloy crucible for casting In the ingot, there is no gap between the two, and a tightly combined CoCrFeMnNi high-entropy alloy/pure Al diffusion couple is obtained;

(6) Put the prepared CoCrFeMnNi high-entropy alloy/pure Al diffusion couple into a heat treatment furnace and heat it to 700°C at a heating rate of 10°C/min, and keep it warm for 4 hours; during the heat preservation process, apply mechanical stirring to promote multiple Coordinated diffusion and distribution uniformity of elements;

(7) After the heat preservation stage is over, the scum on the surface of the molten aluminum is removed, the molten aluminum is cast into a steel mold, and air-cooled to room temperature to obtain a multi-component aluminide-reinforced aluminum matrix composite of a certain size and shape.

The CoCrFeMnNi high-entropy alloy crucible ingot preparation process in step (1) involves Co, Cr, Fe, Ni, and Mn elements, all of which are pure raw materials with a purity of at least 99.9 wt%.

Example 2:

(1) Prepare a CoCrFeNi high-entropy alloy crucible ingot, the crucible internal height is 50mm, the internal diameter is 30mm, the crucible thickness is 10mm, and the high-entropy alloy crucible ingot composition is CoCrFeNi of equiatomic ratio;

(2) Place the high-entropy alloy crucible ingot in step (1) in a horse boiling furnace for homogenization annealing, heat it to 1000°C at a heating rate of 10°C/min and keep it for 4 hours, and cool it at 3°C/min after the heat preservation The temperature was lowered to 400°C, and then cooled to room temperature with the furnace.

(3) Milling the inner surface of the high-entropy alloy crucible ingot by machining to remove the oxide film on the inner surface, the surface roughness is Ra12.5 and below; use alcohol to clean the crucible and air-dry it for later use;

(4) Remelt pure Al and cast it into a graphite crucible with a diameter of 28mm to obtain a rod with a length of 70mm, cut off the shrinkage cavity at the top, and the remaining rod length is 53mm, clean the surface with ultrasonic alcohol to remove water vapor, oil stains and Oxidized layer, air-dried for later use;

(5) Put the rod obtained in step (4) into the high-entropy alloy crucible obtained in step (3), and use a press to force the part of the rod higher than the surface of the high-entropy alloy crucible ingot into the high-entropy alloy crucible for casting In the ingot, there is no gap between the two, and a tightly combined CoCrFeNi high-entropy alloy/pure Al diffusion couple is obtained;

(6) Put the prepared CoCrFeNi high-entropy alloy/pure Al diffusion couple into a heat treatment furnace and heat it to 680°C at a heating rate of 10°C/min, and keep it warm for 6 hours; during the heat preservation process, apply mechanical stirring to promote multiple Coordinated diffusion and distribution uniformity of elements;

(7) After the heat preservation stage is over, the scum on the surface of the molten aluminum is removed, the molten aluminum is cast into a steel mold, and air-cooled to room temperature to obtain a multi-component aluminide-reinforced aluminum matrix composite of a certain size and shape.

The CoCrFeNi high-entropy alloy crucible ingot preparation process mentioned in step (1) involves Co, Cr, Fe, and Ni elements all using pure raw materials with a purity of at least 99.9 wt%.

Fig. 1 is the scanning electron micrograph of the multi-component aluminide reinforced aluminum matrix composite material prepared in Example 1 of the present invention. It can be seen from Fig. 1 that the intermetallic compound reinforcement phase of the aluminum matrix composite material is mostly distributed in thin strips in the aluminum matrix. Using ImagePro The software makes statistics on 20 different positions of the sample, and the area ratio of the intermetallic compound phase is about 7.7%, while the standard deviation is 0.6%, indicating that the intermetallic compound phase is evenly distributed in the aluminum matrix.

Fig. 2 is the X-ray diffraction spectrum of the multi-element aluminide reinforced aluminum matrix composite material prepared in Example 1 of the present invention, it can be known from Fig. 2 that the phases existing in the aluminum matrix composite material are mainly divided into Al matrix and phase structure approximate Al ₉ Multinary intermetallic phase of _Co2 .

Figure 3 is the energy spectrum analysis result of the multi-element aluminide reinforced aluminum matrix composite material prepared in Example 1 of the present invention, from Figure 3 it can be known that the intermetallic compound in the aluminum matrix composite material is mainly composed of Al, Fe, Co, Ni , also contains a small amount of Cr and Mn elements, of which Al atoms account for about 83%, and the atomic ratio of Fe, Co, and Ni is close to 1:1:1. Combined with the X-ray diffraction pattern analysis in Figure 2, it is speculated that its intermetallic compound phase It is Al ₉ (FeCoNi) ₂ phase.

Fig. 4 is the engineering stress-strain curve measured by the compression of the multi-element aluminide reinforced aluminum matrix composite material prepared in Example 1 of the present invention. It can be known from Fig. 4 that the strain yield strength of the aluminum matrix composite material is 119.8Mpa, which does not pass The yield strength of the strengthened pure aluminum rod is 30.9Mpa, and its yield strength is increased by nearly 400%, while still maintaining a high elongation.

The Vickers hardness of the multi-element aluminide-reinforced aluminum matrix composite material prepared in Example 1 is HV49. Under the same test conditions and environment, the Vickers hardness of pure aluminum is HV25, and the hardness is increased by nearly 100%.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention , all should be equivalent replacement methods, and are all included in the protection scope of the present invention.

Claims (7)

1. A multi-element aluminide reinforced aluminum matrix composite is characterized in that: the composite material consists of a reinforced phase multi-element aluminide and a matrix; the substrate is pure Al or Al alloy; the multi-element aluminide contains Al element, co, cr, fe, ni and Mn;

the preparation method of the multi-element aluminide reinforced aluminum matrix composite material comprises the following operation steps:

(1) Preparing a high-entropy alloy crucible ingot, wherein the height of the inside of the crucible is h mm, the diameter of the inside of the crucible is d mm, the thickness of the crucible is 10-50mm, and the high-entropy alloy crucible ingot is prepared by mixing Co, cr, fe, ni and Mn according to equal atomic ratio;

(2) Placing the high-entropy alloy crucible cast ingot in a muffle furnace for homogenizing annealing, heating to 1000-1200 ℃ at a heating rate of 10 ℃/min, preserving heat for 2-4 hours, cooling to 400 ℃ at a cooling rate of 3 ℃/min after heat preservation, and then cooling to room temperature along with the furnace;

(3) Milling the inner surface of the high-entropy alloy crucible cast ingot by machining, and removing an oxide film on the inner surface, wherein the surface roughness is less than Ra12.5; then cleaning with alcohol and air drying for later use;

(4) Remelting pure Al or Al alloy, casting the pure Al or Al alloy into a graphite crucible with the diameter of (d-2) mm to obtain a pure Al bar or an aluminum alloy bar with the length of more than (h + 3) mm, cleaning the surface of the bar by ultrasonic alcohol, removing surface water vapor, oil stain and an oxide layer, and air-drying for later use;

(5) Putting the bar material obtained in the step (4) into the high-entropy alloy crucible ingot obtained in the step (3), and forcibly pressing the part of the bar material, which is higher than the surface of the high-entropy alloy crucible ingot, into the high-entropy alloy crucible ingot by using a press machine to obtain a tightly-combined high-entropy alloy/pure Al diffusion couple or a high-entropy alloy/aluminum alloy diffusion couple;

(6) Putting the prepared high-entropy alloy/pure Al diffusion couple or high-entropy alloy/aluminum alloy diffusion couple into a heat treatment furnace, heating to 680-700 ℃ at the heating rate of 10 ℃/min, and preserving heat for 2-6 hours; in the heat preservation process, mechanical stirring is applied to promote the synergistic diffusion and the distribution uniformity of multiple elements;

(7) And after the heat preservation stage is finished, removing dross on the surface of the aluminum liquid, casting the aluminum liquid into a steel mould, and air-cooling to room temperature to obtain the multi-element aluminide reinforced aluminum-based composite material.

2. The multi-aluminide reinforced aluminum-based composite material of claim 1, wherein: the high-entropy alloy crucible cast ingot in the step (1) is obtained by machining the high-entropy alloy cast ingot or directly casting the high-entropy alloy crucible cast ingot by a casting method.

3. The multi-aluminide reinforced aluminum-based composite material of claim 1, wherein: and (2) selecting pure raw materials with the purity of more than 99.9wt% for Al, co, cr, fe, ni or Mn used in the preparation process of the high-entropy alloy crucible ingot in the step (1).

4. The multi-aluminide reinforced aluminum-based composite material of claim 1, wherein: the heating of the step (2) is heating to 1000 ℃; the time for heat preservation was 4 hours.

5. The multi-aluminide reinforced aluminum-based composite material of claim 1, wherein: the heating in the step (6) is heating to 680 ℃.

6. The multi-aluminide reinforced aluminum-based composite material of claim 1, wherein: the mechanical stirring is applied in a stirring mode in the conventional metal smelting process, a motor drives a stirring rod, and the other end of the stirring rod is connected with a turbine; the surfaces of the stirring rod and the turbine are coated with zirconia coatings.

7. Use of the multi-aluminide reinforced aluminium-based composite material according to claim 1 in the fields of aerospace and automotive manufacturing.

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