High-strength, high-toughness and high-entropy alloy composite material and preparation method thereof

Abstract

The invention relates to the field of high-entropy alloy materials, in particular to a high-strength high-toughness high-entropy alloy composite material and a preparation method thereof. The preparation method of the high-strength, high-toughness and high-entropy alloy composite material comprises the following steps that A, under the protective gas atmosphere, CoCrFeNi powder and AlxCoCrFeNi powder are alternately deposited through a directional energy deposition process, and a composite layer set is formed; wherein x is equal to 0.2, 0.4, 0.6, 0.8 or 1.0; and B) carrying out heat treatment on the composite layer group at 700-1100 DEG C to obtain the high-strength, high-toughness and high-entropy alloy composite material. According to the high-strength, high-toughness and high-entropy alloy composite material, the high plasticity of CoCrFeNi and the high strength of AlxCoCrFeNi are well exerted, and the high-strength and high-toughness material performance is obtained through regulation and control of a layered structure, so that the high-strength, high-toughness and high-entropy alloy composite material has wide application potential in the fields of aerospace, nuclear power, deep sea equipment and the like.

Description

Technical Field

[0001] The present invention relates to the field of high entropy alloy materials, and in particular to a high-strength and high-toughness high entropy alloy composite material and a preparation method thereof. Background Art

[0002] With the increasing demand for lightweight, high-strength, and high-toughness materials in aerospace, defense, and high-end manufacturing, traditional metal materials are no longer able to meet the service requirements in certain extreme environments. In recent years, the emergence of high-entropy alloys (HEAs) has provided new research perspectives and design concepts in materials science. HEAs are composed of multiple metallic elements in equimolar or near-equimolar ratios. Their notable characteristics include the high entropy effect, delayed diffusion, severe lattice distortion, and the "cocktail effect," which give them excellent comprehensive properties such as high strength, high plasticity, good corrosion resistance, and resistance to high-temperature softening.

[0003] In the research and development of alloy materials, it remains a technical challenge to simultaneously meet the two seemingly contradictory properties of high strength and high toughness. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a high-strength, high-toughness, high-entropy alloy composite material and a preparation method thereof. The high-strength, high-toughness, high-entropy alloy composite material prepared by the present invention can well meet the requirements of high strength and high toughness.

[0005] Directed Energy Deposition (DED) is a typical metal additive manufacturing technology. Its ability to build complex geometric structures "point by point and layer by layer" in three-dimensional space has made it widely used in the manufacture and repair of high-performance alloys. Compared to other additive manufacturing technologies such as selective laser melting (SLM) and electron beam melting (EBM), DED can deposit material directly on the surface of existing parts, enabling in-situ repair and multi-material printing.

[0006] However, additive manufacturing often faces challenges such as high thermal stress, coarse grains, porosity, and cracks. In DED, parameters such as laser power, scanning speed, powder flow rate, and cooling rate directly impact the quality and microstructure of the deposited layer. Furthermore, the multi-principal component design of high-entropy alloys further complicates their solidification behavior.

[0007] At present, research on DED additive manufacturing of high-entropy alloys mostly focuses on the process parameter optimization and microstructure and performance regulation of a single high-entropy alloy. However, the selection of two high-entropy alloys that can work well with each other, as well as how to achieve "layer-by-layer" metallurgical bonding, composition transition control, and thermal stress elimination of these two high-entropy alloys, remain core technical challenges in multi-material additive manufacturing.

[0008] The present invention provides a method for preparing a high-strength, high-toughness, high-entropy alloy composite material, comprising the following steps:

[0009] A) In a protective gas atmosphere, CoCrFeNi powder and Al x CoCrFeNi powders are alternately deposited by a directed energy deposition process to form a composite layer group;

[0010] Wherein, x=0.2, 0.4, 0.6, 0.8 or 1.0;

[0011] B) heat treating the composite layer group at 700° C. to 1100° C. to obtain a high-strength, high-toughness, high-entropy alloy composite material.

[0012] Preferably, the parameters of the directed energy deposition include:

[0013] The laser power is 800-1800W, the scanning speed is 6-15mm / s, the laser beam spot diameter is 3mm, and the transfer speed is 0.5-6.0rpm.

[0014] Preferably, the particle size of the CoCrFeNi powder is 45 to 150 μm.

[0015] Preferably, the Al x The particle size of the CoCrFeNi powder is 45 to 150 μm.

[0016] Preferably, the protector is argon gas.

[0017] Preferably, the thickness of each layer in the composite layer group is 0.05-0.1 mm.

[0018] Preferably, the heat treatment time is 4 to 6 hours.

[0019] Preferably, after the heat treatment, the method further comprises cooling.

[0020] The present invention also provides a high-strength, high-toughness, high-entropy alloy composite material prepared by the preparation method described above.

[0021] The present invention provides a method for preparing a high-strength, high-toughness, high-entropy alloy composite material, comprising the following steps: A) alternately depositing CoCrFeNi powder and AlxCoCrFeNi powder using a directed energy deposition process under a protective gas atmosphere to form a composite layer group; wherein x = 0.2, 0.4, 0.6, 0.8, or 1.0; and B) heat treating the composite layer group at 700°C to 1100°C to obtain a high-strength, high-toughness, high-entropy alloy composite material. The high-strength, high-toughness, high-entropy alloy composite material of the present invention effectively utilizes the high plasticity of CoCrFeNi and the high strength of AlxCoCrFeNi. By regulating the layered structure, it achieves high strength and toughness, making it have broad application potential in aerospace, nuclear power, deep-sea equipment, and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a SEM image of the high-strength, high-toughness, high-entropy alloy composite material prepared in Example 1 of the present invention;

[0023] Figure 2 This is a phase structure diagram of the high-strength, high-toughness, high-entropy alloy composite material prepared in Example 1 of the present invention;

[0024] Figure 3 A physical picture of the CoCrFeNi alloy and the high-strength, high-toughness, high-entropy alloy composite material of Example 1 of the present invention;

[0025] Figure 4 This is a tensile performance diagram of the high-strength, high-toughness, high-entropy alloy composite material prepared in Example 1 of the present invention;

[0026] Figure 5 This is a graph showing the tensile properties of the composite material prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] The present invention provides a method for preparing a high-strength, high-toughness, high-entropy alloy composite material, comprising the following steps:

[0029] A) In a protective gas atmosphere, CoCrFeNi powder and Al x CoCrFeNi powders are alternately deposited by a directed energy deposition process to form a composite layer group;

[0030] Wherein, x=0.2, 0.4, 0.6, 0.8 or 1.0;

[0031] B) heat treating the composite layer group at 700° C. to 1100° C. to obtain a high-strength, high-toughness, high-entropy alloy composite material.

[0032] Regarding step A):

[0033] In a protective gas atmosphere, CoCrFeNi powder and Al x CoCrFeNi powders are alternately deposited by a directed energy deposition process to form a composite layer group;

[0034] Wherein, x=0.2, 0.4, 0.6, 0.8 or 1.0.

[0035] In some embodiments of the present invention, the protective gas is argon.

[0036] The present invention is to the CoCrFeNi powder and Al x There is no special restriction on the source of CoCrFeNi powder, which can be purchased from the market or homemade. For example, the CoCrFeNi powder can be made from CoCrFeNi alloy material by gas atomization or mechanical pulverization in an argon atmosphere. The particle size of the CoCrFeNi powder is 45 to 150 μm to ensure stable powder feeding and uniform deposition during the DED additive manufacturing process. x CoCrFeNi powder can be made of Al x The CoCrFeNi alloy material is prepared by gas atomization or mechanical pulverization in an argon atmosphere. x The particle size of the CoCrFeNi powder is 45 to 150 μm to ensure stable powder feeding and uniform deposition during the DED additive manufacturing process.

[0037] In some embodiments of the present invention, the parameters of the directed energy deposition include:

[0038] The laser power is 800-1800W, the scanning speed is 6-15mm / s, the laser beam spot diameter is 3mm, and the transfer speed is 0.5-6.0rpm.

[0039] The directed energy deposition uses a directed energy deposition laser additive manufacturing device from Han's Laser, configured with a 500W to 3000W laser, such as a 3000W laser.

[0040] The directed energy deposition process of the present invention can avoid common additive manufacturing defects such as porosity, lack of fusion and cracks, so that the material has a dense microstructure and excellent interface bonding strength.

[0041] The CoCrFeNi layer and the Al layer were deposited alternately by the directed energy deposition process. xIn some embodiments of the present invention, the thickness of each layer in the composite layer group is 0.05-0.1 mm.

[0042] Regarding step B):

[0043] The composite layer group is heat-treated at 700° C. to 1100° C. to obtain a high-strength, high-toughness, high-entropy alloy composite material.

[0044] In some embodiments of the present invention, the heat treatment temperature is 700° C., the heat treatment time is 4 to 6 hours, for example, 6 hours, and the heat treatment process is completed in a box-type resistance furnace (muffle furnace).

[0045] After the heat treatment, the process further includes cooling, specifically, naturally cooling to room temperature.

[0046] After heat treatment, the CoCrFeNi layer and Al x The columnar grains in the CoCrFeNi layer gradually transform into equiaxed grains and x Nanoscale Al-rich strengthening phases precipitate in the CoCrFeNi layer. These precipitated phases can hinder dislocation slip and crack propagation, significantly improving the strength and toughness of the material. The yield strength and hardness of the material are increased by more than 20%, while anisotropy is significantly reduced, thereby improving the material's long-term service stability and adaptability to high-temperature environments.

[0047] The present invention also provides a high-strength, high-toughness, high-entropy alloy composite material prepared by the preparation method described above.

[0048] The high strength, high toughness and high entropy alloy composite material of the present invention makes good use of the high plasticity of CoCrFeNi and the advantages of Al x The high strength of CoCrFeNi is achieved through the regulation of layered structure, which results in high-strength and high-toughness material properties, and exhibits excellent resistance to crack growth under high stress and high impact load conditions.

[0049] Compared to traditional single high-entropy alloys, the composite layered structure of this invention exhibits superior crack growth resistance and fatigue resistance under tension, compression, and impact loads, with a well-matched yield strength and ductility. This structure effectively inhibits crack initiation and propagation under high stress and impact loads, and its high strength and toughness offer broad potential for applications in aerospace, nuclear power, and deep-sea equipment.

[0050] In order to further illustrate the present invention, a high-strength, high-toughness, high-entropy alloy composite material and a preparation method thereof provided by the present invention are described in detail below in conjunction with examples, but it should not be understood as limiting the scope of protection of the present invention.

[0051] In the examples, directed energy deposition utilizes a Han's Laser HLC-30 laser cladding system. The system primarily consists of an Etelux Lab unidirectional glove box, a Fanuc R2000i six-axis industrial robot, a Han's Laser 3000W fiber laser (laser wavelength approximately 1076nm), and a four-way coaxial powder feeder. During cladding, the glove box maintains an air pressure of 1.0 to 3.0 mbar and continuously flows with 99.999% pure argon gas, with a water and oxygen content below 10 ppm.

[0052] The particle size of the CoCrFeNi powder used in the embodiment is 45-150 μm, and the Al x The particle size of CoCrFeNi powder is 45-150 μm, and all of them come from Chengdu Kewan Company.

[0053] Example 1

[0054] Preparation of high-strength, high-toughness, high-entropy alloy composites:

[0055] 1) Under an argon atmosphere, CoCrFeNi powder and AlCoCrFeNi powder are alternately deposited by a directed energy deposition process to form a composite layer group;

[0056] The parameters of the directed energy deposition are:

[0057] The laser power was 1500 W, the scanning speed was 10 mm / s, the laser beam spot diameter was 3 mm, and the transfer speed was 3.0 rpm;

[0058] The composite layer group is a layered structure of alternating CoCrFeNi layers and AlCoCrFeNi layers; the number of layers in the composite layer is 500, and the thickness of each layer is 0.08 mm;

[0059] 2) The composite layer is placed in a muffle furnace, heat treated at 700° C. for 6 h, and then naturally cooled to room temperature to obtain a high-strength, high-toughness, high-entropy alloy composite material.

[0060] Figure 1 This is a SEM image of the high-strength, high-toughness, high-entropy alloy composite material prepared in Example 1 of the present invention. The bright part is AlCoCrFeNi, and the dark part is CoCrFeNi. Figure 1 It can be seen that the high-strength, high-toughness, high-entropy alloy composite material of the present invention has a layered structure.

[0061] Figure 2 This is a phase structure diagram of the high-strength, high-toughness, high-entropy alloy composite material prepared in Example 1 of the present invention. Figure 2 It can be seen that the distributed phase organization presents a layered distribution.

[0062] Figure 3This is a physical picture of the CoCrFeNi alloy and the high-strength, high-toughness, high-entropy alloy composite material of Example 1 of the present invention. Figure 3 The left picture is a physical picture of CoCrFeNi alloy. Figure 3 The right picture in the figure is a physical picture of the high strength, high toughness and high entropy alloy composite material of Example 1 of the present invention. Figure 3 It can be seen that the high-strength, high-toughness, high-entropy alloy composite material of the present invention has good formability.

[0063] The tensile properties of the high-strength, high-toughness, high-entropy alloy composite material prepared in Example 1 of the present invention were tested using an MTS Exceed E43 electronic universal testing machine (5N-10kN). The results are as follows: Figure 4 shown. Figure 4 This is a tensile performance diagram of the high-strength, high-toughness, high-entropy alloy composite material prepared in Example 1 of the present invention.

[0064] Comparative Example 1

[0065] The difference from Example 1 is:

[0066] The AlCoCrFeNi powder was replaced with CoCrFeNi powder.

[0067] The remaining steps are the same as those in Example 1 to obtain a composite material.

[0068] The tensile properties of the composite material prepared in Comparative Example 1 of the present invention were tested using an MTS Exceed E43 electronic universal testing machine (5N-10kN). The results are as follows: Figure 5 shown. Figure 5 This is a graph showing the tensile properties of the composite material prepared in Comparative Example 1 of the present invention.

[0069] Comparison of Example 1 and Comparative Example 1 shows that the yield strength, tensile strength and elongation of the composite material prepared by the present invention are significantly better than those of the comparative example.

[0070] The above embodiments are intended only to facilitate understanding of the methods and core concepts of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is intended to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-strength, high-toughness, high-entropy alloy composite material, comprising the following steps: A) In a protective gas atmosphere, CoCrFeNi powder and Al x CoCrFeNi powders are alternately deposited by a directed energy deposition process to form a composite layer group; Wherein, x=0.2, 0.4, 0.6, 0.8 or 1.0; B) heat treating the composite layer group at 700° C. to 1100° C. to obtain a high-strength, high-toughness, high-entropy alloy composite material.

2. The preparation method according to claim 1, characterized in that The parameters of the directed energy deposition include: The laser power is 800-1800W, the scanning speed is 6-15mm / s, the laser beam spot diameter is 3mm, and the transfer speed is 0.5-6.0rpm.

3. The preparation method according to claim 1, characterized in that The particle size of the CoCrFeNi powder is 45 to 150 μm.

4. The preparation method according to claim 1, characterized in that The Al x The particle size of the CoCrFeNi powder is 45 to 150 μm.

5. The preparation method according to claim 1, characterized in that The protector is argon gas.

6. The preparation method according to claim 1, characterized in that The thickness of each layer in the composite layer group is 0.05-0.1 mm.

7. The preparation method according to claim 1, characterized in that The heat treatment time is 4 to 6 hours.

8. The preparation method according to claim 1, characterized in that After the heat treatment, the method further comprises cooling.

9. A high-strength, high-toughness, high-entropy alloy composite material prepared by the preparation method according to any one of claims 1 to 8.

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