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

Abstract

This invention relates to the field of high-entropy alloy materials, and more particularly to a high-strength, high-toughness, high-entropy alloy composite material and its preparation method. The preparation method of the high-strength, high-toughness, high-entropy alloy composite material includes the following steps: A) Under a protective gas atmosphere, CoCrFeNi powder and Al... x CoCrFeNi powder is alternately deposited using a directional energy deposition process to form a composite layer; wherein x = 0.2, 0.4, 0.6, 0.8, or 1.0; B) The composite layer is heat-treated at 700℃~1100℃ to obtain a high-strength, high-toughness, and high-entropy alloy composite material. The high-strength, high-toughness, and high-entropy alloy composite material of this invention effectively utilizes the high plasticity of CoCrFeNi and the high strength of AlxCoCrFeNi. Through the control of the layered structure, high-strength and high-toughness material properties are achieved, giving it broad application potential in aerospace, nuclear power, and deep-sea equipment.

Description

Technical Field

[0001] This invention relates to the field of high-entropy alloy materials, and more particularly to a high-strength, high-toughness, high-entropy alloy composite material and its preparation method. Background Technology

[0002] With the increasing demand for lightweight, high-strength, and high-toughness materials in aerospace, defense, and high-end manufacturing, traditional metallic materials can no longer meet the service requirements in certain extreme environments. In recent years, the emergence of high-entropy alloys (HEAs) has provided a completely new research perspective and design concept for the field of materials science. HEAs are composed of multiple metallic elements in equimolar or near-equimolar ratios. Their significant characteristics include the high-entropy effect, delayed diffusion effect, severe lattice distortion, and the "cocktail effect," which endow HEAs with 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, simultaneously satisfying the seemingly contradictory properties of high strength and high toughness remains a technical challenge. 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, and high-entropy alloy composite material and its preparation method. The high-strength, high-toughness, and 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 widely used in the manufacture and repair of high-performance alloys due to its ability to construct complex geometries "point by point and layer by layer" in three-dimensional space. Compared with other additive manufacturing technologies such as Selective Laser Melting (SLM) and Electron Beam Melting (EBM), DED technology can directly deposit materials on the surface of existing parts, thereby enabling in-situ repair and multi-material printing.

[0006] However, additive manufacturing often faces problems such as high thermal stress, coarse grains, porosity, and crack defects. In DED technology, parameters such as laser power, scanning speed, powder flow rate, and cooling rate directly affect the forming quality and microstructure of the deposited layer. Furthermore, the multi-principal component design of high-entropy alloys makes their solidification behavior more complex.

[0007] Currently, most research on DED additive manufacturing of high-entropy alloys focuses on optimizing process parameters and controlling microstructure and properties of single high-entropy alloys. However, selecting which two high-entropy alloys can work well together, and how to achieve layer-to-layer metallurgical bonding, compositional transition control, and thermal stress relief between these two high-entropy alloys, remain core technical challenges in multi-material additive manufacturing.

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

[0009] A) Under a protective atmosphere, CoCrFeNi powder and Al x CoCrFeNi powder was deposited alternately using a directional energy deposition process to form a composite layer.

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

[0011] B) The composite layer group is heat-treated at 700℃~1100℃ to obtain a high-strength, high-toughness, and high-entropy alloy composite material.

[0012] Preferably, the parameters for the directional energy deposition include:

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

[0014] Preferably, the CoCrFeNi powder has a particle size of 45–150 μm.

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

[0016] Preferably, the protector is argon.

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

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

[0019] Preferably, the heat treatment further includes cooling.

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

[0021] This invention provides a method for preparing a high-strength, high-toughness, and high-entropy alloy composite material, comprising the following steps: A) Under a protective atmosphere, CoCrFeNi powder and AlxCoCrFeNi powder are alternately deposited using a directional energy deposition process to form a composite layer; wherein x = 0.2, 0.4, 0.6, 0.8, or 1.0; B) The composite layer is heat-treated at 700℃ to 1100℃ to obtain the high-strength, high-toughness, and high-entropy alloy composite material. The high-strength, high-toughness, and high-entropy alloy composite material of this invention effectively utilizes the high plasticity of CoCrFeNi and the high strength of AlxCoCrFeNi. Through the control of the layered structure, high-strength and high-toughness material properties are achieved, giving it broad application potential in aerospace, nuclear power, and deep-sea equipment. Attached Figure Description

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

[0023] Figure 2 The phase structure diagram of the high-strength, high-toughness, and high-entropy alloy composite material prepared in Example 1 of this invention is shown.

[0024] Figure 3 The image shows a physical copy of the CoCrFeNi alloy and the high-strength, high-toughness, high-entropy alloy composite material of Example 1 of this invention.

[0025] Figure 4 The tensile properties of the high-strength, high-toughness, and high-entropy alloy composite material prepared in Example 1 of this invention are shown in the diagram.

[0026] Figure 5 This is a diagram showing the tensile properties of the composite material prepared in Comparative Example 1 of this invention. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

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

[0029] A) Under a protective atmosphere, CoCrFeNi powder and Al x CoCrFeNi powder was deposited alternately using a directional energy deposition process to form a composite layer.

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

[0031] B) The composite layer group is heat-treated at 700℃~1100℃ to obtain a high-strength, high-toughness, and high-entropy alloy composite material.

[0032] Regarding step A):

[0033] Under a protective atmosphere, CoCrFeNi powder and Al x CoCrFeNi powder was deposited alternately using a directional energy deposition process to form a composite layer.

[0034] Where 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] This invention relates to the CoCrFeNi powder and Al x There are no special restrictions on the source of CoCrFeNi powder; it can be commercially available or homemade. For example, the CoCrFeNi powder can be obtained from CoCrFeNi alloy material through gas atomization or mechanical pulverization in an argon atmosphere. The particle size of the CoCrFeNi powder is 45–150 μm to ensure stable powder feeding and uniform deposition during DED additive manufacturing. The Al... x CoCrFeNi powder can be made from Al x CoCrFeNi alloy materials are prepared in an argon atmosphere by gas atomization or mechanical pulverization. The Al... x The CoCrFeNi powder has a particle size of 45–150 μm to ensure stable powder feeding and uniform deposition during DED additive manufacturing.

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

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

[0039] The directional energy deposition is performed using directional energy deposition laser additive manufacturing equipment from Han's Laser Technology Industry Co., Ltd., equipped with a 500W to 3000W laser, such as a 3000W laser.

[0040] The directional energy deposition process in this invention can avoid common additive manufacturing defects such as porosity, lack of fusion and cracks, resulting in materials with dense microstructure and excellent interfacial bonding strength.

[0041] After alternating deposition using a directional energy deposition process, a CoCrFeNi layer and an Al layer were obtained. xA layered structure consisting of alternating CoCrFeNi layers. In 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 was heat-treated at 700℃~1100℃ to obtain a high-strength, high-toughness, and 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. The heat treatment process is completed in a box-type resistance furnace (within a muffle furnace).

[0045] The heat treatment process also includes cooling, specifically natural 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 in the Al... x Nanoscale Al-rich reinforcing 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. This results in a yield strength and hardness increase of more than 20%, and a significant reduction in anisotropy, thereby improving the long-term service stability and high-temperature environmental adaptability of the material.

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

[0048] The high-strength, high-toughness, and high-entropy alloy composite material in this invention effectively leverages the high plasticity of CoCrFeNi and the high properties of Al. x The high strength of CoCrFeNi is achieved through the control of its layered structure, resulting in high strength and high toughness. It also exhibits excellent crack propagation resistance 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 propagation resistance and fatigue resistance under tensile, compressive, and impact loads, with a well-matched yield strength and elongation. This structure effectively suppresses crack initiation and propagation under high stress and high impact loads, possessing high strength and high toughness advantages, making it a promising candidate for applications in aerospace, nuclear power, and deep-sea equipment.

[0050] To further illustrate the present invention, the following detailed description of a high-strength, high-toughness, high-entropy alloy composite material and its preparation method provided by the present invention is provided in conjunction with embodiments, but it should not be construed as limiting the scope of protection of the present invention.

[0051] In this embodiment, directional energy deposition employs a laser cladding system, model HLC-30 from Han's Laser. The system mainly consists of an Etelux Lab unidirectional glove box, a Fanuc R2000i six-axis industrial robot, a Han's 3000W fiber laser (laser wavelength approximately 1076nm), and a four-channel coaxial powder feeder. During cladding, the glove box maintains a pressure of 1.0–3.0 mbar throughout the process and continuously supplies 99.999% pure argon gas with a water and oxygen content below 10 ppm.

[0052] The CoCrFeNi powder used in the examples had a particle size of 45–150 μm, and Al x The CoCrFeNi powder has a particle size of 45–150 μm and all of it comes from Chengdu Kewan Company.

[0053] Example 1

[0054] Preparation of high-strength, high-toughness, and high-entropy alloy composite materials:

[0055] 1) Under an argon atmosphere, CoCrFeNi powder and AlCoCrFeNi powder are alternately deposited using a directional energy deposition process to form a composite layer.

[0056] The parameters for the directional energy deposition are:

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

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

[0059] 2) The composite layer was heat-treated at 700°C for 6 hours in a muffle furnace and then naturally cooled to room temperature to obtain a high-strength, high-toughness, and 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 this invention. The bright areas represent AlCoCrFeNi, and the dark areas represent CoCrFeNi. From... Figure 1 It can be seen that the high-strength, high-toughness, and 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. From... Figure 2 As can be seen, the distribution phases exhibit a layered distribution.

[0062] Figure 3The images show physical specimens of the CoCrFeNi alloy and the high-strength, high-toughness, high-entropy alloy composite material of Example 1 of this invention. Figure 3 The left image in the image is a physical photograph of the CoCrFeNi alloy. Figure 3 The right figure in the image is a physical photograph of the high-strength, high-toughness, high-entropy alloy composite material of Embodiment 1 of the present invention. From... Figure 3 It can be seen that the high-strength, high-toughness, and high-entropy alloy composite material of the present invention has good formability.

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

[0064] Comparative Example 1

[0065] The difference from Example 1 is as follows:

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

[0067] The remaining steps are the same as in Example 1, and the composite material is obtained.

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

[0069] As can be seen from the comparison between Example 1 and Comparative Example 1, 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 descriptions of the above embodiments are merely illustrative of the methods and core ideas 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 invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope 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) Under a protective atmosphere, CoCrFeNi powder and AlCoCrFeNi powder are alternately deposited by directional energy deposition process to form a composite layer group; the composite layer group is a layered structure of alternating CoCrFeNi layer and AlCoCrFeNi layer; The parameters for the directional energy deposition include: The laser power is 800~1800 W, the scanning speed is 6~15 mm / s, the laser beam diameter is 3 mm, and the transfer speed is 0.5~6.0 rpm; The thickness of each layer in the composite layer group is 0.05~0.1 mm; B) After heat-treating the composite layer at 700℃~1100℃ for 4~6 h, it is naturally cooled to room temperature to obtain a high-strength, high-toughness, high-entropy alloy composite material. After heat treatment, the columnar grains in the CoCrFeNi and AlCoCrFeNi layers gradually transform into equiaxed grains, and a nanoscale Al-rich strengthening phase precipitates in the AlCoCrFeNi layer. The precipitated phase hinders dislocation slip and crack propagation.

2. The preparation method according to claim 1, characterized in that, The CoCrFeNi powder has a particle size of 45~150 μm.

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

4. The preparation method according to claim 1, characterized in that, The protective gas is argon.

5. The high-strength, high-toughness, high-entropy alloy composite material prepared by the preparation method according to any one of claims 1 to 4.

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