Preparation method and application of a super-elastic metal metamaterial

Abstract

This invention discloses a method for preparing and applying a hyperelastic metallic metamaterial. The preparation method includes: selecting a bending metamaterial based on the Maxwell equation, which is: m = b - 3j + 6, where b and j are the number of rods and nodes, respectively, and the material is a bending metamaterial when m is less than 0; selecting a matrix material and preparing the hyperelastic metallic metamaterial using laser powder bed melting 3D printing. In particular, the bending metamaterial can be selected from body-centered cubic metamaterials, face-centered cubic metamaterials, or orthogonal dodecahedral metamaterials. The elastic strain of the hyperelastic metallic metamaterial in this invention is about 10 times that of existing commercial metallic materials, an improvement of nearly an order of magnitude, and has important application value in the field of engineering materials such as artificial bone energy absorbers in medical devices.

Description

Technical Field

[0001] This invention belongs to the field of metallic metamaterial design and preparation, specifically relating to a method for preparing and applying a hyperelastic metallic metamaterial. Background Technology

[0002] High-performance hyperelastic metallic materials possess extremely high strength, ultra-large elastic strain limits, and temperature-insensitive elastic modulus (Elinvar effect). They have become indispensable strategic metallic materials for the development of emerging industries, with applications ranging from actuators and medical devices to high-precision instruments. However, due to the easy slippage of dislocations, the elastic strain limit of bulk crystalline metals is typically less than 1%. Shape memory alloys, including colloidal metals and strain glass alloys, can achieve elastic strain limits as high as several percent, although this is a pseudoelastic result accompanied by significant energy dissipation. Currently, many metallic components are used in applications requiring elastic deformation, particularly in mechanical parts such as artificial bones, dental materials, or springs, which demand low Young's modulus and high elastic strain.

[0003] Elastic strain is caused by a reversible change in the interatomic distance in a crystal lattice. Although theoretical predictions suggest elastic strain exceeding 10%, due to strength limitations, the elastic strain of most metallic materials in reality generally does not exceed 5%, and is mostly below 1% (e.g., Figure 1 As shown in the figure, the lower the Young's modulus of a material, the lower its strength. Achieving both low Young's modulus and high strength is a major challenge. High elastic strain metallic materials have significant application value in the fields of medical devices and engineering materials. Hyperelasticity refers to the strain that a metallic material can recover during compression (except for the pseudoelastic strain of Ni-Ti alloys). It is very close to the concepts of strong Möbi (the ratio of strength to modulus) or elastic allowable strain (EAS). Hyperelastic strain is an important indicator pursued by metallic medical devices. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the main objective of the present invention is to provide a method for preparing a superelastic metallic metamaterial, wherein the elastic strain of the superelastic metallic metamaterial is about 10 times that of existing commercial metallic materials.

[0005] Another object of the present invention is to provide a superelastic metallic metamaterial obtained by the preparation method of the superelastic metallic metamaterial.

[0006] Another object of the present invention is to provide the application of the aforementioned hyperelastic metallic metamaterial in medical devices or engineering materials.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] This invention provides a method for preparing a superelastic metallic metamaterial, comprising the following steps:

[0009] Step 1: Select a bending metamaterial based on the Maxwell equation. The Maxwell equation is: m = b - 3j + 6, where b and j are the number of rods and nodes, respectively. It also satisfies that when m is less than 0, it is a bending metamaterial.

[0010] Step 2: Select a matrix material and use laser powder bed melting 3D printing to prepare a superelastic metallic metamaterial.

[0011] Preferably, the curved metamaterial is selected from one of body-centered cubic metamaterials, face-centered cubic metamaterials, and orthogonal dodecahedral metamaterials.

[0012] Preferably, the bending metamaterial is a body-centered cubic metamaterial with a unit cell size of 5.77 mm, a rod length of 5 mm, a rod diameter of 0.35 mm, and a relative density of 2%.

[0013] Preferably, the matrix material is TC4 alloy. Since the elastic strain of metallic metamaterials is related to their structure, relative density and matrix material, the elastic strain of TC4 alloy is 0.9%, which is relatively high in the field of metallic materials.

[0014] Preferably, the process parameters for laser powder bed melting 3D printing include: laser power of 95W, layer thickness of 20μm, scanning speed of 1200mm / s, hatch spacing of 80μm, threshold of hatch vector filter of 0.1 micrometer, and the Ti-6Al-4V plate is preheated to 100℃ and then rotated 90° between each layer in a herringbone incubation method (67°).

[0015] In the aforementioned method for preparing hyperelastic metallic metamaterials, on the one hand, the smaller the material density, the greater the elastic strain. By optimizing the topological parameters such as rod length, unit cell size, and rod diameter of the bending metamaterial, its relative density is minimized, while a matrix material with large elastic strain is selected. On the other hand, the greater the loading rate, the greater the elastic strain. The loading rate of the laser powder bed melting 3D printing process is controlled.

[0016] The present invention also provides a superelastic metallic metamaterial, which is obtained by the preparation method of the superelastic metallic metamaterial.

[0017] The present invention also provides the application of the aforementioned hyperelastic metallic metamaterial as an engineering material in the preparation of medical devices.

[0018] Preferably, the superelastic metallic metamaterial is used as an energy-absorbing material for artificial bone.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: the elastic strain of the superelastic metallic metamaterial designed by the present invention is about 10 times that of existing commercial metallic materials, which is nearly an order of magnitude higher, and has important application value in the field of engineering materials such as artificial bone energy absorbers in medical devices. Attached Figure Description

[0020] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0021] Figure 1 This is a schematic diagram of the elastic strain distribution of metallic materials in the prior art.

[0022] Figure 2 This is a schematic diagram of the body-centered cubic metamaterial topology in the embodiment.

[0023] Figure 3 The image shows a body-centered cubic metamaterial prepared by laser powder bed melting 3D printing technology in this embodiment and its characterization diagram.

[0024] Figure 4 The static compression curve of the body-centered cubic metamaterial in this embodiment is shown.

[0025] Figure 5 The loading and unloading curves of the body-centered cubic metamaterial in this embodiment are shown. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The following embodiments employ a method for preparing hyperelastic metallic metamaterials, including the following steps:

[0028] Step 1: Select a bending metamaterial based on the Maxwell equation. The Maxwell equation is: m = b - 3j + 6, where b and j are the number of rods and nodes, respectively. It also satisfies that when m is less than 0, it is a bending metamaterial.

[0029] Step 2: Select a matrix material and use laser powder bed melting 3D printing to prepare a superelastic metallic metamaterial.

[0030] The technical solution of the present invention will be described below through specific embodiments.

[0031] Example 1

[0032] In this embodiment, the body-centered cubic metamaterial is prepared using the following steps:

[0033] Step 1: Select a bending metamaterial based on Maxwell's equations. Maxwell's equations are: m = b - 3j + 6, where b and j are the number of rods and nodes, respectively. A bending metamaterial is defined as m < 0. The bending metamaterial is a body-centered cubic metamaterial. Figure 1 Its body-centered cubic crystal structure has a unit cell size of 5.77 mm, a rod length of 5 mm, a rod diameter of 0.35 mm, and a relative density of 2%. Figure 2 ).

[0034] Step 2: Select TC4 alloy as the matrix material and use laser powder bed melting 3D printing to prepare a superelastic metallic metamaterial. Figure 3 The process parameters for laser powder bed melting 3D printing are as follows: laser power is 95W, layer thickness is 20μm, scanning speed is 1200mm / s, hatch spacing is 80μm, threshold of hatch vector filter is 0.1 micrometer, Ti-6Al-4V plate is selected and preheated to 100℃, and then rotated 90° between each layer in a herringbone incubation method (67°).

[0035] The hyperelastic metallic metamaterial prepared in Example 1 was subjected to static compression and loading / unloading experiments. The static compression curve is shown below. Figure 4 As shown, its yield strength and Young's modulus are 0.33 MPa and 3.35 MPa, respectively. The compressive strain rate is 1 mm / min. As the loading rate increases, the yield strength increases, but the modulus remains essentially unchanged; therefore, its elastic strain also increases. Due to its relatively low stress, the maximum load selected for the load is 2.5 kN. The loading and unloading curves are shown below. Figure 5 As shown, the recoverable strain clearly demonstrates that the elastic strain of the hyperelastic metallic metamaterial reaches 9.4%. The test data of Example 1 show that the elastic strain of the hyperelastic metallic metamaterial designed in this invention is about 10 times that of existing commercial metallic materials, an improvement of nearly an order of magnitude, and has important application value in the field of engineering materials such as artificial bone energy absorbers in medical devices.

[0036] The present invention has been described in detail above through embodiments, but the content is only a preferred example of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A method of making an ultralastic metal metamaterial, characterized by, It comprises the following steps: Step 1: selecting a bending metamaterial according to Maxwell equation, Maxwell equation is: m = b - 3j + 6, wherein b and j are the number of rods and nodes respectively, and the bending metamaterial is satisfied when m is less than 0; Step 2: selecting a base material, and preparing the super-elastic metal metamaterial by laser powder bed fusion 3D printing; The bending metamaterial is a body-centered cubic metamaterial, the unit cell size of the body-centered cubic crystal structure is 5.77 mm, the rod length is 5 mm, the rod diameter is 0.35 mm, and the relative density is 2%; The base material is TC4 alloy.

2. The method of claim 1, wherein the superelastic metal metamaterial is prepared by the steps of: The process parameters of the laser powder bed fusion 3D printing include: laser power is 95 W, layer thickness is 20 μm, scanning speed is 1200 mm / s, hatch spacing is 80 μm, threshold value of hatch vector filter is 0.1 microns, Ti-6Al-4V plate is preheated to 100 DEG C, and then a herringbone incubation method is used to rotate 90 DEG between layers to obtain. ​ 3. An ultralastic metal metamaterial, characterized by, The super-elastic metal metamaterial is obtained by the preparation method of claim 1 or 2.

4. The application of the super-elastic metal metamaterial of claim 3 as an engineering material in the preparation of medical devices.

5. Use according to claim 4, characterised in that, The super-elastic metal metamaterial is used as an artificial bone energy-absorbing material.

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