CN111304557A

CN111304557A - Metal glass metamaterial with fold structure

Info

Publication number: CN111304557A
Application number: CN202010202195.3A
Authority: CN
Inventors: 沙振东; 滕云; 张家宬; 林伟辉
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2020-03-20
Filing date: 2020-03-20
Publication date: 2020-06-19
Anticipated expiration: 2040-03-20
Also published as: CN111304557B

Abstract

The invention discloses a metal glass metamaterial with a folded structure, which has an obvious toughening effect, can be suitable for any metal glass system and can be prepared into a large-scale structural member. The invention can effectively realize the aims of energy absorption, energy storage, vibration reduction and the like, and can be applied to structural members of vibration-proof buildings and automobile vibration-proof devices. When the automobile runs on a bumpy road, the vibration of the automobile is greatly weakened by utilizing the excellent vibration damping capacity of the invention, and the automobile also runs more stably. When an earthquake occurs, the energy absorption device has excellent energy absorption characteristics, can absorb the energy of earthquake waves to the maximum extent, and reduces the damage to buildings in the earthquake. The invention has simple structure, can greatly improve the room temperature plasticity of the metal glass, has nearly twice toughness as the original toughness, and retains the excellent performances of the metal glass such as high elasticity, high strength, high wear resistance and the like.

Description

Metal glass metamaterial with fold structure

Technical Field

The invention belongs to the field of metamaterial technology and structural optimization design, and particularly relates to a metal glass metamaterial with a fold structure.

Background

Metallic glasses, also known as amorphous alloys, are amorphous solids obtained by rapidly cooling a metal melt in a molten state. The metal glass has a microstructure with medium-short range order and long range disorder, so that defects such as dislocation, grain boundary and the like can not occur. Compared to traditional crystalline metallic materials, metallic glass materials exhibit a number of unique physical, chemical and mechanical properties, such as: high elastic limit, high strength, wear and corrosion resistance, etc. In addition, the metal glass has good thermoplastic forming capability, and is easy to process and form. Although metallic glass has many excellent properties, the fracture mode of metallic glass is represented by brittle fracture in which shear band rapidly expands due to the absence of plastic deformation mechanisms such as slip planes, dislocations, and the like, the room temperature plastic deformation capability is extremely poor, and generally the tensile plastic strain is nearly 0.

At present, aiming at the defect of high brittleness of the metal glass, a plurality of toughening methods are also proposed, including a porous structure, a composite material, a size effect and the like, but the methods have a plurality of limitations. Although the deformation capability of the metal glass can be improved, the Young modulus and the strength of the metal glass can be seriously reduced, and the porous structure has a complex shape and is relatively difficult to prepare. The composite material can only be applied to a limited metal glass system, and a second phase needs to be introduced, so that the requirement on the preparation process is high. The size effect can realize large deformation and high strength, but is only limited under the nanometer scale and cannot be applied to large-scale structural parts.

Disclosure of Invention

The invention aims to overcome the defects and provide the metal glass metamaterial with the fold structure, and the fold structure is utilized to introduce a stress gradient into the metal glass material, so that the expansion of a metal glass shear band is inhibited, the room temperature plasticity of the metal glass is improved, and the mechanical property of the metal glass is improved.

In order to achieve the purpose, the invention comprises a plurality of periodically arranged fold structures which have the same size and consistent shape and are connected; each fold structure comprises a first ligament and a second ligament, and the first ligament and the second ligament are in arc shapes with the same size and shape; the first ligament and the second ligament both comprise an inner side surface and an outer side surface, and the inner side surface and the outer side surface are arcs with the same circle center, different radiuses and the same circle center angle.

The material of the fold structure is metal glass.

The characteristic dimension of the fold structure is in the nanometer order to the centimeter order.

The central angle of the circular arc is theta₀Angle of center of circle theta₀For regulating strength, central angle theta₀The smaller the overall strength, the weaker the deformability.

The radius of the inner side surface of the first ligament and the second ligament is a, the radius of the outer side surface is b, and the inner side radius a and the outer side radius b are used for controlling the fracture mode and the deformability;

when in use

When the value is larger than the corresponding critical value, the structure is subjected to shear brittle fracture;

when in use

When the value is less than the corresponding critical value, the structure is subjected to plastic fracture, the deformability is strengthened, and the toughness is increased.

And (3) carrying out integrated preparation by adopting a thermoplastic molding technology or a 3D printing technology.

Compared with the prior art, the metallic glass metamaterial with the fold structure provided by the invention has an obvious toughening effect, can be suitable for any metallic glass system, and can be prepared into a large-scale structural member. The invention can effectively realize the aims of energy absorption, energy storage, vibration reduction and the like, and can be applied to structural members of vibration-proof buildings and automobile vibration-proof devices. When the automobile runs on a bumpy road, the vibration of the automobile is greatly weakened by utilizing the excellent vibration damping capacity of the invention, and the automobile also runs more stably. When an earthquake occurs, the energy absorption device has excellent energy absorption characteristics, can absorb the energy of earthquake waves to the maximum extent, and reduces the damage to buildings in the earthquake. The invention can greatly improve the room temperature plasticity of the metal glass although the structure is simple, simultaneously, the toughness is nearly twice of the original toughness, and the invention keeps the advantages of high elasticity, high strength, high wear resistance and the like of the metal glassThe properties are different. According to the invention, through a simple structural design, a stress gradient from pressing to pulling is introduced, the propagation of a shear band is inhibited, and the toughening of the metal glass is realized. And the structural characteristic parameters (inside radius a, outside radius b, central angle theta) of the corrugated structure₀) The adjustable damping device is easy to adjust and control, and can effectively control the overall mechanical property and deformation and fracture mechanism of the structure to adapt to different workplaces, so that the adjustable damping device can meet unique requirements of special fields, such as requirements of damping, energy absorption, energy storage and the like.

Further, the structure scale of the invention can be from nanometer scale to centimeter scale. The fold structure has simple shape, is easy to regulate and control, is easy to prepare due to the good thermoplastic forming capability of the metal glass, can reach the surface precision of nanometer level, and can realize the multi-scale precise preparation from the nanometer range to the macroscopic field.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a stress-strain comparison graph of the present invention and a metallic glass plate; wherein (a) is metallic glass; (b) the invention is the following;

wherein, 1, the first ligament, 2, the second ligament.

Detailed Description

The invention will be further explained with reference to the drawings.

Referring to fig. 1, the invention comprises a plurality of corrugated structures which have the same size and shape and are periodically arranged and connected; each fold structure comprises a first ligament 1 and a second ligament 2, and the first ligament 1 and the second ligament 2 are in arc shapes with the same size and shape; the first ligament 1 and the second ligament 2 both comprise an inner surface and an outer surface, the inner surface and the outer surface are in the shape of the same circle center, different radiuses and the central angle is theta₀The radius of the inner side surface is a and the radius of the outer side surface is b. The material of the fold structure is metal glass.

The invention combines the excellent mechanical property of the metal glass with the characteristic of the fold structure, introduces the stress gradient from pressing to pulling through the structural design, inhibits the propagation of the shear band,thereby greatly improving the room temperature plasticity of the metal glass and improving the capability of the whole structure for bearing large deformation and large load. Furthermore, the fold structure can be optimally designed according to the requirement, as shown in figure 1, by adjusting the central angle theta₀The inner radius a and the outer radius b change the shape of the folds, and the mechanical properties such as strength, Young modulus, deformability, toughness and fracture mechanism are regulated and controlled, so that the requirements in various aspects such as energy absorption, energy storage and vibration reduction are met. Wherein the central angle theta₀The overall strength, central angle theta, of the structure being controlled₀The smaller the overall strength, the higher the deformability becomes weaker; the inside radius a and outside radius b control the fracture mode and deformability when

When the value is larger than the corresponding critical value, the structure is subjected to shear brittle fracture; when in use

When the fracture mode is less than the corresponding critical value, the fracture mode is transformed, and the deformability and the toughness are greatly enhanced. The fracture mode of the structure is now transformed from brittle fracture to plastic fracture due to the introduction of a stress gradient from compressive to tensile. The bud of shear band is at first sprouting in stress concentration area, owing to there is by pressing to the stress gradient of drawing, can't continue outside extension after the shear band sprout maturity, can lead to the appearance of shear band intercrossing phenomenon, further hinders the extension of restraining the shear band for the plastic fracture takes place for the material. This results in a substantial increase in the deformability of the structure, with a concomitant increase in toughness of up to approximately twice that of the original, as shown in figure 2.

Due to the high elasticity and high strength of the metallic glass, the deformation limit and the load bearing limit of the metallic glass structural member are very considerable. And the ultrahigh elastic limit of the metal glass is benefited, and after the metal glass is unloaded, as long as the deformation degree does not reach the elastic limit, the structural member can be quickly restored to the initial form, so that the structural member can bear multiple loading, and the metal glass can be conveniently used repeatedly. In addition, the metal glass surface atoms are arranged compactly, so that the nano-scale surface precision can be realized, and the required folded structure component can be completely and accurately processed.

Because the metal glass has good thermoplasticity, the metal glass with the fold structure can be prepared by adopting a thermoplastic forming technology, and the structural member prepared by the technology has high dimensional precision and does not need secondary processing. In addition, with the gradual maturity of the metal glass additive manufacturing technology, a 3D printing technology can be adopted for design and preparation, and the application range of the metal glass material with the fold structure provided by the invention is further expanded. Firstly, controlling model design and program writing through a computer; then, pre-paving metal glass powder with a certain thickness on a substrate positioned on the lifting platform; then, the laser beam is selectively scanned according to a pre-programmed program; after the scanning is finished, the lifting platform is lowered for a certain distance to ensure the focusing of the laser beam, and the scanning is restarted; repeating the above processes, and finally accumulating layer by layer to prepare the metallic glass with the required geometric shape.

The invention uses high-strength, high-wear-resistance and high-corrosion-resistance metal glass as a preparation material, so the process of corrosion, wear and damage of the corresponding structural part is very slow.

The invention benefits from the high elastic limit of the metal glass, and after unloading, as long as the elastic limit is not reached, the corresponding structural member can be quickly restored to the initial form, so that the structural member can bear multiple loading, and is convenient to be repeatedly used for multiple times.

Claims

1. The metal glass metamaterial with the corrugated structure is characterized by comprising a plurality of corrugated structures which are identical in size and shape and are arranged periodically, wherein the corrugated structures are connected; each fold structure comprises a first ligament (1) and a second ligament (2), and the first ligament (1) and the second ligament (2) are in circular arc shapes with the same size and shape; the first ligament (1) and the second ligament (2) both comprise an inner surface and an outer surface, and the inner surface and the outer surface are arcs with the same circle center, different radiuses and the same circle center angle.

2. The metallic glass metamaterial with a corrugated structure as claimed in claim 1, wherein the material of the corrugated structure is metallic glass.

3. The metallic glass metamaterial with a corrugated structure as claimed in claim 1, wherein the corrugated structure has a characteristic dimension of the order of nanometers to the order of centimeters.

4. The metallic glass metamaterial with a corrugated structure as claimed in claim 1, wherein the central angle of the circular arc is θ₀Angle of center of circle theta₀For regulating strength, central angle theta₀The smaller the overall strength, the weaker the deformability.

5. The metallic glass metamaterial with a corrugated structure as in claim 1, wherein the radius of the inner side surface of the first ligament (1) and the second ligament (2) is a, the radius of the outer side surface is b, and the inner side radius a and the outer side radius b are used for controlling the fracture mode and the deformability;

when in use

when in use

6. The metallic glass metamaterial with a corrugated structure as claimed in claim 1, wherein the metallic glass metamaterial is integrally prepared by using a thermoplastic molding technology or a 3D printing technology.