Amorphous alloy deep supercooling in-situ online neutron scattering measurement method

Abstract

The invention provides an amorphous alloy deep supercooling in-situ online neutron scattering measurement method. The method comprises the following steps: adding a heterogeneous material for triggering nucleation of a sample into the sample in a suspended and deep supercooling state; performing neutron scattering measurement on the sample in the process; according to the method, the molten metal material can trigger nucleation at any deep supercooling degree, so that the amorphous alloy with different supercooling degrees is obtained, the microstructure and the dynamic behavior of the amorphous alloy in different deep supercooling states are accurately measured, the rapid solidification mechanism of the amorphous alloy is explored, and the method has the advantages of being simple in structure, convenient to operate and the like. In addition, in the process from nucleation triggering to measurement, the sample does not need to be moved, the influence on the sample in the transferring process can be eliminated, and in-situ online measurement of the amorphous alloy is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of on-line neutron scattering measurement of amorphous alloys, and in particular to an in-situ on-line neutron scattering measurement method for deep undercooling of an amorphous alloy. Background Art

[0002] Amorphous alloys exhibit excellent physical and chemical properties due to their unique short-range order and long-range disorder structure, and are widely used in magnetic materials, biomedical materials and other fields.

[0003] During the experiment, containers are often used to transfer molten samples. In the case of containers, it is difficult to obtain equilibrium materials with spontaneous nucleation due to wall crystallization and heterogeneous nuclei rather than spontaneous nucleation. It is also difficult to obtain amorphous alloys in a deep supercooled state or at any supercooling degree. Therefore, the preparation and property research of amorphous alloys are usually limited by their stability in the supercooled state and the limitations of measurement technology. In addition, the traditional measurement method of amorphous alloys requires multiple sample transfers in the middle, which will interrupt the experiment and make it difficult to achieve in-situ online measurement of amorphous alloys. Moreover, the samples will be affected by various environmental factors such as the transfer container during the transfer process, which will affect the experimental results and research, which limits the in-depth understanding of their microstructure and dynamic behavior. Summary of the invention

[0004] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide an in-situ online neutron scattering measurement method for deep supercooling of amorphous alloys and a device for triggering nucleation, so as to solve the technical problem of online accurate measurement of the microstructure and dynamic behavior of amorphous alloys under different deep supercooling states.

[0005] To achieve the above objectives, the present invention provides an in-situ online neutron scattering measurement method for deep undercooling of an amorphous alloy, comprising: adding a heterogeneous substance for triggering sample nucleation into a suspended and deeply undercooled sample; and performing neutron scattering measurement on the sample during this process.

[0006] The present invention also provides a device for triggering nucleation, including a trigger mechanism and a guide tube. The trigger mechanism is used in the above-mentioned method to provide power for adding heterogeneous matter to the sample for triggering nucleation of the sample; the guide tube is used to guide the heterogeneous matter to be ejected in a predetermined direction. After the trigger mechanism hits the heterogeneous matter, the heterogeneous matter is ejected from the guide tube and injected into the sample.

[0007] The beneficial effects of the present invention are as follows: the method can trigger nucleation of molten metal materials at any deep supercooling, thereby obtaining amorphous alloys with different degrees of supercooling, and then accurately measure the microstructure and dynamic behavior of the amorphous alloys under different deep supercooling states, help explore the rapid solidification mechanism of amorphous alloys, and in the process from triggering nucleation to measurement, there is no need to move the sample, which can eliminate the influence of the sample during the transfer process and realize in-situ online measurement of amorphous alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A schematic diagram of the structure in which the sample is suspended and heated in the sample chamber;

[0009] Figure 2 A schematic diagram of the structure of a device for triggering nucleation;

[0010] Figure 3 A partial cross-sectional view of a part of a device for triggering nucleation is shown;

[0011] Figure 4 A schematic diagram of the structure of the device for triggering nucleation, the sample and related components;

[0012] Figure 5 A schematic diagram of the structure before the device for triggering nucleation, the upper electrode, the lower electrode and related components are placed in the sample chamber;

[0013] Figure 6 It is a schematic diagram of the explosion of the high voltage electrode and the sample chamber;

[0014] Figure 7 An exploded schematic diagram of the sample chamber and instrument mounting platform;

[0015] Figure 8 It is a schematic diagram of the structure after the sample chamber and the instrument mounting platform are installed;

[0016] Fig. 9 Schematic diagram of the process of installing the neutron scattering electrostatic levitator into the scattering cavity of the multi-physics spectrometer;

[0017] Description of reference numerals:

[0018] 1. Samples;

[0019] 2. Neutron scattering electrostatic levitator, 21. Ceramic flange, 22. Upper electrode, 23. Lower electrode, 24. Sample chamber, 25. High voltage electrode, 26. Instrument installation platform;

[0020] 3. Multi-physics spectrometer scattering cavity;

[0021] 41. trigger, 42. firing pin, 421. needle part, 422. stabilizing block, 43. storage tube, 44. guide tube, 451. fixing plate A, 452. fixing plate B, 453. base, 454. fixing frame. DETAILED DESCRIPTION

[0022] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0023] It should be noted that the diagram provided in the present embodiment only illustrates the basic concept of the present invention in a schematic manner, so the diagram only shows the units related to the present invention rather than drawing according to the number, shape and size of the units during actual implementation. The pattern, quantity and ratio of each unit during actual implementation can be a random change, and its unit layout pattern may also be more complicated. The structure, ratio, size, etc. illustrated by the drawings in the present specification are only used to match the content disclosed in the specification, so that people familiar with this technology can understand and read, and are not used to limit the limiting conditions that the present invention can implement, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope of the technical content disclosed by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of narration, and are not used to limit the scope of the present invention. The change or adjustment of its relative relationship should also be regarded as the scope of the present invention without substantially changing the technical content.

[0024] Because the molten amorphous material can be prevented from heterogeneous nucleation when it is not in contact with the container, the amorphous material can enter a deep supercooled state (the deep supercooled state means that it is still liquid at a temperature lower than its melting point) to obtain a metastable material. At the same time, it is also an ideal means to study the solidification mechanism of amorphous alloys. Therefore, keeping the amorphous material in a container-free suspension state is convenient for subsequent research.

[0025] Containerless suspension refers to an object floating in the air without any container or support. This phenomenon usually requires an external field or force to maintain the suspension state of the object. The main suspension technologies include magnetic suspension, acoustic suspension, air suspension, and electrostatic suspension. In this case, electrostatic suspension is used.

[0026] Because neutron scattering can be used to explore the mechanism of metastable phase formation during the solidification of metal materials, and currently in the field of high-energy X-rays and neutron scattering, the highest temperature provided by the sample environment is 1600°C, and combined with electrostatic levitation technology, the sample experimental temperature can be increased from 1600°C to 3000°C, so the neutron scattering electrostatic levitator provides a good experimental environment for studying the mechanism of metastable phase formation during the solidification of metal materials. This method realizes in-situ online neutron scattering measurement of deep supercooling of amorphous alloys in a neutron scattering electrostatic levitator.

[0027] The neutron scattering electrostatic levitator includes a sample chamber and an instrument chamber. After the sample chamber and the instrument chamber are sealed and connected, a closed sample vacuum chamber is formed. A plurality of windows connecting the inside and outside of the sample vacuum chamber are provided on the wall of the sample vacuum chamber, and a sample station for realizing sample electrostatic suspension is provided in the sample vacuum chamber. After the sample chamber and the instrument chamber are sealed and connected, the outer wall of the sample vacuum chamber and the inner wall of the multi-physics spectrometer scattering chamber form a scattering chamber. The top of the sample chamber and the bottom of the instrument chamber are connected by docking and sealing. After the connection, the instrument chamber and the sample chamber are connected to form a hollow cylindrical sample vacuum chamber. An optical device installation platform is installed on the upper part of the instrument chamber. Taking the optical device installation platform as a reference, the part below is the scattering chamber environment, and the part above is the atmospheric environment. For the specific structure of the neutron scattering electrostatic levitator, please refer to the patent number ZL202110718828.0.

[0028] Embodiment 1

[0029] This embodiment provides an in-situ online neutron scattering measurement method for deep supercooling of an amorphous alloy, comprising: adding a heterogeneous substance for triggering sample nucleation into a suspended and deeply supercooled sample; and performing neutron scattering measurement on the sample during this process.

[0030] This method can trigger nucleation of molten metal materials at any undercooling degree, thereby obtaining amorphous alloys with different undercooling degrees, and then accurately measure the microstructure and dynamic behavior of amorphous alloys under different deep undercooling states, helping to explore the rapid solidification mechanism of amorphous alloys. It should be noted that the sample described in this method is a metal material.

[0031] Since neutrons have the characteristics of strong penetration, no charge, and interaction with other particles, neutron scattering can be used to study the internal structure and dynamics of atomic nuclei, can be used to determine the precise three-dimensional structure of molecules, and can be used as a detection and analysis tool to study the static structure and dynamic processes of matter at the atomic and molecular scales. This method realizes the process before, during, and after the triggering of nucleation of the melt sample, all of which are completed in the neutron scattering electrostatic levitator, so there is no need to move the sample, and the in-situ analysis of amorphous alloys with different degrees of supercooling can be directly performed through neutron scattering, realizing in-situ online testing of amorphous alloys with different degrees of supercooling.

[0032] In this example, the steps for the sample to reach a suspended and deeply supercooled state are: first suspend the solid sample in a neutron scattering electrostatic levitator, then heat the sample, and stop heating after the sample becomes a melt; and allow the temperature of the molten sample to drop to the target temperature.

[0033] Before conducting the experiment, Fig. 9 As shown, the sample is first placed in a neutron scattering electrostatic levitator. Specifically, Figure 1 As shown, the sample is placed on the sample station for realizing the electrostatic suspension of the sample, the upper electrode and the lower electrode are installed in the sample cavity, and then the vacuum pump is connected to the cavity cover of the sample cavity to extract the air in the sample cavity until the sample cavity becomes a vacuum. In this example, the vacuum degree of the sample cavity where the sample is located reaches 10-5Pa. Then, the optical paths of each group of the neutron scattering electrostatic levitator are installed and adjusted, and the neutron scattering electrostatic levitator is installed as a whole in the scattering cavity of the multi-physics spectrometer. Then, the scattering cavity is vacuumed by the molecular pump unit on the scattering cavity of the multi-physics spectrometer. Then, the neutron scattering electrostatic levitator generates an electrostatic field, so that the sample is electrostatically suspended. There are multiple windows on the sample cavity. After the sample is suspended, the central axis of all the windows can pass through the suspended sample.

[0034] The basic principle of electrostatic levitation is that charged objects are acted upon by electric field forces in an electric field. As long as the electric field force is large enough, the object can overcome its own gravity and achieve levitation. In this example, the sample is acted upon by a total of four forces (F 总 ) are the Coulomb force F 库仑力 , the upward mirror force F 上 , the material's own gravity mg and the downward mirror force F 下 .

[0035] F 总 =F 库仑力 +F 上 -mg-F 下

[0036] When the resultant force F 总 When it is 0, the material is suspended.

[0037]

[0038] Where Q S is the charge of the material itself, U Z is the voltage difference between the upper and lower electrodes, d is the distance between the upper and lower electrodes, and z is the distance between the material and the lower electrode when it is suspended. ε0 is the dielectric constant, and the dielectric constant of vacuum ε0=8.854×10 -12 F·m -1 Therefore, by applying negative high voltage to the upper electrode and grounding the lower electrode, the sample can be electrically suspended.

[0039] The real-time suspension height position of different samples can be ensured by loading a voltage in the vertical direction to ensure that the sample is stably suspended between the upper electrode and the lower electrode, such as Figure 1 As shown in the figure, three two-dimensional position detectors (PSD) are used to locate the three-dimensional spatial position of the sample. After the positioning laser emitted by the positioning laser head passes through the sample, it passes through the filter and is projected on the circular spot on the PSD photosensitive surface of the position detector. A shadow appears. The center of gravity position of the shadow is converted into a voltage signal by the PSD. After the voltage signal is transmitted to the controller, the controller calculates the suspension control voltage through the PID algorithm, and amplifies the output control value by the high-voltage amplifier and loads it on the upper electrode.

[0040] Because electrostatic suspension has high stability, no external field disturbance, and the characteristics of suspension and heating are independent, the melt sample is little affected by external factors, so the solidification behavior of the supercooled suspended melt sample is mainly determined by the properties of the sample material itself. The degree of supercooling during nucleation of the supercooled melt sample is determined by the inherent properties of the material such as purity, solid-liquid interface energy and viscosity, as well as the cooling rate during the experiment. Since the electrostatic suspension experiment is carried out in an ultra-high vacuum environment (10-5Pa), the suspended melt sample only dissipates heat through thermal radiation. During the free cooling process, the cooling rate of the melt sample is determined, so the degree of supercooling of the supercooled melt sample in electrostatic suspension is generally not much different.

[0041] In order to control the undercooling of the melt sample during the experiment, active control of the undercooling must be achieved so that the melt sample can trigger nucleation at any undercooling degree.

[0042] In this example, a heating laser is used to heat the sample. After the sample becomes a melt, the heating laser is turned off to allow the melt sample to cool freely. When the melt sample reaches the target temperature, a neutron beam is emitted to the sample, and then a heterogeneous substance is added to the sample. The heterogeneous substance is used to trigger the heterogeneous nucleation of the sample. The heterogeneous substance is a molybdenum ball, a catalyst ball, or a ball of the same element as the sample. The diameter of the heterogeneous substance is less than or equal to 0.5 mm. Specifically, after the melt sample reaches the required temperature, that is, the desired supercooling, a neutron beam is emitted to the sample, and then a heterogeneous substance is added to the sample. The melt sample solidifies at the corresponding coldness, and an amorphous alloy at the corresponding coldness can be obtained. That is, by adding heterogeneous substances to a melt sample at any temperature below the melting point, active control of the supercooling is achieved, which provides convenience for studying the rapid solidification mechanism of the sample material. Repeating the above operation can obtain amorphous alloys at different coldness. The amorphous alloy obtained in this way belongs to a metastable material, that is, in this way, metastable materials with different supercooling degrees can be obtained.

[0043] It should be noted that the target temperature is any temperature lower than the melting point of the sample. In other words, the target temperature refers to the temperature at which nucleation of the melt sample is desired to be triggered, that is, any degree of supercooling to be maintained.

[0044] In this example, foreign matter is added to the sample by using a device for triggering nucleation to launch the foreign matter into the sample.

[0045] Embodiment 2

[0046] like Figure 2 and Figure 4 As shown, this embodiment provides a device for triggering nucleation, including a trigger mechanism and a guide tube 44. The trigger mechanism is used in the method described in any one of claims 1 to 6 to provide power for adding heterogeneous matter to the sample for triggering nucleation of the sample 1; the guide tube 44 is used to guide the heterogeneous matter to be ejected in a predetermined direction. After the trigger mechanism hits the heterogeneous matter, the heterogeneous matter is ejected from the guide tube and injected into the sample 1. The trigger mechanism provides power for the heterogeneous matter, and the guide tube 44 is used to guide the heterogeneous matter to be ejected in a predetermined direction. After the trigger mechanism hits the heterogeneous matter, the heterogeneous matter is ejected from the guide tube 44.

[0047] The trigger mechanism includes a striker 42 and a trigger 41. The trigger 41 is used to trigger the striker 42 to hit the foreign matter in the guide tube 44, so that the foreign matter is ejected along the guide tube 44. Specifically, the striker 42 includes a needle portion 421 and a stabilizing block 422. The side of the stabilizing block 422 facing the guide tube 44 is vertically connected to the needle portion 421, and the other side of the stabilizing block 422 is connected to the trigger 41, specifically by gluing; the end of the needle portion 421 away from the stabilizing block 422 can enter the guide tube 44 and collide with the foreign matter. In this example, the end of the needle portion 421 away from the stabilizing block 422 is located in the guide tube 44. The length of the needle portion 421 is less than or equal to the guide tube 44, so as to prevent the striker 42 from accidentally hitting the suspended sample 1.

[0048] In this example, the trigger 41 is a push-pull electromagnet, which is mainly composed of a coil and an iron core. When the coil of the push-pull electromagnet is energized, the iron core moves to the left to push the striker 42. When the coil is de-energized, the iron core moves to the right, and the striker 42 is reset. After the striker 42 is reset, there is a gap between the striker 42 and the guide tube 44. In addition, the trigger 41 can also be other devices that can push the striker 42 to move back and forth in the guide tube 44.

[0049] In this example, the present invention further includes a storage tube 43 for storing heterogeneous materials, the lower end of which is connected to the guide tube 44, and the storage tube 43 is vertically located on the guide tube 44. The inner diameter of the storage tube 43 is larger than the diameter of one heterogeneous material and smaller than the sum of the diameters of two heterogeneous materials, so that only one heterogeneous material can be placed inside the storage tube 43 in a transverse plane, and multiple heterogeneous materials are placed overlappingly in the storage tube 43. During the experiment, after the previous heterogeneous material is ejected, the next heterogeneous material automatically falls into the guide tube 44.

[0050] like Figure 2-5 As shown, the device for triggering nucleation also includes a fixing seat for stabilizing the guide tube 44 and the trigger 41. Specifically, the fixing seat includes a fixing plate A451, a fixing plate B452, a fixing frame 454 and a base 453. The lower surface of one end of the fixing plate B452 is vertically connected to the base 453, and the upper surface is vertically connected to the fixing plate A451. The upper surface of the other end of the fixing plate B452 is connected to the fixing frame 454. The trigger 41 is installed on the fixing frame 454; the end of the guide tube 44 close to the trigger 41 is vertically connected to the fixing plate A451. The base 453 is installed next to the lower electrode 23, and the axis of the guide tube 44 can pass through the suspended position of the sample 1.

[0051] After application, Figure 4 As shown, the sample 1 is located between the upper electrode 22 and the lower electrode 23 , the guide tube 44 , the striker 42 and the trigger 41 are all arranged horizontally, and the axis of the guide tube 44 passes through the sample 1 .

[0052] like Figure 4-Figure 9 As shown, in this example, the fixing seat of the device for triggering nucleation and the lower electrode 23 are both installed on the ceramic flange 21, and then placed in the sample cavity 24. The high-voltage electrode 25 is installed on the top of the sample cavity 24 and then connected to the instrument mounting platform 26. Finally, the neutron scattering electrostatic levitator 2 is placed in the scattering cavity 3 of the multi-physics spectrometer.

[0053] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. In-situ online neutron scattering measurement method for deep undercooling of amorphous alloys, characterized in that: include: A foreign substance is added to a suspended and deeply supercooled sample to trigger the nucleation of the sample; during this process, neutron scattering measurements are performed on the sample.

2. The method according to claim 1, characterized in that: The steps for the sample to reach a suspended and deeply supercooled state are: first suspending the solid sample in a neutron scattering electrostatic levitator, then heating the sample, and stopping heating after the sample becomes a melt; Allow the melt sample to cool to the target temperature.

3. The method according to claim 1, characterized in that The heterogeneous material is a molybdenum ball, a catalyst ball or a ball having the same composition as the sample.

4. The method according to claim 1, characterized in that: The diameter of the heterogeneity is less than or equal to 0.5 mm.

5. The in-situ online neutron scattering measurement method for deep undercooling of amorphous alloys according to claim 2, characterized in that: The target temperature is any temperature below the melting point of the sample.

6. The method according to claim 2, characterized in that After stopping heating the sample, allow the sample to cool freely to reach the target temperature.

7. A device for triggering nucleation, characterized in that: It comprises a trigger mechanism and a guide tube. The trigger mechanism is used in the method described in any one of claims 1 to 6 to provide power for adding heterogeneous matter into the sample for triggering nucleation of the sample. The guide tube is used to guide the heterogeneous matter to be ejected in a predetermined direction. After the trigger mechanism hits the heterogeneous matter, the heterogeneous matter is ejected from the guide tube and injected into the sample.

8. The device for triggering nucleation according to claim 7, characterized in that: The trigger mechanism includes a firing pin and a trigger, and the trigger is used to trigger the firing pin to hit the foreign matter in the guide tube.

9. The device for triggering nucleation according to claim 7 or 8, characterized in that: It also includes a storage tube for storing heterogeneous materials, the lower end of the storage tube is communicated with the guide tube, and the storage tube is vertically located on the guide tube.

10. The device for triggering nucleation according to claim 9, characterized in that: Also included are mountings for securing the guide tube and trigger.

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