Re-toughening method of metallic glass

Abstract

The invention provides a metal glass re-toughening method, and relates to the technical field of amorphous alloy mechanical property improvement, and the metal glass re-toughening method comprises the following steps: carrying out current treatment on relaxation-state metal glass, heating the relaxation-state metal glass to a first set temperature, and then carrying out quenching treatment; wherein the first set temperature is lower than the glass transition temperature Tg of the metal glass. It needs to be explained that the relaxation state (aging state) metal glass is subjected to energizing treatment, so that the relaxation state (aging state) metal glass is rapidly heated to a higher temperature, at the moment, the memory effect can be activated, the free volume content in the metal glass is increased to a certain extent, and the energy state of the metal glass is improved; subsequently, rapid cooling by quenching is performed such that the increased free volume is retained, achieving rejuvenation of the metallic glass after aging.

Description

Technical Field

[0001] The invention belongs to the technical field of improving the mechanical properties of metallic glass, and particularly relates to a re-toughening method for metallic glass. Background Art

[0002] Metallic glass, also known as amorphous alloy, has attracted widespread attention due to its outstanding mechanical properties (including extremely high strength, high elastic limit, and excellent friction and wear resistance), and has been widely used in many fields such as electronics, aviation, aerospace, medical devices, and microelectronics.

[0003] Because metallic glass is obtained by rapidly cooling a molten liquid, it retains residual stress. Therefore, prior to use, metallic glass products must be annealed below the glass transition temperature (Tg) to eliminate this residual stress. However, annealing can cause the metallic glass to age, a process known as relaxation (a decrease in its energy state). Aging can easily lead to embrittlement of metallic glass, severely hindering its practical application as a structural material. Therefore, in order to reuse aged metallic glass, a new method for re-toughening aged metallic glass is urgently needed, which would greatly promote its large-scale application.

[0004] Rejuvenation, also known as rejuvenation, has been proven to be an effective approach to addressing the aforementioned issues. Research has shown that various methods, including plastic deformation, elastic loading, irradiation, and low-temperature thermal cycling, can achieve rejuvenation of metallic glasses. However, these methods are primarily applicable to freshly prepared cast metallic glasses and are not suitable for rejuvenation of aged metallic glasses. In practice, metallic glasses are typically annealed, not cast, and therefore, rejuvenated. Therefore, it is crucial to address the rejuvenation of aged metallic glasses. Prior art discloses rejuvenation of aged metallic glasses through annealing, thereby restoring the ductility (and, consequently, toughness) of annealed metallic glasses. However, annealing for rejuvenation of aged metallic glasses presents the following challenges: conventional annealing furnaces have slow heating rates and significant size effects. When heating large samples, the temperature distribution is uneven, resulting in the exterior temperature quickly reaching the rejuvenation temperature while the interior takes a long time to reach the rejuvenation temperature. Due to the prolonged exposure to high temperatures on the exterior, re-aging is inevitable, leading to poor rejuvenation and, consequently, poor re-toughening of the metallic glass. Summary of the Invention

[0005] Therefore, the present invention provides a method for re-toughening metallic glass, which can solve the problem of poor re-toughening effect of metallic glass in the prior art.

[0006] In order to solve the above problems, the present invention provides a method for re-toughening metallic glass, comprising the following steps: performing a current treatment on the relaxed metallic glass to heat the relaxed metallic glass to a first set temperature, and then performing a quenching treatment; Wherein, the first set temperature is lower than the glass transition temperature Tg of the metallic glass.

[0007] Furthermore, the first set temperature is 0.93-0.96Tg.

[0008] Furthermore, before the step of passing current through the relaxed metallic glass, the method further comprises: performing a current treatment on the cast metallic glass to heat the cast metallic glass to a second set temperature to obtain the relaxed metallic glass; Wherein, the second set temperature is 0.8-0.85Tg.

[0009] Furthermore, the cast metallic glass has a diameter of 2-4 mm and a length of 20-24 mm.

[0010] Furthermore, in the step of passing current through the cast metallic glass, the current is 12-18 A and the time is 4.5-5.5 hours.

[0011] Furthermore, in the step of passing current through the relaxed metallic glass, the current is 18-27 A and the time is 20-60 s.

[0012] Furthermore, before the step of subjecting the cast metallic glass to current treatment, the method further includes: subjecting the cast metallic glass to differential scanning calorimetry analysis to obtain the relaxation enthalpy ΔH1 of the cast metallic glass.

[0013] Furthermore, after the step of passing current through the cast metallic glass, the method further comprises: performing differential scanning calorimetry analysis on the relaxed metallic glass to obtain a relaxation enthalpy ΔH2 of the relaxed metallic glass; Among them, ΔH1>ΔH2.

[0014] Furthermore, after the quenching step, the method further includes: performing differential scanning calorimetry analysis on the metallic glass after the quenching to obtain a relaxation enthalpy ΔH3 of the metallic glass after the quenching; Among them, ΔH3>ΔH2; Preferably, ΔH3=20%ΔH1-40%ΔH1.

[0015] The present invention provides a method for toughening metallic glass, which has the following beneficial effects: 1. The present invention provides a method for re-toughening metallic glass, comprising the following steps: passing an electric current through the relaxed metallic glass to heat the relaxed metallic glass to a first set temperature, and then performing a quenching treatment; wherein the first set temperature is lower than the glass transition temperature Tg of the metallic glass. It should be noted that the present invention processes the relaxed (aged) metallic glass by passing an electric current through it, causing it to heat up rapidly to a higher temperature. At this time, the memory effect can be activated, thereby increasing the free volume content in the metallic glass to a certain extent and improving the energy state of the metallic glass. Subsequently, the increased free volume is retained through rapid cooling by quenching, thereby achieving the rejuvenation of the metallic glass after aging. The heating method is different from the traditional external heat conduction (such as annealing furnace heating). Instead, when the current is passed through the resistance inside the metallic glass sample, heat (Joule heat) is generated. There is no need to transfer heat from the surface to the inside through heat conduction, thus avoiding the temperature rise lag problem caused by heat conduction delay in traditional heating and greatly shortening the heating time. Moreover, the Joule heat is generated synchronously in each region inside the metallic glass sample, so the temperature distribution is more uniform from the beginning, reducing the temperature difference caused by heat conduction, and minimizing the size effect even in large-scale or complex geometric samples.

[0016] 2. Furthermore, the present invention subjects the cast metallic glass to a current treatment. Under the action of resistance, the sample temperature rises, causing the free volume in the metallic glass to annihilate, thereby reducing the energy state of the metallic glass and causing the metallic glass to age. The current treatment causes a rapid temperature rise, further improving the re-toughening efficiency of the metallic glass, while also releasing residual stress in the metallic glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. The drawings described below are merely exemplary. Those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.

[0018] Figure 1 Middle: (a) and (b) are schematic diagrams of current treatment in the metallic glass re-toughening method of the present invention and energy change diagrams in the conventional re-toughening method, respectively; Figure 2 Middle: (a) and (b) are DSC curves and energy evolution diagrams of as-cast metallic glasses, aged metallic glasses, and young metallic glasses of different sizes, respectively; Figure 3 Middle: (a)-(d) are the XRD curves of as-cast metallic glass, aged metallic glass and young metallic glass and the corresponding transmission electron microscopy images; Figure 4 Middle: (a), (b), and (c) are the hardness change curves, plastic strain curves, and compressive stress-strain curves of cast metallic glass, aged metallic glass, and young metallic glass, respectively; Figure 5 Nanoindentation creep behavior of as-cast metallic glass, aged metallic glass, and young metallic glass; Figure 6 Middle: (a)-(c) are DSC curves of the aging and rejuvenation processes of metallic glass achieved by heating in an annealing furnace (comparative example); (d) is a graph showing the relationship between the relaxation enthalpy of metallic glass and time during re-toughening (rejuvenation) using the method of the present invention and the existing method. DETAILED DESCRIPTION

[0019] To further illustrate the technical means and effects employed by the present invention to achieve its intended objectives, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention is provided in conjunction with the accompanying drawings and preferred embodiments. In the following description, different references to "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0020] The memory effect is widely present in amorphous materials. It refers to a process in which the energy or volume of an amorphous material first increases, then decreases, and finally reaches equilibrium during the second annealing process when it undergoes two-step heat treatment (first low temperature and then high temperature). Figure 1 (b) As shown. This process of energy or volume increase is called the memory effect, which is also a process of rejuvenation of metallic glass after the first step of heat treatment and aging. After this rejuvenation process, the energy state of the metallic glass, that is, the free volume content, will be restored to a certain extent. However, in the actual industrial application of metallic glass, in order to eliminate the residual stress caused by rapid cooling, annealing treatment is an inevitable measure to be taken. This process causes the metallic glass to age (energy reduction, free volume reduction), which in turn causes the metallic glass to become brittle, severely limiting the application of metallic glass. Based on this special background, we innovatively proposed to use the memory effect to perform a second step of heat treatment on the aged sample to improve the energy state of the metallic glass, thereby improving the mechanical properties of the metallic glass (achieving the re-toughening of the aged metallic glass). The specific plan is as follows: The present invention provides a method for re-toughening metallic glass, comprising the following steps: The cast metallic glass is subjected to a current treatment to obtain a metallic glass in a relaxed state (aged state); The specific steps are: Figure 1As shown in (a), copper wires are wrapped around the two ends of the cast metallic glass, and a DC power supply is used to energize the cast metallic glass. After maintaining a certain current for a certain period of time, the power is turned off, and the cast metallic glass is heated to a second set temperature of 0.8-0.85Tg. The obtained relaxed (aged) metallic glass is subjected to differential scanning calorimetry to obtain the relaxation enthalpy ΔH2 of the relaxed metallic glass. When the relaxation enthalpy ΔH2 of the cast metallic glass is less than ΔH1, it can be determined that the metallic glass has aged.

[0021] Then, the relaxed metallic glass is subjected to a current treatment and then to a quenching treatment to obtain a re-toughened metallic glass (i.e., a rejuvenated metallic glass); Specifically, this step involves wrapping a copper wire around both ends of the relaxed metallic glass and heating it again at a higher current. After a period of time, the current is turned off, with the current being approximately 1.5-2 times the current of the previous step. The relaxed metallic glass is heated to a first set temperature of 0.93-0.96Tg, and the sample is quickly placed in liquid nitrogen (or ice water, or an oil bath, or a salt bath) for quenching, thereby rejuvenating the metallic glass. The resulting relaxed (aged) metallic glass is subjected to differential scanning calorimetry to determine the relaxation enthalpy ΔH3 of the relaxed metallic glass. When ΔH3 > ΔH2, the aged metallic glass is considered to have been rejuvenated. Preferably, ΔH3 = 20% ΔH1 - 40% ΔH1. Tg is the glass transition temperature of the metallic glass.

[0022] It should be noted that the present invention processes the relaxed (aged) metallic glass by passing an electric current through it, causing it to heat up rapidly to a higher temperature. At this time, the memory effect can be activated, thereby increasing the free volume content in the metallic glass to a certain extent and improving the energy state of the metallic glass. Subsequently, the increased free volume is retained through rapid cooling by quenching, thereby achieving the rejuvenation of the metallic glass after aging. The heating method is different from the traditional external heat conduction (such as annealing furnace heating). Instead, when the current is passed through the resistance inside the metallic glass sample, heat (Joule heat) is generated. There is no need to transfer heat from the surface to the inside through heat conduction, thus avoiding the temperature rise lag problem caused by heat conduction delay in traditional heating and greatly shortening the heating time. Moreover, the Joule heat is generated synchronously in each region inside the metallic glass sample, so the temperature distribution is more uniform from the beginning, reducing the temperature difference caused by heat conduction, and minimizing the size effect even in large-scale or complex geometric samples.

[0023] Furthermore, the present invention subjects the cast metallic glass to a current-passing treatment. Under the action of resistance, the sample temperature rises, prompting the annihilation of the free volume in the metallic glass, thereby reducing the energy state of the metallic glass and causing aging of the metallic glass. The current-passing treatment causes a rapid temperature rise, further improving the re-toughening efficiency of the metallic glass, while also releasing the residual stress in the metallic glass.

[0024] When rejuvenating aged (relaxed) metallic glass, the current treatment raises the temperature to 0.93-0.96Tg, below the glass transition temperature (Tg) of the metallic glass, ensuring that the metallic glass remains solid and does not deform. The temperature is also high enough to generate sufficient free volume for a high degree of rejuvenation. When aging cast metallic glass through current treatment, raising the temperature to 0.8-0.85Tg ensures faster aging and avoids excessive temperatures that could lead to a supercooled liquid phase and disrupt the slow relaxation environment required for aging.

[0025] The current during the above-mentioned current-passing treatment is appropriately adjusted according to the size of the sample. When the diameter of the cast metallic glass is 2-4 mm and the length is 20-24 mm; in the step of current-passing treatment on the cast metallic glass: the current is 12-18 A, and the time is 4.5-5.5 hours; in the step of current-passing treatment on the relaxed metallic glass: the current is 18-27 A, and the time is 20-60 seconds.

[0026] The cast metallic glass is a metallic glass rod produced using an arc melting and casting system. The process involves the following steps: selecting a certain mass of various pure metal raw materials and ultrasonically cleaning them with alcohol for 2 minutes; selecting cylindrical pure copper molds of varying sizes, uniformly melting the cleaned raw materials in a crucible, and then casting them to produce metallic glass rods of varying sizes. The casting mold is selected with an appropriate diameter based on the raw material mass to ensure that the alloy melt fills the mold and produces a metallic glass rod with good surface quality. The resulting metallic glass rod is then polished to remove surface burrs and ultrasonically cleaned with alcohol to facilitate current flow.

[0027] In addition, the method for rejuvenating metallic glass based on the current-driven memory effect of the present invention has the following advantages over the prior art: (1) The process of the present invention is simple and applicable to all types of conductive metallic glasses and samples of any shape and size. It is non-destructive to the samples and has high industrial application value.

[0028] (2) The process of the present invention does not change the shape and amorphous structure of the metallic glass.

[0029] (3) The mechanical properties of the samples treated by this rejuvenation method are greatly improved, even better than those of the cast samples.

[0030] The present invention is further described below with reference to specific examples and comparative examples.

[0031] In the examples and comparative examples, the cast metallic glass was prepared by the following method: The single metals Zr, Cu, Ni, and Al with a purity higher than 99.9% are mixed according to a certain atomic percentage (Zr64.13Cu15.75Ni10.12Al10), and then melted in an arc melting furnace under the protection of high-purity argon. The melting is repeated 8 times to obtain alloy ingots; metallic glass rod samples (cast metallic glass) with diameters of 2mm, 3mm, and 4mm are obtained by copper mold suction casting or casting.

[0032] Example 1 This embodiment provides a method for re-toughening metallic glass, comprising the following steps: The steps are as follows: a copper wire is wrapped around the two ends of a cast metallic glass with a diameter of 2 mm and a length of 24 mm, and a DC power supply is applied for 5 hours and then disconnected to obtain a relaxed (aged) metallic glass; wherein the current is 12 A; A copper wire was then wrapped around both ends of the relaxed metallic glass. A DC power supply was applied for 20 seconds and then turned off, and the glass was then cooled in liquid nitrogen to obtain re-toughened metallic glass (i.e., rejuvenated metallic glass). The current was 18A.

[0033] Example 2 This embodiment provides a method for re-toughening metallic glass, comprising the following steps: The steps are as follows: a copper wire is wrapped around the two ends of a cast metallic glass with a diameter of 3 mm and a length of 20 mm, and a DC power supply is applied for 5 hours and then disconnected to obtain a relaxed (aged) metallic glass; wherein the current is 18 A; A copper wire was then wrapped around both ends of the relaxed metallic glass. A DC power supply was applied for 60 seconds and then turned off, and the glass was then cooled in liquid nitrogen to obtain re-toughened metallic glass (i.e., rejuvenated metallic glass). The current was 26A.

[0034] Example 3 This embodiment provides a method for re-toughening metallic glass, comprising the following steps: The steps are as follows: a copper wire is wrapped around the two ends of a cast metallic glass with a diameter of 4 mm and a length of 20 mm, and a DC power supply is applied for 5 hours and then disconnected to obtain a relaxed (aged) metallic glass; wherein the current is 18 A; A copper wire was then wrapped around both ends of the relaxed metallic glass. A DC power supply was applied for 60 seconds and then turned off, and the glass was then cooled in liquid nitrogen to obtain re-toughened metallic glass (i.e., rejuvenated metallic glass). The current was 27A.

[0035] Comparative Example 1 This comparative example provides a method for re-toughening metallic glass, comprising the following steps: The cast metallic glass with a diameter of 2 mm and a length of 4 mm was annealed at 557 K for 5 h to obtain the relaxed (aged) metallic glass. The relaxed (aged) metallic glass was annealed at 642 K for 90 seconds and then cooled in liquid nitrogen to obtain the re-toughened metallic glass (i.e., the rejuvenated metallic glass).

[0036] Comparative Example 2 This comparative example provides a method for re-toughening metallic glass, comprising the following steps: The cast metallic glass with a diameter of 2 mm and a length of 24 mm was annealed at 557 K for 5 h to obtain the relaxed (aged) metallic glass. The relaxed (aged) metallic glass was annealed at 642 K for 180 s and then cooled in liquid nitrogen to obtain the re-toughened metallic glass (i.e., the rejuvenated metallic glass).

[0037] Comparative Example 3 This comparative example provides a method for re-toughening metallic glass, comprising the following steps: The cast metallic glass with a diameter of 4 mm and a length of 20 mm was annealed at 557 K for 5 h to obtain the relaxed (aged) metallic glass. The relaxed (aged) metallic glass was annealed at 642 K for 420 s and then cooled in liquid nitrogen to obtain the re-toughened metallic glass (i.e., the rejuvenated metallic glass).

[0038] The corresponding parameters of the above embodiments and comparative examples are shown in Table 1.

[0039] Table 1

[0040] The performance energy and mechanical properties of the metallic glass obtained in the above examples and comparative examples were characterized. The results are as follows: Figures 2 to 6 shown.

[0041] in, Figure 2 The DSC curves and energy statistics of metallic glasses in different states. Figure 2As can be seen in (a)-(c), the as-cast sample exhibits a distinct exothermic peak before undergoing the glass transition, indicating a high-energy state. After the first current annealing step (12-18A, 5 h), the exothermic peak disappears, accompanied by the appearance of an endothermic peak, indicating that the sample has aged after the first current treatment. The aged sample is then subjected to a further treatment at a higher current (18-27A, 20-60 s). The endothermic peak of the amorphous sample disappears, while the exothermic peak reappears, indicating that the sample is now in a high-energy state. This second current annealing treatment achieves rejuvenation of the aged metallic glass. Figure 2 (d) Detailed display of the energy states of metallic glass samples in the as-cast, aged, and after different rejuvenation treatment times. It is clearly evident that the second current heat treatment increases the energy of the amorphous alloy. Furthermore, as the second current heat treatment duration increases, the energy state of the amorphous alloy first increases and then stabilizes. This initial energy increase during the second current heat treatment is a manifestation of the memory effect in metallic glass.

[0042] Figure 3 From the XRD patterns of metallic glasses in different states, it can be found that all samples show the typical bun peaks of amorphous alloys, and no crystal diffraction peaks are found. At the same time, the transmission electron microscope photos show the typical diffraction rings and disordered structures of amorphous alloys, indicating that the metallic glass still maintains a completely amorphous structure after current heat treatment.

[0043] Figure 4 The hardness and compression performance results of metallic glass in different states. Figure 4 (a) shows that the hardness of amorphous alloys will increase after aging, while rejuvenation will have the opposite effect, reducing their hardness. It can also be found that the hardness of metallic glass will soften after rejuvenation due to the current memory effect. Figure 4 (b) and (c) show the compressive stress-strain curves and plastic strain statistics of metallic glasses in different states, respectively. Aging significantly reduces the plasticity of metallic glasses, causing embrittlement of the amorphous alloy. Conversely, rejuvenation significantly improves the plasticity of metallic glasses. Under optimal conditions, the plasticity of the rejuvenation specimens is significantly better than that of the as-cast specimens. This demonstrates that utilizing the current-driven memory effect can not only significantly improve the plasticity of metallic glasses but can also be used to enhance the mechanical properties of aged metallic glasses.

[0044] Figure 5 Nanoindentation creep results for metallic glasses in different states. As can be seen, the as-cast amorphous alloy exhibits the worst creep performance, which improves after aging. The younger sample exhibits the best creep resistance.

[0045] Figure 6The DSC curves of metallic glasses in different states when the memory effect is activated by annealing furnace heating and the relationship between the relaxation enthalpy and time when the two heating methods are used for rejuvenation. From the DSC curves in Figures (a)-(c), it can be seen that the evolution trend of the DSC curves when the annealing furnace heating method is used for two-step annealing is different from that of the metallic glasses in different states. Figure 2 The DSC curves of the two-step current heating are consistent, indicating that annealing furnace heating can also activate the memory effect to achieve rejuvenation of aged metallic glass. However, it can also be seen that the DSC curve of the metallic glass after annealing furnace heating rejuvenation and the DSC curve of the cast metallic glass sample are in the glass transition region ( Figure 6 The dotted box in (a) does not overlap, indicating that while annealing heating causes the metallic glass to continue aging to a certain extent, this misalignment trend increases with increasing sample size, and an "overshoot" endothermic peak also appears. This indicates that while annealing heating activates the memory effect and rejuvenates the metallic glass (the low-temperature portion, corresponding to β relaxation), it inevitably leads to a certain degree of aging (high-temperature aging behavior within the glass transition region, corresponding to the α relaxation portion), which deteriorates the rejuvenation effect. In addition, as can be seen in Figure (d), the rejuvenation time required for current heating is relatively short and the degree of rejuvenation is relatively large.

[0046] For the aforementioned performance tests, compression specimens were prepared using the following method: Rod-shaped samples prepared in different states (as-cast, aged, and rejuvenated) in steps 1 and 2 were cut into cylindrical specimens with a 2:1 aspect ratio using a diamond cutter. The upper and lower surfaces of the specimens were then paralleled using #1000-#5000 sandpaper using a custom-made fixture, and then polished to a mirror finish. Nanoindentation creep specimens were prepared using the following method: Rod-shaped specimens in different states (as-cast, aged, and rejuvenated) were mounted in a transparent cold mounting material, then ground using a custom-made flat grinder on gauze papers of varying sizes (#4000-#5000). Finally, the specimens were polished using a 50 nm SiO2 suspension to a mirror finish.

[0047] It is easy for those skilled in the art to understand that, under the premise of no conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A method for toughening metallic glass, characterized in that: The following steps are involved: performing a current treatment on the relaxed metallic glass to heat the relaxed metallic glass to a first set temperature, and then performing a quenching treatment; Wherein, the first set temperature is lower than the glass transition temperature Tg of the metallic glass.

2. The method for re-toughening metallic glass according to claim 1, wherein: The first set temperature is 0.93-0.96Tg.

3. The method for re-toughening metallic glass according to claim 1, wherein: Before the step of applying current to the relaxed metallic glass, the method further comprises: performing a current treatment on the cast metallic glass to heat the cast metallic glass to a second set temperature to obtain the relaxed metallic glass; Wherein, the second set temperature is 0.8-0.85Tg.

4. The method for re-toughening metallic glass according to claim 3, wherein: The cast metallic glass has a diameter of 2-4 mm and a length of 20-24 mm.

5. The method for re-toughening metallic glass according to claim 4, characterized in that: In the step of passing current through the cast metallic glass, the current is 12-18 A and the time is 4.5-5.5 hours.

6. The method for re-toughening metallic glass according to claim 5, characterized in that: In the step of passing current through the relaxed metallic glass, the current is 18-27 A and the time is 20-60 s.

7. The method for re-toughening metallic glass according to claim 3, wherein: Before the step of performing current treatment on the cast metallic glass, the method further includes: performing differential scanning calorimetry analysis on the cast metallic glass to obtain the relaxation enthalpy ΔH1 of the cast metallic glass.

8. The method for re-toughening metallic glass according to claim 7, wherein: After the step of passing current through the cast metallic glass, the method further includes: performing differential scanning calorimetry analysis on the relaxed metallic glass to obtain a relaxation enthalpy ΔH2 of the relaxed metallic glass; Among them, ΔH1>ΔH2.

9. The method for re-toughening metallic glass according to claim 7, wherein: After the quenching step, the method further includes: performing differential scanning calorimetry analysis on the quenched metallic glass to obtain a relaxation enthalpy ΔH3 of the quenched metallic glass; Among them, ΔH3>ΔH2.

10. The method for re-toughening metallic glass according to claim 7, wherein: ΔH3=20%ΔH1-40%ΔH1.

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