Ultrasonic-assisted brazing method for crystalline / amorphous alloy brazing filler metal

Abstract

The invention relates to the technical field of brazing, and particularly discloses a crystalline / amorphous alloy brazing filler metal ultrasonic-assisted brazing method which comprises the following steps: respectively pretreating a steel substrate, crystalline / amorphous nickel-chromium brazing filler metal and diamond abrasive particles; the method comprises the steps that a steel substrate, crystalline / amorphous nickel-chromium brazing filler metal and diamond abrasive particles are sequentially bonded to form a sample of a sandwich structure, under the protective atmosphere, the sample is heated, ultrasonic action is applied to the sample after the preset brazing temperature is reached, the ultrasonic frequency of the ultrasonic action is 19-20.5 kHz, and the ultrasonic power is 520-780 W; and carrying out heat preservation and furnace cooling to obtain the brazed diamond. According to the method, ultrasonic parameters are regulated and controlled, and through the cavitation effect and the acoustic streaming effect generated by the ultrasonic action, the wettability of the brazing filler metal and the interface bonding strength are effectively promoted, brazing defect microcracks and holes are eliminated, the residual stress at the interface is effectively relieved, and compact and continuous Cr3C2 and Cr7C3 carbonized layers are formed.

Description

Technical Field

[0001] The invention relates to the technical field of brazing, and in particular to an ultrasonic-assisted brazing method for crystalline / amorphous alloy brazing materials. Background Art

[0002] Ultrasonic-assisted brazing is a new connection technology that introduces ultrasonic energy into the brazing process. It uses high-frequency mechanical vibration to break down the oxide film on the metal surface, enhance the wettability of the brazing material, and achieve high-quality and high-efficiency dissimilar metal connections.

[0003] Ultrasonic-assisted brazing (UAB) technology, as an innovative welding method in diamond brazing, has garnered widespread attention in recent years. Ultrasonic vibrations can effectively improve the wettability between the brazing filler metal and the diamond substrate, reducing the formation of defects such as oxide films and bubbles during the brazing process, thereby enhancing the mechanical properties and reliability of the joint. The high-frequency vibrations of ultrasound help enhance the interfacial bonding strength between the filler metal and the diamond, reducing the occurrence of cracks. However, existing technologies still face numerous challenges in practical application. For one thing, excessively high ultrasonic amplitudes can cause microcracks or damage to the brazed diamond interface, compromising weld quality. Furthermore, the cost of ultrasonic-assisted equipment is high, and the precision required to control vibration intensity is high. Excessively strong or weak vibrations can affect the weld quality. Furthermore, UAB technology still requires further optimization in terms of compatibility with different brazing fillers and the efficiency of vibration energy transfer. Therefore, while UAB brazing holds great potential, challenges in weld quality, equipment controllability, and applicability must be addressed to achieve wider industrial application. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide an ultrasonic-assisted brazing method for crystalline / amorphous alloy solders. By regulating ultrasonic parameters and utilizing the cavitation effect and acoustic streaming effect generated by ultrasonic action, the wettability of the solder and the interfacial bonding strength are effectively promoted, microcracks and holes in the brazing defects are eliminated, the residual stress at the interface is effectively relieved, and a dense and continuous Cr3C2 and Cr7C3 carbide layer is formed.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for ultrasonically assisted brazing of crystalline / amorphous alloy solder, which comprises the following steps: The steel substrate, crystalline / amorphous nickel-chromium brazing filler metal, and diamond abrasive grains are pretreated respectively; A steel substrate, crystalline / amorphous nickel-chromium brazing filler metal, and diamond abrasive grains are sequentially bonded to form a sandwich structure sample. The sample is heated under a protective atmosphere. After reaching a predetermined brazing temperature, an ultrasonic action is applied to the sample. The ultrasonic action has an ultrasonic frequency of 19-20.5 kHz and an ultrasonic power of 520-780 W. Keep warm and cool with the furnace to obtain brazed diamond.

[0006] As a further improvement of the above solution of the present invention, the crystalline / amorphous nickel-chromium solder contains the following components in percentage by mass: 70%-78% Ni, 10%-12% Cr, 3%-6% B, 3%-6% Si, and 4%-8% Fe.

[0007] As a further improvement of the above solution of the present invention, the heating adopts induction heating.

[0008] As a further improvement of the above solution of the present invention, the predetermined brazing temperature is 1000-1080°C.

[0009] As a further improvement of the above solution of the present invention, the ultrasonic action time is 5-10s.

[0010] As a further improvement of the above solution of the present invention, the insulation time is 5-15 minutes.

[0011] As a further improvement of the above solution of the present invention, the crystalline nickel-chromium solder and the amorphous nickel-chromium solder are in sheet form, the thickness of the crystalline nickel-chromium solder is 150-170 μm, and the thickness of the amorphous nickel-chromium solder is 40-50 μm.

[0012] As a further improvement of the above solution of the present invention, the pretreatment method of the steel substrate is: first, the brazing surface of the steel substrate is polished with sandpaper, and then the steel substrate is ultrasonically cleaned in acetone solution and ethanol solution for 5-15 minutes.

[0013] As a further improvement of the above-mentioned solution of the present invention, the pretreatment method of the crystalline / amorphous nickel-chromium solder is: first, the brazing surface of the crystalline / amorphous nickel-chromium solder is polished with sandpaper, and then the crystalline / amorphous nickel-chromium solder is ultrasonically cleaned in acetone solution and ethanol solution for 5-15 minutes.

[0014] As a further improvement of the above solution of the present invention, the pretreatment method of the diamond abrasive grains is: ultrasonically cleaning the diamond abrasive grains in acetone solution and ethanol solution for 5-15 minutes.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention, by regulating ultrasonic parameters and utilizing the cavitation and acoustic streaming effects generated by ultrasound, effectively improves brazing material wettability and interfacial bonding strength, eliminates microcracks and holes in brazing defects, effectively alleviates residual stress at the interface, and forms dense and continuous Cr3C2 and Cr7C3 carbide layers. Ultrasonic assistance enables high-performance brazing at lower temperatures, compared to crystalline brazing materials, due to the lower melting point and excellent wettability of amorphous brazing materials. Diamond crystal forms are intact, the number of corrosion pits is reduced, and diamond thermal damage is effectively reduced. By regulating ultrasonic parameters, the present invention optimizes diamond exposure and carbide layer morphology, significantly improving the overall performance of brazed joints. The method and process are stable and suitable for applications in high-performance diamond composite materials and tool preparation.

[0016] The present invention adopts ultrasonic-assisted induction brazing technology to successfully achieve metallurgical bonding of diamond abrasive grains and steel substrate using crystalline Ni-Cr brazing filler metal and amorphous Ni-Cr brazing filler metal under a protective atmosphere. The influence of ultrasonic process parameters (ultrasonic frequency, ultrasonic power) on the surface morphology characteristics and abrasive grain exposure of diamond is systematically studied, the mechanism of action of ultrasonic cavitation effect and acoustic streaming effect on interface bonding characteristics is clarified, and the influence of ultrasonic-assisted brazing on carbides on the diamond surface is revealed.

[0017] The ultrasonic parameters regulated by the present invention can make the solder fill the joint gap evenly, reduce the formation of holes on the brazing surface, effectively inhibit the excessive climbing of the amorphous solder on the side of the diamond, and the ultrasonic vibration can inhibit the capillary action to reduce the climbing phenomenon of the solder along the side of the diamond, thereby increasing the exposed height of the diamond. The acoustic streaming effect caused by ultrasonic vibration can increase the diffusion rate of the active element Cr in the liquid solder, which is more significant in the amorphous solder, forming a uniform and densely arranged carbide layer. The acoustic streaming effect effectively relieves the residual stress at the interface and greatly reduces the number of micro cracks. The present invention uses standard crystalline and amorphous Ni-Cr solders to ultrasonically assist the brazing of diamonds to generate two types of carbides, Cr3C2 and Cr7C3. The carbides are evenly covered on the diamond surface, and no micro cracks appear on the carbides on the diamond surface. The morphology of the carbides after brazing of the amorphous solder is finer and tighter than that of the crystalline solder. The cavitation effect generated by ultrasound promotes the rapid and uniform nucleation of carbides, and the acoustic streaming effect effectively breaks up the growing carbide grains, thereby forming fine and evenly distributed carbides. Secondly, ultrasonic vibration increases the nucleation rate of carbides, promotes the multi-point nucleation of chromium carbide, and thus inhibits the growth of individual carbides, ultimately obtaining finer chromium carbides. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Surface morphology of diamond brazed with crystalline Ni-Cr brazing filler metal prepared in Example 1-3; Figure 2This is a diagram showing the exposure of diamond brazed with crystalline Ni-Cr brazing filler metals prepared in Examples 1-3; Figure 3 This is the EDS image of diamond brazed with crystalline Ni-Cr brazing filler metal prepared in Example 1-3; Figure 4 This is a morphology of the carbide on the surface of the crystalline Ni-Cr brazing filler metal brazed diamond obtained in Example 1-3 after being etched with aqua regia; Figure 5 This is the XRD pattern of the surface carbide of the crystalline Ni-Cr brazing filler metal brazed diamond prepared in Example 1-3 after being etched with aqua regia; Figure 6 Surface morphology of diamond brazed with amorphous Ni-Cr brazing filler metal prepared in Example 4-6; Figure 7 This is a diagram showing the exposure of diamond brazed with amorphous Ni-Cr brazing filler metals prepared in Examples 4-6; Figure 8 This is the EDS image of diamond brazed with amorphous Ni-Cr solder prepared in Example 4-6; Figure 9 This is a morphology of the carbide on the surface of the amorphous Ni-Cr brazing filler metal brazed diamond prepared in Example 4-6 after being etched with aqua regia; Figure 10 This is the XRD pattern of the surface carbide of the amorphous Ni-Cr brazing filler metal brazed diamond prepared in Example 4-6 after being etched with aqua regia. DETAILED DESCRIPTION

[0019] To facilitate understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0021] Example 1 This embodiment provides a method for ultrasonically assisted brazing of crystalline alloy solder, which includes the following steps: A simple sandwich structure sample was formed by arranging a No. 45 steel block, a crystalline nickel-chromium brazing filler metal, and diamond abrasive grains in sequence from bottom to top. The sample was then placed flat in the groove of an ultrasonic horn tool head and protected by argon gas. Induction heating was applied, and the temperature was measured using an infrared device. After reaching 1080°C, ultrasonic treatment was applied at a frequency of 19-19.5 kHz, an ultrasonic power of 520 W, and an ultrasonic action time of 10 s. After a 5-minute hold, induction heating was terminated and the sample was cooled in the furnace to obtain a crystalline Ni-Cr brazing filler metal diamond sample (denoted as UB1). In this example, the crystalline nickel-chromium brazing filler metal used was a standard crystalline Ni-Cr brazing filler metal, comprising the following composition by weight: 78% Ni, 12% Cr, 3% B, 3% Si, and 4% Fe.

[0022] This embodiment uses existing ultrasonic brazing auxiliary equipment to perform ultrasonic assisted brazing. The structure of the ultrasonic brazing auxiliary equipment is well known and will not be described in detail here.

[0023] Example 2 The difference between this embodiment and embodiment 1 is that the ultrasonic power in this embodiment is 780 W. The crystalline Ni-Cr brazing material diamond sample prepared in this embodiment is denoted as UB2.

[0024] Example 3 The difference between this embodiment and embodiment 1 is that the ultrasonic frequency in this embodiment is 20-20.5 kHz. The crystalline Ni-Cr brazing material diamond sample prepared in this embodiment is denoted as UB3.

[0025] Test Example 1 (1) The crystalline Ni-Cr brazing diamond prepared in Examples 1-3 was characterized using a scanning electron microscope, and the following results were obtained: Figure 1 The scanning electron micrograph is shown.

[0026] Figure 1 a is the surface morphology of diamond brazed with crystalline Ni-Cr solder under ultrasonic conditions of 19-19.5 kHz and 520 W of ultrasonic power in Example 1; Figure 1 It can be seen from a that the crystal form of the diamond in Example 1 is relatively complete and the number of surface corrosion pits is relatively small, but holes are seen on the brazing surface. This is because induction heating is different from molybdenum strip heating. The induction heating rate is faster and the heating time is shorter. The metal binder has no time to escape and cools quickly, thus forming holes on the brazing surface.

[0027] Figure 1 b is the surface morphology of diamond brazed with crystalline Ni-Cr brazing filler metal in Example 2 under ultrasonic conditions of 19-19.5 kHz and 780 W ultrasonic power; Figure 1As can be seen from Figure b, when the ultrasonic frequency is kept constant and the ultrasonic power is increased to 780W, it can be observed that the number of pores on the brazing surface decreases. This difference can be attributed to the significant acoustic streaming effect and cavitation effect as the ultrasonic power increases. The ultrasonic wave propagates and oscillates in the liquid solder, promoting the discharge of bubbles, making the solder evenly filled and reducing the formation of pores.

[0028] Figure 1 c is the surface morphology of diamond brazed with crystalline Ni-Cr solder under ultrasonic conditions of 20-20.5kHz and 520W of ultrasonic power in Example 3; Figure 1 b It can be seen that when the ultrasonic power is kept unchanged and the ultrasonic frequency is increased, it is found that the increase in ultrasonic frequency can still reduce the formation of holes, but the brazing surface is relatively rough.

[0029] (2) Using an ultra-depth microscope, a side view of the crystalline Ni-Cr brazing material brazed diamond obtained in Example 1-3 was taken, and the following was obtained: Figure 2 The exposure map shown in Figure 2 is shown in Figure 2. Figure 2 It can be seen that the diamonds brazed by ultrasonic assisted brazing all have a relatively high exposed height. The acoustic streaming effect generated by ultrasonic vibration can accelerate the convection of molten brazing material, effectively inhibiting the excessive accumulation of brazing material on the side of the diamond. In addition, ultrasonic energy can inhibit the climbing of brazing material along the side of the diamond caused by capillary action.

[0030] (3) EDS test was performed on the crystalline Ni-Cr brazing filler metal brazing diamond prepared in Example 1-3. The results are as follows: Figure 3 shown.

[0031] Figure 3 a is the EDS image of the crystalline Ni-Cr brazing filler metal brazing diamond prepared in Example 1. It can be found that in Example 1, obvious bright stripes of Cr elements are seen at the interface between the brazing filler metal and the diamond, indicating that a large amount of Cr elements are enriched in this area and form a carbide layer with the C element; the line scan results at the interface prove that the thickness of the formed carbide layer is about 2.33μm.

[0032] Figure 3 b is an EDS image of diamond brazed with crystalline Ni-Cr brazing filler metal, obtained in Example 2. Increasing the ultrasonic power from 520W to 780W while maintaining the same ultrasonic frequency clearly reveals a denser carbide layer at the interface, with the thickness decreasing from 2.33μm to 2.19μm. This is likely due to the fact that ultrasonic vibration reduces the accumulation and dramatic rise of the brazing filler metal on the diamond's lateral surface, but has little effect on the carbide layer thickness.

[0033] Figure 3Figure c is an EDS image of diamond brazed with crystalline Ni-Cr brazing filler metal prepared in Example 3. It can be seen that when the ultrasonic frequency is increased to 20-20.5 kHz and the ultrasonic power remains unchanged, the size of the carbide layer at the interface decreases but remains dense, with a thickness of approximately 2.01 μm. Thus, as the ultrasonic power or frequency increases, it is found that the effect of ultrasonic power and frequency on the thickness of the carbide layer is small, and it tends to be almost stable.

[0034] (4) The crystalline Ni-Cr brazing filler metal obtained in Example 1-3 was etched with aqua regia to braze diamond, and the brazing filler metal layer on the diamond surface was removed to facilitate observation of the carbide on the diamond surface. The carbide on the diamond surface was then characterized using a scanning electron microscope, and the following was obtained: Figure 4 The morphology of diamond carbide brazed with crystalline Ni-Cr brazing filler metal is shown.

[0035] Figure 4 Figure c is the carbide morphology of the diamond surface brazed with crystalline Ni-Cr solder in Example 1. It can be seen that under the ultrasonic frequency of 19.5-19 kHz and the power of 520 W, the carbides present two morphologies: cylindrical and fine needles. In addition, the size of the carbides is uneven and distributed randomly on the diamond surface.

[0036] Figure 4 b is the carbide morphology of the diamond surface brazed with crystalline Ni-Cr solder in Example 2. It can be seen that when the ultrasonic frequency remains unchanged and the power is increased to 780W, the carbide is tightly covered on the diamond surface. The morphology of the carbide is a needle-shaped carbide structure of uniform size, and there are almost no microcracks on the carbide surface.

[0037] Figure 4 Figure c is the carbide morphology of the diamond surface brazed with crystalline Ni-Cr solder in Example 3. It can be seen that when the ultrasonic power remains unchanged and the frequency is increased to 20-20.5 kHz, the carbides are still tightly covered on the diamond surface. From the local magnified image of the carbides, the carbides still appear uneven in size, but the situation is better than that of Examples 1-2, indicating that the influence of ultrasonic assisted brazing power on the carbide morphology is more significant.

[0038] (5) In order to detect the types of carbides on the surface of diamond brazed by ultrasonic-assisted crystalline Ni-Cr solder, micro-area XRD test was performed on the carbides on the surface of diamond after aqua regia etching in Example 1-3. The results are as follows: Figure 5 As shown. Figure 5 It can be seen that no matter with the increase of ultrasonic power or frequency, Cr3C2 and Cr7C3 are the main carbides generated, indicating that the change of ultrasonic power and frequency will not affect the change of the type of carbides on the diamond surface. The formation of these two carbides ensures the high-strength grip of the brazing material on the diamond.

[0039] Example 4 This embodiment provides an ultrasonic-assisted brazing method for an amorphous alloy solder, which includes the following steps: A simple sandwich sample was formed by arranging a No. 45 steel block, an amorphous nickel-chromium brazing filler metal, and diamond abrasive grains in a sequential order from bottom to top. The sample was then placed flat in the groove of an ultrasonic horn tool head and protected by argon gas. Induction heating was applied, and the temperature was measured using an infrared device. After reaching 1000°C, ultrasonic treatment was applied at a frequency of 19-18.5 kHz, an ultrasonic power of 520 W, and an ultrasonic exposure time of 10 s. After a 5-minute hold, induction heating was terminated and the sample was cooled in the furnace to obtain an amorphous Ni-Cr brazing filler metal-diamond sample (denoted as UBA1). In this example, the amorphous nickel-chromium brazing filler metal used was a standard amorphous Ni-Cr brazing filler metal, comprising the following composition by weight: 78% Ni, 12% Cr, 3% B, 3% Si, and 4% Fe.

[0040] Example 5 The difference between this embodiment and embodiment 4 is that the ultrasonic power in this embodiment is 650 W. The amorphous Ni-Cr brazing diamond sample obtained in this embodiment is denoted as UBA2.

[0041] Example 6 The difference between this embodiment and embodiment 4 is that the ultrasonic power in this embodiment is 780 W. The amorphous Ni-Cr brazing diamond sample obtained in this embodiment is denoted as UBA3.

[0042] Test Example 2 (1) Scanning electron microscopy was used to characterize the amorphous Ni-Cr brazing diamond prepared in Examples 4-6, and the following results were obtained: Figure 6 The scanning electron microscope image shown. Figure 6 It can be seen that: unlike the crystalline solder, there are almost no holes on the surface of the diamond after brazing in Examples 4-6. Under the action of ultrasound, the fluidity of the solder is enhanced. It can be seen from the blue box that the brazing surface becomes dense and smooth, but the increase in ultrasonic power has no significant effect on the brazing surface. This is because the melting point of the amorphous solder is low, and the lower brazing temperature causes less thermal damage to the diamond; secondly, the amorphous solder itself has good wettability, and ultrasonic vibration can promote the diffusion of the active element Cr in the solder, forming a continuous carbide layer. Through the previous research, we know that the generated carbide layer can effectively hinder the dissolution of carbon atoms into the solder and reduce the formation of corrosion pits. Therefore, the number of diamond corrosion pits after brazing is less than that of the crystalline solder, and the crystal form is more complete.

[0043] (2) Using an ultra-depth microscope, a side view of the amorphous Ni-Cr brazing material brazed diamond obtained in Example 4-6 was taken, and the following was obtained: Figure 7Exposure diagram shown.

[0044] The traditional Ni-Cr amorphous solder has a very significant wettability for diamond. The amorphous solder will significantly climb on the side of the diamond. Even if the holding time is too long, the solder will wrap around the diamond, affecting the exposed height of the diamond and thus affecting the processing performance of the diamond. When the ultrasonic frequency remains unchanged, the ultrasonic power is increased, and the acoustic streaming effect is significant. The exposure of the diamond increases with the increase of ultrasonic power. Figure 7 As shown in Figure c, at an ultrasonic power of 780W, the diamond's exposure reached 65% of its height. Research indicates that an optimal diamond exposure of 40-50% is achieved. Excessively high exposure reduces the brazing material's grip on the diamond abrasive, making it prone to shedding under extreme working conditions. Therefore, overall, an ultrasonic frequency of 19-19.5kHz and an ultrasonic power of 650W achieve optimal brazing results, minimizing diamond thermal damage and maintaining high diamond exposure.

[0045] (3) EDS test was performed on the amorphous Ni-Cr brazing filler metal brazed diamond obtained in Example 4-6. The results are as follows: Figure 8 shown.

[0046] from Figure 8 It can be found that compared with crystalline solder, the interface of amorphous solder brazing forms more continuous and bright Cr element strips. This is attributed to the fact that the amorphous solder itself can melt and spread uniformly, and the elements in the solder diffuse evenly. Secondly, ultrasonic vibration accelerates the diffusion rate of Cr elements in the solder, which is beneficial to improving the interface bonding strength. With the continuous increase of ultrasonic power, the brazing interface of amorphous solder gradually transforms into a smooth interface. The carbides at the interface are uniform and small, and a uniform and densely arranged carbide layer is formed near the joint. In particular, Figure 8 As shown in Figure b, at an ultrasonic power of 650W, no holes were found at the brazing interface, and the number of microcracks was greatly reduced. Microcracks are caused by large residual stresses at the interface during the brazing process. Ultrasonic-assisted brazing can effectively alleviate residual stresses at the interface. The cavitation effect reduces the formation of holes during induction brazing. The acoustic streaming effect allows the brazing material to fully fill the joint gap, reducing local stress concentration and residual stress after brazing. When the ultrasonic power is increased from 520W to 650W, the thickness of the carbide layer decreases from 3.39μm to 2.72μm, a 19% decrease. However, as the ultrasonic power is further increased, the length of the microcracks at the interface increases, and the thickness of the carbide layer tends to be basically stable.

[0047] (4) The amorphous Ni-Cr brazing filler metal prepared in Example 4-6 was etched with aqua regia to braze the diamond, and the brazing filler metal layer on the diamond surface was removed to facilitate the observation of the carbide on the diamond surface. The carbide on the diamond surface was then characterized using a scanning electron microscope, and the following was obtained: Figure 9 The morphology of diamond carbide brazed with amorphous Ni-Cr brazing filler metal is shown.

[0048] from Figure 9 It can be seen that when the ultrasonic frequency is 19-19.5kHz and the ultrasonic power is 650W, the morphology of the carbides after brazing is finer and denser than that of crystalline brazing filler metals. The carbides are evenly covered on the diamond surface, which helps prevent the expansion of carbide cracks. This may be due to the cavitation effect prompting more carbides to nucleate quickly and evenly, and the acoustic streaming effect effectively breaking up the growing carbide grains, forcing them to split into smaller particles, thereby forming fine and evenly distributed carbides. Secondly, the high-frequency vibration of the ultrasound increases the nucleation rate of carbides, promoting the multi-point nucleation of chromium carbide, resulting in the formation of a large number of carbides in a short period of time, thereby inhibiting the growth of individual carbide particles and ultimately obtaining finer chromium carbides.

[0049] (5) In order to detect the types of carbides on the surface of diamond brazed by ultrasonic-assisted amorphous Ni-Cr solder, micro-area XRD test was performed on the carbides on the surface of diamond after aqua regia etching in Examples 4-6. The results are as follows: Figure 10 As shown. Figure 10 It can be seen that the carbides on the diamond surface in Examples 4-6 are mainly Cr3C2 and Cr7C3, indicating that during the ultrasonic-assisted brazing process, both standard crystalline and amorphous Ni-Cr solders generate two types of carbides, Cr3C2 and Cr7C3, and the formation of carbides is unrelated to the ultrasonic process parameters and the crystalline or amorphous properties of the solder.

[0050] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for ultrasonically assisted brazing of crystalline / amorphous alloy solder, characterized in that: It includes the following steps: The steel substrate, crystalline / amorphous nickel-chromium brazing filler metal, and diamond abrasive grains are pretreated respectively; A steel substrate, crystalline / amorphous nickel-chromium brazing filler metal, and diamond abrasive grains are sequentially bonded to form a sandwich structure sample. The sample is heated under a protective atmosphere. After reaching a predetermined brazing temperature, an ultrasonic action is applied to the sample. The ultrasonic action has an ultrasonic frequency of 19-20.5 kHz and an ultrasonic power of 520-780 W. Keep warm and cool with the furnace to obtain brazed diamond.

2. The ultrasonic-assisted brazing method for crystalline / amorphous alloy solder according to claim 1, characterized in that: The crystalline / amorphous nickel-chromium brazing filler metal comprises the following components in percentage by mass: 70%-78% Ni, 10%-12% Cr, 3%-6% B, 3%-6% Si, and 4%-8% Fe.

3. The ultrasonic-assisted brazing method for crystalline / amorphous alloy solder according to claim 1, characterized in that: The heating adopts induction heating.

4. The ultrasonic-assisted brazing method for crystalline / amorphous alloy solder according to claim 1, characterized in that: The predetermined brazing temperature is 1000-1080°C.

5. The ultrasonic-assisted brazing method for crystalline / amorphous alloy solder according to claim 1, characterized in that: The ultrasonic action time is 5-10s.

6. The ultrasonic-assisted brazing method for crystalline / amorphous alloy solder according to claim 1, characterized in that: The insulation time is 5-15 minutes.

7. The ultrasonic-assisted brazing method for crystalline / amorphous alloy solder according to claim 1, characterized in that: The crystalline nickel-chromium solder and the amorphous nickel-chromium solder are in sheet form. The thickness of the crystalline nickel-chromium solder is 150-170 μm, and the thickness of the amorphous nickel-chromium solder is 40-50 μm.

8. The ultrasonic-assisted brazing method for crystalline / amorphous alloy solder according to claim 1, characterized in that: The pretreatment method of the steel substrate is: firstly, the brazing surface of the steel substrate is polished with sandpaper, and then the steel substrate is ultrasonically cleaned in acetone solution and ethanol solution in sequence for 5-15 minutes.

9. The ultrasonic-assisted brazing method for crystalline / amorphous alloy solder according to claim 1, characterized in that: The pretreatment method of the crystalline / amorphous nickel-chromium solder is as follows: firstly, the brazing surface of the crystalline / amorphous nickel-chromium solder is polished with sandpaper, and then the crystalline / amorphous nickel-chromium solder is ultrasonically cleaned in acetone solution and ethanol solution for 5-15 minutes.

10. The ultrasonic-assisted brazing method for crystalline / amorphous alloy solder according to claim 1, characterized in that: The pretreatment method of the diamond abrasive grains is: ultrasonically cleaning the diamond abrasive grains in an acetone solution and an ethanol solution for 5-15 minutes.

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