A gradient structure Ag / FeMnCrNi laminated composite material and a preparation method thereof

Abstract

The application discloses a gradient structure Ag / FeMnCrNi layered composite material and a preparation method, and belongs to the field of metal surface modification. The layered composite material comprises Ag layers and FeMnCrNi layers arranged alternately, the thickness of the Ag layers and the FeMnCrNi layers in one modulation period is the same, and the thickness of the Ag layers and the FeMnCrNi layers in each modulation period is gradiently increased. The Ag layers and the FeMnCrNi layers are alternately deposited by direct current magnetron sputtering using an Ag target and a FeMnCrNi target to obtain the gradient structure Ag / FeMnCrNi composite material. The method utilizes the design idea of the multi-scale gradient non-uniform structure, combines the multi-principal element effect of the HEA with the constraint effect of the gradient layer interfacial heterogeneity, constructs a soft and hard heterostructure gradient, and in the plastic deformation process, the strain gradient is generated due to the different deformations of the soft and hard components, new dislocation structures are activated, the mechanical behavior of the whole metal layered composite material is affected, and finally the breakthrough of the mechanical properties is realized.

Description

Technical Field

[0001] This invention relates to the field of metal surface modification, specifically to a gradient structure Ag / FeMnCrNi nanolayered material and its preparation method. Background Technology

[0002] The development of 5G information technology has accelerated the revolution of artificial intelligence and the Internet of Things (IoT). Recently, IoT systems have been widely applied in defense, transportation, healthcare, and daily life, becoming an indispensable part of national technological development. These IoT systems are composed of numerous micro / nano devices (MEMS / NEMS) that form their sensing "neurons." Among them, the core structure of micro / nano devices—metal thin-film interconnect materials—demonstrates its important role and application advantages in the large-scale manufacturing of printed circuit boards and the miniaturization of integrated circuits due to its excellent mechanical and electrical properties.

[0003] However, with the recent trends of miniaturization, low loss, and high precision in microelectronic devices, the complex and precise manufacturing process inevitably involves multi-field coupling effects such as force and heat. This can lead to deformation / instability of critical internal components, performance degradation, and ultimately failure, severely impacting the service life of microelectronic devices. Metal thin film materials remain hampered by this challenge. Therefore, developing mechanically stable and reliable metal thin film structural materials for micro and nano devices is of paramount importance for driving the development of the microelectronics industry.

[0004] Currently, the mechanical properties of traditional metal multilayer films have reached a bottleneck, necessitating disruptive coating designs to meet the requirements of complex service environments. Recently, high-entropy alloys (HEAs), as a novel type of multi-principal-element alloy, exhibit four unique effects in terms of structure, composition, thermodynamics, and kinetics due to their unique microstructure, thus demonstrating excellent mechanical properties. Simultaneously, the design concept of multi-scale gradient non-uniform structures is considered an effective way to achieve a good balance between strength and toughness. By controlling the grain size / layer thickness gradient or heterogeneous interface constraints, gradient microstructure control can be achieved across multiple characteristic dimensions from the nanoscale to the macroscale, optimizing overall mechanical properties. If high-entropy alloys and metals can be alternately deposited using magnetron sputtering to form metal-high-entropy alloy gradient metal layered composite materials, the properties of both metal and high-entropy alloys can be coupled into one material, introducing the constraint effect of gradient interlayer heterogeneous interfaces. This holds great potential for achieving excellent mechanical properties and is expected to break through the mechanical performance bottleneck of traditional metal nanolayer films. Therefore, it is necessary to study a method for preparing metal / high-entropy alloy nanolayered composite materials with different gradient structures to fill this gap. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a gradient structure Ag / FeMnCrNi layered composite material and its preparation method. By coupling a low-dimensional heterostructure with the unique multi-principal element effect of HEA and controlling the thickness gradient of functional unit layers, a uniform, dense, and strongly interfacially bonded gradient structure Ag / FeMnCrNi multilayer film with excellent mechanical properties is prepared.

[0006] This invention is achieved through the following technical solution:

[0007] A gradient structure Ag / FeMnCrNi composite material includes alternating Ag layers and FeMnCrNi layers. The thickness of the Ag layer and FeMnCrNi layer is the same in one modulation cycle, and the thickness of the Ag layer and FeMnCrNi layer increases in each modulation cycle.

[0008] Preferably, the Ag layer of the gradient structure Ag / FeMnCrNi layered composite material is crystalline with columnar crystal morphology, and the FeMnCrNi layer has an FCC structure.

[0009] When the thickness of the FeMnCrNi layer on the surface of the composite material is less than 50 nm, the internal structure of the FeMnCrNi layer is a two-phase structure in which a small number of crystals are "embedded" in amorphous material. When the thickness of the FeMnCrNi layer on the surface of the composite material is greater than 50 nm, the internal structure of the FeMnCrNi layer is an amorphous structure.

[0010] Preferably, the Ag / FeMnCrNi composite material has a thickness of 1.4μm-1.5μm and a hardness of 2.92GPa-3.46GPa.

[0011] A method for preparing a gradient structure Ag / FeMnCrNi composite material includes the following steps:

[0012] Step 1: Clean the substrate and remove the oxide film on the surface.

[0013] Step 2: Use Ag target and FeMnCrNi target to alternately deposit Ag layer and FeMnCrNi layer by DC magnetron sputtering. The thickness of Ag layer and FeMnCrNi target is the same in one modulation cycle. The thickness gradient of Ag layer and FeMnCrNi layer increases in each modulation cycle until the total thickness of composite material reaches the preset thickness. Cool to room temperature with furnace to obtain Ag / FeMnCrNi composite material.

[0014] Preferably, the method for cleaning the substrate and removing the oxide film on the surface in step 1 is as follows:

[0015] After polishing the substrate, ultrasonic cleaning is performed. After the substrate dries, acid pickling is performed to remove the oxide film on the substrate surface.

[0016] Preferably, the change in thickness gradient in step 2 is less than or equal to 25 nm.

[0017] Preferably, in step 2, both the Ag target and the FeMnCrNi target use a DC power supply with a power of 200W, a deposition gas pressure of 0.7Pa, and a silicon substrate rotation speed of 15r / min during the magnetron sputtering co-sputtering deposition process.

[0018] Preferably, the atomic ratio of the FeMnCrNi target is: 30.43 at.%, Fe - 20.46 at.%, Mn - 22.29 at.%, Cr - 26.82 at.%Ni.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] This invention provides a gradient-structured Ag / FeMnCrNi layered composite material. The Cantor alloy, by removing Co, forms a quaternary FCC structure—FeMnCrNi alloy—which exhibits excellent deformability and ductility. Metallic Ag has low stacking fault energy and readily generates twins during growth, dominating plastic deformation. This application prepares Ag and FeMnCrNi alloy into a layered composite material, forming a unique layered structure and a high-density heterogeneous interface. Simultaneously, utilizing the design concept of a multi-scale gradient non-uniform structure, the multi-principal element effect of the HEA (Heterogeneous Aperture Equivalent) is combined with the constraint effect of the gradient interlayer heterogeneous interface to construct a gradient of soft and hard heterogeneous structures. During plastic deformation, the non-simultaneous deformation of the soft and hard components generates a strain gradient, activating new dislocation structures in the material, thereby affecting the overall mechanical behavior of the metallic layered composite material and ultimately achieving a breakthrough in mechanical properties.

[0021] The preparation method of Ag / FeMnCrNi layered composite material of the present invention adjusts the interface structure of Ag / FeMnCrNi gradient nanolayered composite material by controlling the deposition time. During the deposition process, the collision probability between Fe, Mn, Cr and Ni atoms sputtered from the FeMnCrNi high-entropy alloy target is high, and the deposition energy to the matrix is ​​relatively high, thus forming a partially metastable amorphous structure. When the thickness of the surface layer of the gradient structure composite material is less than 50 nm, the FeMnCrNi layer is a two-phase structure of crystal "embedded" in amorphous material. When the thickness of the surface layer of the gradient structure composite material is greater than 50 nm, the internal structure of the FeMnCrNi layer is amorphous, and the Ag atoms sputtered from the Ag target deposit to form a crystalline layer. The interlayer interface structure of all composite materials is a crystalline-amorphous interface, and the interface structure is stable and does not change. By changing the deposition time of the two targets during the deposition process, Ag / FeMnCrNi gradient nanolayered composite materials with different thickness gradients can be obtained. The thickness of functional building blocks and the interface of laminated materials are important factors affecting their mechanical properties and deformation mechanisms. Changes in layer thickness gradient can construct structural gradients by controlling the layer thickness. Under external load, due to structural differences, non-uniform plastic deformation occurs, leading to strain gradients that activate / influence dislocation structures. As the layer thickness gradient increases, the structural gradient gradually increases, resulting in significant additional strengthening effects. The hardness of the composite material increases to a peak value, with a layer thickness gradient of Δh = 5 nm. Subsequently, as the gradient continues to increase, due to the increased volume fraction of large-scale layers (>80 nm) in the multilayer film and the gradual decrease in heterogeneous interface density, the hardness gradually decreases from the peak value to a stable state. In this application, the sample with Δh = 5 nm exhibits the highest hardness, while the Ag / FeMnCrNi gradient nanolayered composite material with Δh = 10-25 nm shows similar hardness.

[0022] Furthermore, after deposition, the material is placed naturally in the high-vacuum coating chamber for furnace cooling to stabilize the Ag-FeMnCrNi layer interface structure, prevent the nanolayer material from falling off or breaking due to differences in the thermal expansion coefficients of the film and the substrate or internal stress, and prevent oxidation caused by contact with air at high temperatures. Attached Figure Description

[0023] Figure 1 The diagram shows the gradient laminated structures of Ag / FeMnCrNi layered composite materials with different gradient structures prepared in Examples 1 to 5.

[0024] Figure 2 The images show the TEM cross-sectional view (with embedded EDS surface scan elemental content table) and XRD pattern of the FeMnCrNi monolayer film sputtered by magnetron sputtering according to the present invention.

[0025] Figure 3XRD patterns of Ag / FeMnCrNi layered composite materials with different gradient structures prepared by magnetron sputtering in this invention.

[0026] Figure 4 This is a TEM cross-sectional view of a typical gradient structure Ag / FeMnCrNi layered composite material prepared by magnetron sputtering in this invention.

[0027] Figure 5 This is a nanoindentation hardness diagram of Ag / FeMnCrNi layered composite materials with different gradient structures according to the present invention. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings. These descriptions are intended to explain the invention and not to limit it.

[0029] A gradient structure Ag / FeMnCrNi composite material includes alternating Ag layers and FeMnCrNi layers, wherein the FeMnCrNi layers comprise 30.20 at.%, Fe-23.94 at.%, Mn-23.76 at.%, Cr-22.1 at.% Ni.

[0030] The Ag layer and FeMnCrNi layer have the same thickness in one modulation cycle, and the thickness gradient of the Ag layer and FeMnCrNi layer increases in each modulation cycle. The total thickness of the composite material is 1.4μm-1.5μm, and the change in the layer thickness gradient Δh is less than 25nm.

[0031] The Ag layer of the gradient structure Ag / FeMnCrNi layered composite material is crystalline, with columnar crystal morphology. When the thickness of the surface layer of the composite material is less than 50 nm, the internal structure of the FeMnCrNi layer is a dual-phase structure in which a small number of crystals are "embedded" in an amorphous structure. When the thickness of the surface layer of the composite material is greater than 50 nm, the internal structure of the FeMnCrNi layer is an amorphous structure.

[0032] This Ag / FeMnCrNi layered composite material is composed of multiple alternating Ag layers and FeMnCrNi alloy layers, forming a unique layered structure and a high-density heterogeneous interface. Simultaneously, utilizing the design concept of a multi-scale gradient non-uniform structure, the multi-principal element effect of the HEA (Heat-Enhanced Aluminum Alloy) is combined with the constraint effect of the gradient interlayer heterogeneous interface to construct a soft-hard heterogeneous structure gradient. During plastic deformation, the strain gradient generated due to the different deformation of the soft and hard components affects the overall mechanical behavior of the metal layered composite material, ultimately achieving a breakthrough in mechanical properties. The Ag / FeMnCrNi layered composite material has stable dimensions within the nanocrystalline range. This composite material possesses excellent mechanical properties, including a dense structure and good plastic deformation capacity. The interface structure and mechanical properties are enhanced as the gradient decreases. The hardness of this gradient structure Ag / FeMnCrNi layered composite material ranges from 2.92 GPa to 3.45 GPa.

[0033] A method for preparing a gradient structure Ag / FeMnCrNi composite material includes the following steps:

[0034] Step 1: Clean the silicon substrate and remove the oxide film on the surface.

[0035] First, the silicon substrate is polished, cleaned, and dried.

[0036] The silicon substrate is polished on one side, and then ultrasonically cleaned with acetone and alcohol for at least 15 minutes each. It is then dried quickly with warm air to ensure that the surface of the silicon substrate is clean, free of stains and dust, and has a roughness of less than 0.5-0.8 nm.

[0037] Secondly, the oxide film on the surface of the dried silicon substrate is removed using a hydrofluoric acid aqueous solution;

[0038] The dried silicon substrate was immersed in a hydrofluoric acid aqueous solution for at least 5 minutes and then dried to remove the oxide film on the surface of the silicon substrate. The concentration of the hydrofluoric acid aqueous solution was 35 wt.%-45 wt.%.

[0039] Step 2: In a vacuum environment, using Ar + Ion etching of the substrate.

[0040] The silicon substrate after oxide film removal is placed into the coating chamber, and the back vacuum is evacuated to 4.0 × 10⁻⁶. -4 Etching is performed below Pa, Ar + The ion etching power is 200W, and the etching time is at least 5 minutes; the Ar gas introduction time before pre-sputtering is at least 30 seconds; the pre-sputtering time is at least 8 seconds.

[0041] Step 3: On the etched substrate surface, Ag and FeMnCrNi layers are alternately deposited by DC magnetron sputtering using Ag and FeMnCrNi targets. The thickness of Ag and FeMnCrNi targets is the same within one modulation cycle. The thickness gradient of Ag and FeMnCrNi layers increases in each modulation cycle until the total thickness of the composite material reaches the preset thickness. The composite material is then cooled to room temperature in the furnace to obtain the Ag / FeMnCrNi composite material.

[0042] Both the Ag target and the FeMnCrNi target are powered by a DC power supply of 200W, with a deposition gas pressure of 0.7Pa. The silicon substrate rotation speed during magnetron sputtering co-sputtering deposition is 15r / min, and the preset thickness is 1.4-1.5μm.

[0043] The atomic ratio of the FeMnCrNi target is: 30.43 at.% Fe - 20.46 at.% Mn - 22.29 at.% Cr - 26.82 at.% Ni; the Ag target purity is not less than 99.99 wt.%.

[0044] Example 1

[0045] A method for preparing a gradient structure Ag / FeMnCrNi composite material includes the following steps:

[0046] Step 1: After single-sided polishing, the silicon substrate is ultrasonically cleaned in analytical acetone and anhydrous ethanol for 15 minutes to remove surface impurities. Then, the silicon substrate is immersed in 36wt.% hydrofluoric acid for 5 minutes to remove oxides on the substrate surface.

[0047] Step 2: Fix the substrate onto the base plate using conductive adhesive, and use the mechanical automatic arm of the magnetron sputtering machine to guide it into the magnetron sputtering vacuum coating chamber. Etch the substrate to a back vacuum of 3.8×10-4 Pa and begin etching. The etching power is 200W and the etching time is 5min.

[0048] Step 3: Using Ag and FeMnCrNi targets and combined with DC magnetron sputtering, Ag and FeMnCrNi layers of equal thickness are alternately deposited on the substrate surface. The thickness gradient change Δh between two adjacent modulation cycles is 5nm, that is, the thickness change of Ag and FeMnCrNi layers between two adjacent modulation cycles is 5nm. The deposition time of each modulation cycle increases sequentially, and the total deposition time is 7056s.

[0049] The DC power of the FeMnCrNi targets was 200W, the deposition gas pressure was 0.7Pa, the Ar gas flow rate was 50sccm, the deposition temperature was room temperature, and the substrate rotation speed was 15r / min. The Ag target power supply and the FeMnCrNi target power supply were turned on alternately to deposit the corresponding thicknesses. Table 1 shows the deposition time of Ag target and FeMnCrNi target for a single layer, and the total deposition time was 7056s.

[0050] Table 1 Deposition timeline of Example 1

[0051]

[0052] Step 4: After naturally cooling the composite material to room temperature in a high vacuum coating chamber for 2-3 hours, the composite material is removed to obtain an Ag / FeMnCrNi layered composite material with a total thickness of 1.4 μm and a layer thickness gradient of Δh = 5 nm.

[0053] The microstructure and mechanical properties of the prepared Ag / FeMnCrNi layered composite material were characterized. The interlayer interface type was found to be crystalline-amorphous, with the Ag layer exhibiting columnar crystals. As the gradient layer thickness increased, when the surface layer thickness was less than 50 nm, the FeMnCrNi layer showed a dual-phase structure with a small number of crystals "embedded" within the amorphous layer; when the surface layer thickness was greater than 50 nm, the FeMnCrNi layer exhibited an amorphous structure. The hardness was measured to be 3.46 ± 0.06 GPa under a 3000 μN nanoindentation load.

[0054] Example 2

[0055] A method for preparing a gradient structure Ag / FeMnCrNi composite material includes the following steps:

[0056] Step 1: After single-sided polishing, the silicon substrate is ultrasonically cleaned in analytical acetone and anhydrous ethanol for 15 minutes to remove surface impurities. Then, the silicon substrate is immersed in 36wt.% hydrofluoric acid for 5 minutes to remove oxides on the substrate surface.

[0057] Step 2: Fix the substrate onto the base plate using conductive adhesive, and use the mechanical automatic arm of the magnetron sputtering machine to guide it into the magnetron sputtering vacuum coating chamber. Etch the substrate to a back vacuum of 3.2×10-4 Pa and begin etching. The etching power is 200W and the etching time is 5min.

[0058] Step 3: Using Ag targets and FeMnCrNi targets combined with DC magnetron sputtering, Ag layers and FeMnCrNi layers of equal thickness are alternately deposited on the substrate surface. The thickness gradient change Δh between two adjacent modulation cycles is 10 nm, and the deposition time of each modulation cycle increases sequentially. The total deposition time is 7626 s.

[0059] The DC power of the FeMnCrNi targets was 200W, the deposition gas pressure was 0.7Pa, the Ar gas flow rate was 50sccm, the deposition temperature was room temperature, and the substrate rotation speed was 15r / min. The Ag target power supply and the FeMnCrNi target power supply were turned on alternately to deposit the corresponding thicknesses. Table 2 shows the deposition time of Ag target and FeMnCrNi target for a single layer, and the total deposition time was 7626s.

[0060] Table 2 Deposition schedule of Example 2

[0061]

[0062] Step 4: After naturally cooling the composite material to room temperature in a high vacuum coating chamber for 2-3 hours, the composite material is removed to obtain an Ag / FeMnCrNi layered composite material with a total thickness of 1.4 μm and a layer thickness gradient increase of Δh = 10 nm.

[0063] The gradient-structure Ag / FeMnCrNi layered composite material prepared in this embodiment was characterized by its microstructure and mechanical properties. The interlayer interface type was found to be crystalline-amorphous, with the Ag layer exhibiting columnar crystals. As the gradient layer thickness increased, when the surface layer thickness was less than 50 nm, the FeMnCrNi layer showed a dual-phase structure with a small number of crystals "embedded" within the amorphous layer; when the surface layer thickness was greater than 50 nm, the FeMnCrNi layer exhibited an amorphous structure. Under a 3000 μN load, nanoindentation measured its hardness to be 2.92 ± 0.03 GPa.

[0064] Example 3

[0065] The difference between this embodiment and embodiment 2 lies in the thickness gradient change in step 3 and the deposition time for each modulation cycle; the rest of the methods are the same.

[0066] A method for preparing a gradient structure Ag / FeMnCrNi composite material includes the following steps:

[0067] Step 1: Clean the silicon substrate and remove the oxide film on the surface.

[0068] Step 2: In a vacuum environment, using Ar + Ion etching of the substrate.

[0069] Step 3: Using Ag targets and FeMnCrNi targets combined with DC magnetron sputtering, Ag layers and FeMnCrNi layers of equal thickness are alternately deposited on the substrate surface. The thickness gradient change Δh between two adjacent modulation cycles is 20 nm, and the deposition time of each modulation cycle increases sequentially. The total deposition time is 7626 s.

[0070] The DC power of the FeMnCrNi targets was 200W, the deposition gas pressure was 0.7Pa, the Ar gas flow rate was 50sccm, the deposition temperature was room temperature, and the substrate rotation speed was 15r / min. The Ag target power supply and the FeMnCrNi target power supply were turned on alternately to deposit the corresponding thicknesses. Table 3 shows the deposition time of Ag target and FeMnCrNi target for a single layer, and the total deposition time was 7626s.

[0071] Table 3 Deposition timeline of Example 3

[0072]

[0073] Step 4: After naturally cooling the composite material to room temperature in a high vacuum coating chamber for 2-3 hours, the composite material is removed to obtain an Ag / FeMnCrNi layered composite material with a total thickness of 1.4 μm and a layer thickness gradient increase of Δh = 20 nm.

[0074] The gradient structure Ag / FeMnCrNi layered composite material prepared in this embodiment was characterized by microstructure and tested for mechanical properties. The interlayer interface type is crystalline-amorphous interface, and the Ag layer is columnar crystal. As the gradient layer thickness increases, when the thickness of the surface layer of the composite material is less than 50 nm, the internal structure of the FeMnCrNi layer is a two-phase structure with a small number of crystals "embedded" in amorphous material. When the thickness of the surface layer of the composite material is greater than 50 nm, the internal structure of the FeMnCrNi layer is amorphous. The hardness measured by nanoindentation under a load of 3000 μN is 2.91 ± 0.04 GPa.

[0075] Example 4

[0076] A method for preparing a gradient structure Ag / FeMnCrNi composite material includes the following steps:

[0077] Step 1: Clean the silicon substrate and remove the oxide film on the surface.

[0078] Step 2: In a vacuum environment, using Ar + Ion etching of the substrate.

[0079] Step 3: Using Ag targets and FeMnCrNi targets combined with DC magnetron sputtering, Ag layers and FeMnCrNi layers of equal thickness are alternately deposited on the substrate surface. The thickness gradient change Δh between two adjacent modulation cycles is 25 nm, and the deposition time of each modulation cycle increases sequentially, with a total deposition time of 7626 s.

[0080] The DC power of the FeMnCrNi targets was 200W, the deposition gas pressure was 0.7Pa, the Ar gas flow rate was 50sccm, the deposition temperature was room temperature, and the substrate rotation speed was 15r / min. The Ag target power supply and the FeMnCrNi target power supply were turned on alternately to deposit the corresponding thicknesses for time. Table 4 shows the deposition time of Ag target and FeMnCrNi target for a single layer, and the total deposition time was 7025s.

[0081] Table 4 Deposition timeline of Example 4

[0082]

[0083] Step 4: After naturally cooling the composite material to room temperature in a high vacuum coating chamber for 2-3 hours, the composite material is removed to obtain an Ag / FeMnCrNi layered composite material with a total thickness of 1.4 μm and a layer thickness gradient increase of Δh = 25 nm.

[0084] The gradient structure Ag / FeMnCrNi layered composite material prepared in this embodiment was characterized by microstructure and tested for mechanical properties. The interlayer interface type is crystalline-amorphous interface, and the Ag layer is columnar crystal. As the gradient layer thickness increases, when the thickness of the composite surface layer is less than 50 nm, the internal structure of the FeMnCrNi layer is a two-phase structure with a small number of crystals "embedded" in amorphous material. When the thickness of the composite surface layer is greater than 50 nm, the internal structure of the FeMnCrNi layer is amorphous. The hardness was measured to be 3.0 ± 0.05 GPa under a nanoindentation load of 3000 μN.

[0085] Comparative Example

[0086] The difference between this comparative example and Examples 1-4 is that the thickness gradient change in step 3 is 0 and the deposition time for each modulation cycle is the same; the rest of the methods are the same.

[0087] A method for preparing Ag / FeMnCrNi composite material with equal layer thickness includes the following steps:

[0088] Step 1: Clean the silicon substrate and remove the oxide film on the surface.

[0089] Step 2: In a vacuum environment, using Ar + Ion etching of the substrate.

[0090] Step 3: Using Ag targets and FeMnCrNi targets combined with DC magnetron sputtering, Ag layers and FeMnCrNi layers with a thickness of 25 nm are alternately deposited on the substrate surface, with the same thickness in each modulation period.

[0091] The DC power of the FeMnCrNi target was 200W, the deposition gas pressure was 0.7Pa, the Ar gas flow rate was 50sccm, the deposition temperature was room temperature, and the substrate rotation speed was 15r / min. The Ag target power supply and the FeMnCrNi target power supply were turned on alternately to deposit the corresponding thicknesses. The deposition time of the Ag target and the FeMnCrNi target in one modulation cycle was 48s and 203s, respectively. After 28 cycles, the total deposition time was 7028s.

[0092] Step 4: After naturally cooling the composite material to room temperature in a high-vacuum coating chamber for 2 hours, remove it to obtain a total thickness of 1.4 μm and a FeMnCrNi layer thickness h. HEA =25nm, Ag layer thickness h Ag Ag / FeMnCrNi layered composite material with a diameter of 25 nm.

[0093] The microstructure and mechanical properties of the Ag / FeMnCrNi composite material with equal layer thickness in the comparative example were characterized. When the thickness of the surface layer of the composite material was less than 50 nm, the internal structure of the FeMnCrNi layer was a two-phase structure with a small number of crystals "embedded" in the amorphous layer. When the thickness of the surface layer of the composite material was greater than 50 nm, the internal structure of the FeMnCrNi layer was an amorphous structure. The hardness was measured to be 3.11 ± 0.03 GPa under a nanoindentation load of 3000 μN.

[0094] like Figure 1 The diagram shows the structural diagrams of the Ag / FeMnCrNi layered composite materials in Examples 1-4 and the comparative example. Figure 2 -to Figure 4 The image shows the XRD pattern, typical TEM image, and nanoindentation hardness diagram of the Ag / FeMnCrNi layered composite material prepared under a DC power supply of 200W and a gas pressure of 0.7Pa. The Ag / FeMnCrNi gradient structure metal composite material was prepared by alternating deposition using magnetron sputtering. This precisely controlled the thickness gradient of the functional units, avoiding the severe plastic deformation introduced on the surface by traditional gradient structure preparation techniques (rolling / surface shot peening). The result was a uniformly structured and densely packed gradient structure layered composite material. This material holds promise for further improving strength by combining the performance advantages of the functional units and breaking through the performance limitations of traditional metal multilayer films through gradient size control.

[0095] This invention discloses a method for preparing a gradient-structured Ag / FeMnCrNi layered composite material. The method involves depositing the gradient-structured Ag / FeMnCrNi layered composite material on a clean silicon substrate using alternating DC magnetron sputtering. Ar gas is then ionized to generate Ar. + Ions accelerate and bombard the cathode target (Ag / FeMnCrNi) atoms and secondary electrons, which are then sputtered out. The target atoms move towards the anode and deposit on the anode substrate. The secondary electrons move in an arc within an orthogonal electromagnetic field, significantly enhancing collisions with Ar molecules and increasing the probability of Ar ionization. This invention features a fast deposition rate, high ionization rate, low operating temperature, and uniform elemental distribution, minimizing target element agglomeration and backsputtering. Finally, the material is naturally cooled to room temperature in a high-vacuum coating chamber to prevent the detachment and breakage of the nanolayered material due to internal stress and differences in film-substrate thermal expansion coefficients, and to prevent oxidation upon contact with air at high temperatures.

[0096] This invention provides a gradient-structured Ag / FeMnCrNi layered composite material with dimensional stability within the nanocrystalline range. The Ag / FeMnCrNi layered composite material exhibits a dense structure and excellent mechanical properties, including good plastic deformation capability. The interface structure and mechanical properties vary with the gradient: the Ag layer in this gradient-structured Ag / FeMnCrNi layered composite material is a crystalline layer; within the thinnest layer of the gradient structure, the FeMnCrNi layer has a two-phase structure of crystals "embedded" in amorphous material; within the thickest layer, the FeMnCrNi layer has an amorphous structure. The layers are uniformly dense, resulting in excellent mechanical properties.

[0097] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A gradient-structured Ag / FeMnCrNi composite material, characterized in that, The system comprises alternating Ag and FeMnCrNi layers. The Ag and FeMnCrNi layers have the same thickness in one modulation cycle, and the thickness gradient of the Ag and FeMnCrNi layers increases in each modulation cycle. The amount of change in the thickness gradient is... h is less than or equal to 25 nm, and the thickness of the Ag layer and FeMnCrNi layer in the first period is 25 nm. The FeMnCrNi layer comprises 30.20 at.% Fe, 23.94 at.% Mn, 23.76 at.% Cr, and 22.1 at.% Ni. The Ag layer of the gradient structure Ag / FeMnCrNi composite material grows in a columnar crystal structure; When the thickness of the FeMnCrNi layer on the surface of the composite material is less than 50 nm, the internal structure of the FeMnCrNi layer is a two-phase structure in which a small amount of FCC crystals are "embedded" in amorphous material. When the thickness of the FeMnCrNi layer on the surface of the composite material is greater than 50 nm, the internal structure of the FeMnCrNi layer is an amorphous structure.

2. The gradient structure Ag / FeMnCrNi composite material according to claim 1, characterized in that, The Ag / FeMnCrNi composite material has a thickness of 1.4μm-1.5μm and a hardness of 2.92 GPa-3.46 GPa.

3. A method for preparing a gradient-structure Ag / FeMnCrNi composite material according to any one of claims 1-2, characterized in that, Includes the following steps: Step 1: Clean the substrate and remove the oxide film from its surface; Step 2: Use Ag target and FeMnCrNi target to alternately deposit Ag layer and FeMnCrNi layer by DC magnetron sputtering. The thickness of Ag layer and FeMnCrNi target is the same in one modulation cycle. The thickness gradient of Ag layer and FeMnCrNi layer increases in each modulation cycle until the total thickness of composite material reaches the preset thickness. Cool to room temperature with furnace to obtain Ag / FeMnCrNi composite material.

4. The method for preparing a gradient structure Ag / FeMnCrNi composite material according to claim 3, characterized in that, The method for cleaning the substrate and removing the oxide film on the surface in step 1 is as follows: After polishing the substrate, ultrasonic cleaning is performed. After the substrate dries, acid pickling is performed to remove the oxide film on the substrate surface.

5. The method for preparing a gradient structure Ag / FeMnCrNi composite material according to claim 4, characterized in that, The amount of change in the thickness gradient in step 2 is less than or equal to 25 nm.

6. The method for preparing a gradient structure Ag / FeMnCrNi composite material according to claim 3, characterized in that, In step 2, both the Ag target and the FeMnCrNi target use a DC power supply with a power of 200W, a deposition gas pressure of 0.7 Pa, and a silicon substrate rotation speed of 15 r / min during the magnetron sputtering co-sputtering deposition process.

7. The method for preparing a gradient structure Ag / FeMnCrNi composite material according to claim 3, characterized in that, The atomic ratio of the FeMnCrNi target material is: 30.43 at.%Fe, 20.46 at.%Mn, 22.29 at.%Cr, 26.82at.%Ni.

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