High-entropy alloy microwire and preparation method thereof

Abstract

The invention provides a high-entropy alloy microwire and a preparation method thereof. The high-entropy alloy microwire comprises a high-entropy stainless steel alloy, mgO nanoparticles; and C-Si modified CrB2 nano particles are used as raw materials. Epoxy and / or silica resin; the invention discloses a polyurethane-molecular sieve microcapsule. According to the high-entropy alloy microwire prepared through the method, collaborative integration of multiple functions is achieved on the molecular level and the microscopic level, high-strength mechanical force energy and corrosion resistance are achieved, and unique technical advantages are shown. The preparation method comprises the following steps: preparing the polyurethane-molecular sieve microcapsule; mixing the polyurethane-molecular sieve microcapsules, the C-Si modified CrB2 nano-particles and epoxy or silica resin with one another to obtain prepreg; preparing an alloy material through a vacuum pressure immersion casting method; and carrying out heat treatment on the obtained alloy material.

Description

Technical Field

[0001] The present invention relates to the technical field of alloys, and particularly to a high-entropy alloy microfilament and a preparation method thereof. Background Art

[0002] Stainless steel alloys have advantages such as good electrical conductivity, thermal conductivity, high strength, high elasticity, wear resistance, corrosion resistance, and thermal stability in an oxidizing atmosphere. They are widely used in textiles and have good shielding, anti-magnetic, anti-static, and anti-radiation capabilities, as well as excellent performance.

[0003] Stainless steel alloys are widely used in industries such as textiles, aerospace, military, medicine, biochemistry, modern industry, modern civil use, and petrochemicals. Since stainless steel alloy microfilaments have a high technological content and a broad market prospect.

[0004] However, on the one hand, even the best materials are not completely immune to the effects of corrosion and oxidation. On the other hand, the mechanical properties of ordinary stainless steel alloys are not sufficient to meet the requirements for use in multiple scenarios. Based on this, how to achieve an increase in strength through the interaction between multiple phases, make up for the lack of strength, and further improve the corrosion resistance is the problem to be solved by the present invention.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-entropy alloy microfilament and a preparation method thereof. The prepared high-entropy alloy microfilament realizes the synergistic integration of multiple functions at the molecular and microscopic levels and exhibits unique technical advantages.

[0007] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0008] In the first aspect, the present invention provides a high-entropy alloy microfilament, including:

[0009] High-entropy stainless steel alloy;

[0010] MgO nanoparticles;

[0011] C-Si modified CrB2 nanoparticles;

[0012] Epoxy or silicone resin;

[0013] Polyurethane-molecular sieve microcapsules.

[0014] In an optional embodiment, the high entropy stainless steel alloy is Cr-Mo-Ni-Ti-Fe-M, wherein its basic component composition and range are: M is Sn and Al, Cr10.5-12.5wt%, Mo 1.0-4.0wt%, Ni 1.5-2.5wt%, Ti1.5-2.2wt%, Sn 0.03-0.3wt%, Al 0.1-0.3wt%, and the rest are iron and unavoidable impurities.

[0015] In an optional embodiment, by weight:

[0016] 70-90 parts of high entropy stainless steel alloy;

[0017] MgO nanoparticles 25-40 parts;

[0018] 5-15 parts of C-Si modified CrB2 nanoparticles;

[0019] Epoxy or silicone resin 2-10 parts;

[0020] 1-8 parts of polyurethane-molecular sieve microcapsules.

[0021] In an optional embodiment, the volume fraction of the MgO nanoparticles is 10-30%.

[0022] In an optional embodiment, the volume fraction of the C-Si modified CrB2 nanoparticles is 5-10%.

[0023] In an optional embodiment, the core of the polyurethane-molecular sieve microcapsule is molecular sieve particles loaded with corrosion inhibitors, and the wall material is a cross-linked and cured polyurethane network.

[0024] In an optional embodiment, the corrosion inhibitor is benzotriazole, the polyurethane network is a three-dimensional network structure formed by curing cross-linked polyurethane, and the molecular sieve particles are 4A molecular sieve particles.

[0025] In an optional embodiment, the epoxy resin is one of bisphenol A epoxy resin, novolac epoxy resin, and amino epoxy resin; the silicone resin is one of methyl silicone resin, acrylic modified silicone resin, and phenyl silicone resin.

[0026] In an optional embodiment, the C-Si modified CrB2 nanoparticles are CrB2 nanoparticles modified with silane and hydroxylated carbon black.

[0027] In an optional embodiment, the particle size of the MgO nanoparticles is 0.5-1.2 μm, and the particle size of the CrB2 nanoparticles modified by silane and hydroxylated carbon black is 50-300 nm.

[0028] Second aspect, the present invention provides a method for preparing a high-entropy alloy microfilament as described in any one of the foregoing embodiments, comprising the following steps:

[0029] Step S1, prepare polyurethane-molecular sieve microcapsules;

[0030] Step S2, mix polyurethane-molecular sieve microcapsules, C-Si modified CrB2 nanoparticles with epoxy or silicone resin prepreg;

[0031] Step S3, prepare an alloy material by vacuum pressure impregnation casting;

[0032] Step S4, perform heat treatment on the obtained alloy material.

[0033] In an alternative embodiment, step S2 includes the following steps:

[0034] First, stir and mix epoxy or silicone resin with a curing agent at 60 ± 5 °C;

[0035] Second, add polyurethane-molecular sieve microcapsules, C-Si modified CrB2 nanoparticles, and stir gently at 40 ± 2 °C;

[0036] Then, coat the mixture on a glass fiber cloth;

[0037] Finally, vacuum dry at room temperature for 12 hours.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] The beneficial effects of this application are mainly reflected in the following aspects:

[0040] The present invention provides a high-entropy alloy microfilament, including a high-entropy stainless steel alloy, MgO nanoparticles, and C-Si modified CrB2 nanoparticles. The MgO nanoparticles have good mechanical properties themselves. The C-Si modified CrB2 nanoparticles form a flexible connection bridge between the high-entropy stainless steel alloy and the MgO nanoparticles. During the service process of the composite material, under the action of load and stress, the C-Si modified CrB2 nanoparticles stacked outside the MgO nanoparticles can hinder crack propagation, and can play a role in synergistically strengthening and toughening the stainless steel alloy, improving the strength and toughness of the composite material, so that the stainless steel alloy maintains the lightweight and low-expansion characteristics of the existing MgO nanoparticle-reinforced aluminum matrix composite material while having more excellent mechanical properties.

[0041] A uniform MgAl2O4 microzone reaction layer can be formed between the high-entropy stainless steel alloy and the MgO nanoparticles, thereby improving the wettability and bonding strength between the MgO nanoparticles and the stainless steel matrix. Preferably, the aluminum alloy is an Al-Sn-M alloy.

[0042] After multiple damage-repair cycles, the material can still maintain a high repair efficiency. This shows that the self-healing system of the present invention has persistence and repeatability, which is of great significance for extending the service life of the material.

[0043] In summary, the present application proposes a high-entropy alloy microfilament and its preparation method. By setting MgO nanoparticles, C-Si modified CrB2 nanoparticles, epoxy and / or silicone resin, polyurethane-molecular sieve microcapsules, this multifunctional integration not only overcomes the limitations of a single material system, but also realizes an overall improvement in performance through synergistic effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0045] Figure 1 Schematic diagrams of the mechanical properties of each example and comparative example;

[0046] Figure 2 Schematic diagrams of the cyclic damage-repair tests of the examples and comparative examples;

[0047] Figure 3 Schematic diagrams of the corrosion resistance tests of the examples and comparative examples. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] The following will describe the implementation schemes of the present invention in detail with reference to the examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. The reagents or instruments not specified by the manufacturer can all be obtained through commercial purchases and are conventional products.

[0049] The embodiments of the present application provide a high-entropy alloy microfilament, including: high-entropy stainless steel alloy; MgO nanoparticles; C-Si modified CrB2 nanoparticles; epoxy and / or silicone resin; polyurethane-molecular sieve microcapsules.

[0050] Preferably, the base component composition and its range are as follows: the high-entropy stainless steel alloy is Cr-Mo-Ni-Ti-Fe-M, where the base component composition and its range are: where M is Sn and Al, Cr is 10.5-12.5 wt%, Mo is 1.0-4.0 wt%, Ni is 1.5-2.5 wt%, Ti is 1.5-2.2 wt%, Sn is 0.03-0.3 wt%, Al is 0.1-0.3 wt%, and the rest is iron and inevitable impurities.

[0051] More specifically, the high-entropy stainless steel alloy includes Cr-Mo-Ni-Ti-Fe-Al-Sn.

[0052] The high-entropy stainless steel alloy can further add at least one of the microalloying accessory elements Hf, Nb, V, Sc, Er, Yb. The addition amount of at least one of the microalloying accessory elements Hf, Nb, V, Sc, Er, Yb satisfies 0.06 ≤ (Zr + Hf + Nb + V + Sc + Er + Yb) wt% ≤ 0.5 wt%.

[0053] The iron raw material is pure iron, and other alloying elements are added in the form of iron-based master alloys.

[0054] Chromium is beneficial to the corrosion resistance provided by the alloy of the present invention.

[0055] Molybdenum is beneficial to the strength provided by the alloy by participating in the precipitation of strengthening phases such as the R phase during the age hardening process of the alloy.

[0056] Titanium and nickel combine to form the primary strengthening phase Ni3Ti during the age hardening heat treatment process.

[0057] A small amount of aluminum is considered to increase the Ms temperature of the alloy, which helps to ensure complete transformation into the martensite phase.

[0058] Furthermore, the mass percentage of the Sn element is 0.03-0.3 wt%.

[0059] For example, it can be 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.15 wt%, 0.20 wt%, 0.25 wt%, 0.3 wt%, etc.

[0060] The beneficial effects of the contents of the Sn and Al elements will be described next.

[0061] By weight:

[0062] 70-90 parts of high-entropy stainless steel alloy;

[0063] 25-40 parts of MgO nanoparticles;

[0064] 5 - 15 parts of C-Si modified CrB2 nanoparticles;

[0065] 2 - 10 parts of epoxy and / or silicone resin;

[0066] The epoxy resin can be one of bisphenol A epoxy resin, phenolic epoxy resin, and amino epoxy resin. More preferably, the epoxy resin is bisphenol A epoxy resin.

[0067] The silicone resin can be one of methyl silicone resin, acrylic modified silicone resin, and phenyl silicone resin. More preferably, the silicone resin is phenyl silicone resin.

[0068] 1 - 8 parts of polyurethane - molecular sieve microcapsules;

[0069] The core of the polyurethane - molecular sieve microcapsule is molecular sieve particles loaded with a corrosion inhibitor, and the wall material is a cross - linked and cured polyurethane network.

[0070] The corrosion inhibitor is benzotriazole;

[0071] The molecular sieve particles are 4A molecular sieve particles;

[0072] Polyurethane network: The polyurethane is cross - linked polyurethane. Through neutralization with triethylamine and cross - linking reaction with ethylenediamine, the polyurethane prepolymer cures on the surface of the oil - phase droplets to form a three - dimensional network structure with a high cross - link density, constituting the outer shell of the microcapsule.

[0073] In some embodiments, the weight parts of each component include:

[0074] 70 - 90 parts of high - entropy stainless steel alloy; for example, the weight parts of the high - entropy stainless steel alloy can be 70, 75, 80, 85, 90, etc.

[0075] 25 - 40 parts of MgO nanoparticles; for example, the weight parts of the MgO nanoparticles can be 25, 30, 34, 37, 40, etc.

[0076] 5 - 15 parts of C-Si modified CrB2 nanoparticles; for example, the weight parts of the C-Si modified CrB2 nanoparticles can be 5, 7, 10, 15, etc.

[0077] 2 - 10 parts of epoxy and / or silicone resin; the weight parts of the epoxy and / or silicone resin can be 2, 4, 5, 7, 8, 10, etc.

[0078] 1 - 8 parts of polyurethane - molecular sieve microcapsules; the weight parts of the polyurethane - molecular sieve microcapsules can be 1, 2, 4, 6, 8, etc.

[0079] Furthermore, the volume fraction of the MgO nanoparticles is 10 - 30%.

[0080] For example, it can be 10%, 12%, 15%, 17%, 20%, 24%, 26%, 28%, 30%, etc.

[0081] Furthermore, the volume fraction of the C-Si modified CrB2 nanoparticles is 5-10%.

[0082] For example, it can be 10%, 12%, 15%, 17%, 20%, 24%, 26%, 28%, 30%, etc.

[0083] Furthermore, the C-Si modified CrB2 nanoparticles are CrB2 nanoparticles modified by silane and hydroxylated carbon black.

[0084] Furthermore, the particle size of the MgO nanoparticles is 0.5-1.2 μm; it can be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, etc. The particle size of the CrB2 nanoparticles modified by silane and hydroxylated carbon black (C-Si modified CrB2 nanoparticles) is 50 nm-300 nm. For example, it can be 50 nm, 70 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, etc.

[0085] The present invention also provides a method for preparing a high-entropy alloy microfilament, comprising the following steps:

[0086] Step S1, preparing polyurethane-molecular sieve microcapsules;

[0087] Step S2, mixing the polyurethane-molecular sieve microcapsules, C-Si modified CrB2 nanoparticles with epoxy and / or silicone resin prepreg;

[0088] Step S3, preparing an alloy material by vacuum pressure impregnation casting;

[0089] Step S4, heat-treating the obtained alloy material.

[0090] Step S1, the specific experimental steps of the polyurethane-molecular sieve microcapsules are as follows: adding the molecular sieve loaded with the corrosion inhibitor into the acetone solution of the polyurethane prepolymer, ultrasonically dispersing, adding an appropriate amount of Tween 80 as an emulsifier, and then slowly dropping the mixture into deionized water, stirring to form a water-in-oil emulsion; adding triethylamine (TEA) to the emulsion for a neutralization reaction, stirring, slowly dropping ethylenediamine as a crosslinking agent, and stirring and reacting at room temperature to further crosslink and cure the polyurethane prepolymer to form microcapsules. Among them, the preparation method of the molecular sieve loaded with the corrosion inhibitor is: adding 4A molecular sieve into the acetone solution of benzotriazole (BTA), stirring for 24 h, filtering under reduced pressure, separating, washing and drying to obtain the molecular sieve loaded with the corrosion inhibitor.

[0091] The preparation method of the polyurethane prepolymer is as follows: Isophorone diisocyanate (IPDI) and an appropriate amount of dibutyltin dilaurate (DBTDL) catalyst are added to a three-necked flask, heated to 80 °C and reacted for 2 hours, then dimethylolpropionic acid (DMPA) is added, and the reaction continues for 3 hours to obtain a polyurethane prepolymer containing carboxyl groups. An appropriate amount of acetone is added to the prepolymer to reduce the viscosity of the system, and then it is cooled to 40 °C.

[0092] The preparation method of silane- and hydroxylated carbon black-modified CrB2 nanoparticles includes:

[0093] 1) Dispersing the CrB2 nanoparticles into ethylene glycol monobutyl ether, stirring, heating, adding silane, continuing to stir, then dropwise adding deionized water during stirring, and adjusting the pH to 7-8 with triethanolamine, reacting, and finally filtering the product, washing it 2-3 times with absolute ethanol and then drying to obtain surface-modified CrB2 nanoparticles;

[0094] 2) Mixing hydroxylated carbon black in ethylene glycol monobutyl ether and stirring. Adding KH560 and deionized water, adjusting the pH of the solution to 7-8 and then reacting. Adding the surface-modified CrB2 nanoparticles and continuing to react. Then filtering the product, washing it with absolute ethanol, and drying to obtain C-Si modified CrB2 nanoparticles (silane- and hydroxylated carbon black-modified CrB2 nanoparticles).

[0095] The specific experimental steps for mixing the polyurethane-molecular sieve microcapsules, C-Si modified CrB2 nanoparticles with epoxy and / or silicone resin prepregs are as follows: First, mix epoxy and / or silicone resin with a curing agent at 60 ± 5 °C with stirring; second, add the polyurethane-molecular sieve microcapsules, C-Si modified CrB2 nanoparticles, and stir gently at 40 ± 2 °C; then, coat the mixture on a glass fiber cloth; finally, vacuum dry at room temperature for 12 hours.

[0096] The specific experimental steps for preparing the alloy material by the vacuum pressure infiltration method in step S3 are: Alternately lay epoxy and / or silicone resin prepregs and MgO nanoparticles in a mold, then place the mold in a vacuum pressure infiltration device, evacuate to -0.2 MPa; again, inject molten high-entropy stainless steel alloy while applying a pressure of 20-30 MPa; finally, maintain the pressure and cool to room temperature at a rate of 10 ± 2 °C / min.

[0097] The preparation method of the high-entropy stainless steel alloy therein is as follows: According to the mass percentages of the elements in the high-entropy stainless steel alloy, raw materials are prepared in accordance with the alloy composition and the burning loss amount, and are reserved after pretreatment; the iron raw material is heated to melting, and then other raw materials are added to the molten iron liquid, stirred for 10 to 20 minutes, and then an inert gas is introduced into the molten metal liquid for degassing for 5 to 20 minutes to obtain an alloy melt.

[0098] The specific experimental steps for heat-treating the obtained alloy material in step S4 are as follows: First, the composite material is heated to 530 ± 5 °C at a rate of 5 °C / min and held for 1 hour; second, it is water-quenched to room temperature; then, it is aged at 190 ± 5 °C for 4 hours; finally, it is air-cooled to room temperature.

[0099] The iron raw material is pure iron, and the other metal materials are intermediate alloys of metal and iron.

[0100] Example 1

[0101] The present invention provides a high-entropy alloy microfilament, which comprises 70 parts of Cr-Mo-Ni-Ti-Fe-Al-Sn alloy, 25 parts of MgO nanoparticles with a particle size of 0.5 μm, 5 parts of C-Si modified CrB2 nanoparticles with a particle size of 100 nm, 2 parts of bisphenol A epoxy resin, and 1 part of polyurethane-molecular sieve microcapsule by weight fraction.

[0102] In the Cr-Mo-Ni-Ti-Fe-Al-Sn alloy, Cr is 10.5 wt%, Mo is 1.0 wt%, Ni is 1.5 wt%, Ti is 1.5 wt%, Sn is 0.03 wt%, Al is 0.1 wt%, and the balance is iron, incidental elements and unavoidable impurities.

[0103] The volume fraction of the MgO nanoparticles is 10%.

[0104] Experimental method:

[0105] Step S1: First, prepare polyurethane-molecular sieve microcapsules: Add 10 g of 4A molecular sieve loaded with a corrosion inhibitor (benzotriazole) to 100 g of an acetone solution of polyurethane prepolymer, ultrasonically disperse for 30 minutes, add 2 g of Tween 80 as an emulsifier, and then slowly drop the mixture into deionized water and stir at a speed of 1000 r / min to form a water-in-oil emulsion; add 2 g of triethylamine (TEA) to the emulsion for neutralization reaction, stir, slowly drop 2 g of ethylenediamine as a cross-linking agent, and stir and react at room temperature for 2 h to further cross-link and cure the polyurethane prepolymer to form microcapsules; remove acetone by the method of vacuum distillation, and then collect the microcapsules by centrifugation, wash 3 times with deionized water, and vacuum dry at 40 °C for 24 h to obtain polyurethane-molecular sieve microcapsules.

[0106] Preparation method of molecular sieve loaded with corrosion inhibitor: 25 g of 4A molecular sieve was added to 100 ml of acetone solution of benzotriazole (BTA, 0.1 mol / L), stirred for 24 h, separated by vacuum filtration, washed, and dried at 60 °C for 12 h to obtain the molecular sieve loaded with corrosion inhibitor.

[0107] Preparation method of polyurethane prepolymer: 50 g of polyether polyol (PPG), 50 g of isophorone diisocyanate (IPDI) and 5 g of dibutyltin dilaurate (DBTDL) catalyst were added to a 500 ml three-necked flask, heated to 80 °C and reacted for 2 h. Then 50 g of dimethylolpropionic acid (DMPA) was added and the reaction continued for 3 h to obtain a carboxyl-containing polyurethane prepolymer.

[0108] Experimental method for preparing C-Si modified CrB2 nanoparticles: 10 g of CrB2 nanoparticles were dispersed in 50 ml of ethylene glycol monobutyl ether, stirred at a rate of 800 r / min, heated to 40 °C, 10 g of silane was added, and stirring continued for 20 min. Then 10 g of deionized water was added dropwise during stirring, and the pH was adjusted to 7-8 with triethanolamine, and the reaction was carried out for 8 h. Finally, the product was filtered, washed 2-3 times with absolute ethanol and dried at 30 °C for 10 h to obtain surface-modified CrB2 nanoparticles; 1 g of hydroxylated carbon black was mixed in 50 ml of ethylene glycol monobutyl ether and stirred. 15 g of KH560 and 15 g of deionized water were added, the pH of the solution was adjusted to 7-8 and the reaction was carried out for 3 h. Then 10 g of surface-modified CrB2 nanoparticles were added and the reaction continued. Then the product was filtered, washed with absolute ethanol and dried to obtain C-Si modified CrB2 nanoparticles.

[0109] Step S2: The specific experimental steps of the polyurethane-molecular sieve microcapsule, C-Si modified CrB2 nanoparticles and epoxy resin prepreg are as follows: 100 g of bisphenol A epoxy resin, 10 g of C-Si modified CrB2 nanoparticles, and 10 g of benzoyl peroxide (curing agent) were added to a 250 mL beaker and stirred at 58 °C for 30 minutes until completely dissolved. Then 15 g of the prepared polyurethane-molecular sieve microcapsule was added and gently stirred at 38 °C for 10 minutes to avoid damaging the microcapsules. The mixture was coated on a glass fiber cloth to make a prepreg. Finally, it was vacuum dried at room temperature for 12 hours.

[0110] Step S3: Preparation of alloy material by vacuum pressure impregnation method: A layer of prepreg was evenly laid at the bottom of the mold, and MgO nanoparticles were evenly distributed on the prepreg. The mold was placed in a vacuum pressure impregnation device, evacuated to -0.1 MPa and maintained for 10 minutes. The Cr-Mo-Ni-Ti-Fe-Al-Sn alloy melt was injected while applying a pressure of 20 MPa. The pressure was maintained and cooled to room temperature at a rate of 8 °C / min.

[0111] Among them, the Cr-Mo-Ni-Ti-Fe-Al-Sn alloy pre-treats the materials according to the above mass ratio, heats to 1050 °C to melt the iron, adds the Cr raw material (Cr-Fe alloy) and other raw materials (Mo-Fe alloy, Ni-Fe alloy, Al-Fe alloy, Sn-Fe alloy) into the molten iron liquid, stirs for 15 min, and then passes nitrogen into the molten metal liquid for degassing for 20 min to obtain the Cr-Mo-Ni-Ti-Fe-Al-Sn alloy melt.

[0112] Step S4: Heat-treat the obtained alloy material: Heat the alloy material to 525 °C at a rate of 5 °C / min and hold for 1 hour. Then water-quench to room temperature, perform aging treatment at 185 °C for 4 hours, and finally air-cool to room temperature.

[0113] Example 2

[0114] The present invention provides a high-entropy alloy microfilament, which is different from Example 1 in that it includes 80 parts by weight of Cr-Mo-Ni-Ti-Fe-Al-Sn alloy, 30 parts by weight of MgO nanoparticles, 10 parts by weight of C-Si modified CrB2 nanoparticles, 6 parts by weight of epoxy resin, and 4 parts by weight of polyurethane-molecular sieve microcapsules.

[0115] Example 3

[0116] The present invention provides a high-entropy alloy microfilament, which is different from Example 1 in that it includes 90 parts by weight of Cr-Mo-Ni-Ti-Fe-Al-Sn alloy, 40 parts by weight of MgO nanoparticles, 15 parts by weight of C-Si modified CrB2 nanoparticles, 10 parts by weight of epoxy resin, and 8 parts by weight of polyurethane-molecular sieve microcapsules.

[0117] Example 4

[0118] The present invention provides a high-entropy alloy microfilament, which is different from Example 1 in that bisphenol A epoxy resin is replaced by phenyl silicone resin.

[0119] Example 5

[0120] The present invention provides a high-entropy alloy microfilament, which is different from Example 1 in that the particle size of the MgO nanoparticles is 1.2 , and the particle size of the C-Si modified CrB2 nanoparticles is 300 nm.

[0121] Example 6

[0122] The present invention provides a high-entropy alloy microfilament, which is different from that of Example 1 in that the composition range of the high-entropy stainless steel alloy as Cr-Mo-Ni-Ti-Fe-Al-Sn alloy is replaced by Cr 12.5 wt%, Mo 4.0 wt%, Ni 2.5 wt%, Ti 2.2 wt%, Sn 0.3 wt%, and Al 0.3 wt%.

[0123] Comparative Example 1

[0124] The high-entropy alloy microfilament prepared in this example, compared with Example 1, is different in that no MgO nanoparticles are provided.

[0125] Experimental method: Compared with Example 1, the difference is in step S3. The alloy material is prepared by the vacuum pressure impregnation casting method: A layer of mixed prepreg is evenly laid at the bottom of the mold. The mold is placed in a vacuum pressure impregnation casting device, evacuated to -0.1 MPa, and maintained for 10 minutes. The Cr-Mo-Ni-Ti-Fe-Al-Sn alloy melt is injected while applying a pressure of 20 MPa. The pressure is maintained and cooled to room temperature at a rate of 8 °C / min.

[0126] Comparative Example 2

[0127] The high-entropy alloy microfilament prepared in this example, compared with Example 1, is different in that no C-Si modified CrB2 nanoparticles are provided.

[0128] Experimental method: Compared with Example 1, the difference is in step S2. The specific experimental steps of the polyurethane-molecular sieve microcapsule and epoxy resin prepreg are as follows: Add 100 g of bisphenol A epoxy resin and 10 g of benzoyl peroxide (curing agent) to a 250 mL beaker, and stir at 58 °C for 30 minutes until completely dissolved. Then add 15 g of the prepared polyurethane-molecular sieve microcapsules, and stir gently at 38 °C for 10 minutes to avoid damaging the microcapsules. Coat the mixture on the glass fiber cloth to make a prepreg. Finally, vacuum dry at room temperature for 12 hours.

[0129] Comparative Example 3

[0130] The high-entropy alloy microfilament prepared in this example, compared with Example 1, is different in that no MgO nanoparticles and C-Si modified CrB2 nanoparticles are provided.

[0131] Experimental method: The difference compared with Example 1 is in step S2. The specific experimental steps for the polyurethane-molecular sieve microcapsule and epoxy resin mixed prepreg are as follows: Add 100 g of bisphenol A epoxy resin and 10 g of benzoyl peroxide (curing agent) into a 250 mL beaker, and stir at 58 °C for 30 minutes until completely dissolved. Then add 15 g of the prepared polyurethane-molecular sieve microcapsules, and stir gently at 38 °C for 10 minutes to avoid damaging the microcapsules. Coat the mixture on a glass fiber cloth to make a prepreg. Finally, vacuum dry at room temperature for 12 hours; S3. Prepare the alloy material by the vacuum pressure infiltration casting method: Uniformly lay a layer of the mixed prepreg at the bottom of the mold. Place the mold in a vacuum pressure infiltration casting device, evacuate to -0.1 MPa, and hold for 10 minutes. Inject the Cr-Mo-Ni-Ti-Fe-Al-Sn alloy melt while applying a pressure of 20 MPa. Maintain the pressure and cool to room temperature at a rate of 8 °C / min.

[0132] Comparative Example 4

[0133] In this example, the prepared high-entropy alloy microfilaments are different from those in Example 1 in that the C-Si modified CrB2 nanoparticles are replaced with CrB2 nanoparticles.

[0134] Experimental method: The difference compared with Example 1 is in step S2. The specific experimental steps for the polyurethane-molecular sieve microcapsule, CrB2 nanoparticles and epoxy resin mixed prepreg are as follows: Add 100 g of bisphenol A epoxy resin, 10 g of CrB2 nanoparticles, and 10 g of benzoyl peroxide (curing agent) into a 250 mL beaker, and stir at 58 °C for 30 minutes until completely dissolved. Then add 15 g of the prepared polyurethane-molecular sieve microcapsules, and stir gently at 38 °C for 10 minutes to avoid damaging the microcapsules. Coat the mixture on a glass fiber cloth to make a prepreg. Finally, vacuum dry at room temperature for 12 hours.

[0135] Comparative Example 5

[0136] In this example, the prepared high-entropy alloy microfilaments are different from those in Example 1 in that no epoxy resin is provided.

[0137] Experimental method: The difference compared with Example 1 is in step S2. The specific experimental steps for the polyurethane-molecular sieve microcapsule and C-Si modified CrB2 nanoparticle mixed prepreg are as follows: Add 10 g of C-Si modified CrB2 nanoparticles and 10 g of benzoyl peroxide (curing agent) into a 250 mL beaker, and stir at 58 °C for 30 minutes until completely dissolved. Then add 15 g of the prepared polyurethane-molecular sieve microcapsules, and stir gently at 38 °C for 10 minutes to avoid damaging the microcapsules. Coat the mixture on a glass fiber cloth to make a prepreg. Finally, vacuum dry at room temperature for 12 hours.

[0138] Comparative Example 6

[0139] The high-entropy alloy microfilaments prepared in this example are different from those in Example 1 in that polyurethane-molecular sieve microcapsules are not provided.

[0140] Experimental method: Compared with Example 1, step S1 is not provided. The difference is that the specific experimental steps of the C-Si modified CrB2 nanoparticles and epoxy resin prepreg in step S2 are as follows: Add 100 g of bisphenol A epoxy resin, 10 g of C-Si modified CrB2 nanoparticles, and 10 g of benzoyl peroxide (curing agent) into a 250 mL beaker, and stir at 58 °C for 30 minutes until completely dissolved. Coat the mixture on the glass fiber cloth to make a prepreg. Finally, dry it in vacuum at room temperature for 12 hours.

[0141] Comparative Example 7

[0142] The high-entropy alloy microfilaments prepared in this example are different from those in Example 1 in that the Cr-Mo-Ni-Ti-Fe-Al-Sn alloy is replaced by the Cr-Mo-Ni-Ti-Fe alloy.

[0143] Experimental method: Compared with Example 1, the difference is in step S3, preparing the alloy material by the vacuum pressure infiltration casting method: evenly lay a layer of prepreg at the bottom of the mold, and evenly distribute MgO nanoparticles on the prepreg. Place the mold in a vacuum pressure infiltration casting device, evacuate to -0.1 MPa, and hold for 10 minutes. Inject the Cr-Mo-Ni-Ti-Fe alloy melt, and apply a pressure of 20 MPa at the same time. Keep the pressure and cool to room temperature at a rate of 8 °C / min.

[0144] Among them, the Cr-Mo-Ni-Ti-Fe alloy pretreats the materials according to the above mass ratio, heats to 1050 °C to melt the iron alloy, adds other raw materials (Cr-Fe alloy, Mo-Fe alloy, Ni-Fe alloy, Ti-Fe alloy) to the molten iron liquid, stirs for 15 min, and then passes nitrogen into the molten metal liquid for degassing for 20 min to obtain the Cr-Mo-Ni-Ti-Fe alloy melt.

[0145] Comparative Example 8

[0146] The high-entropy alloy microfilaments prepared in this example are different from those in Example 1 in that the proportion of Sn in the Cr-Mo-Ni-Ti-Fe-Al-Sn alloy is 0.01% wt and the proportion of Al is 0.05% wt.

[0147] Experimental method: Compared with Example 1, the experimental steps remain unchanged, only the proportion of Sn is changed.

[0148] Comparative Example 9

[0149] In this example, the high-entropy alloy microfilaments prepared are different from those in Example 1 in that the volume fraction of MgO nanoparticles is 5%.

[0150] Experimental method: Compared with Example 1, the experimental steps remain unchanged, only the volume fraction of MgO nanoparticles is changed.

[0151] Comparative Example 10

[0152] In this example, the high-entropy alloy microfilaments prepared are different from those in Example 1 in that the particle size of the MgO nanoparticles is 300 nm, and the particle size of the C-Si modified CrB2 nanoparticles is 0.5 μm.

[0153] Experimental method: Compared with Example 1, the experimental steps remain unchanged.

[0154] Comparative Example 11

[0155] In this example, the high-entropy alloy microfilaments prepared are different from those in Example 1 in that the particle size of the MgO nanoparticles is 5 μm, and the particle size of the C-Si modified CrB2 nanoparticles is 5 μm.

[0156] Experimental method: Compared with Example 1, the experimental steps remain unchanged.

[0157] Experimental results and analysis:

[0158] For the above examples and comparative examples, the following tests were carried out:

[0159] Horizontal comparison test:

[0160] Test method: Basic mechanical property test.

[0161] (1) Test experiment 1 - Basic mechanical property test:

[0162] The high-entropy alloy microfilaments prepared in the examples and comparative examples were tested for tensile strength, yield strength and fracture toughness. These tests were carried out using standard material mechanics test methods and a universal material testing machine. The test conditions were room temperature (25 ± 2 °C), relative humidity 50 ± 5%, and the tensile rate was 2 mm / min.

[0163] (2) Test experiment 2 - Cyclic damage-repair test:

[0164] The high-entropy alloy microfilaments prepared in the examples and comparative examples were subjected to cyclic damage-repair tests: First, a crack with a length of 10 mm and a width of 0.5 mm was prefabricated at the center of the specimen. Then, in the present invention, the specimen was placed in a thermostatic and humidistatic chamber to simulate different environmental conditions. Three temperature points were selected in the present invention: 25 °C (room temperature), 55 °C (slight temperature increase), and 75 °C (significant temperature increase). At each temperature, 5 cycles of damage-repair processes were carried out in the present invention. Each cycle included the following steps:

[0165] 1. Apply tension to the specimen to expand the crack by 1 mm.

[0166] 2. Unload and maintain at the specified temperature for 24 hours to allow the material to self-repair.

[0167] 3. Measure the crack length and the remaining strength of the material.

[0168] (3)Test Experiment 3 - Thermomechanical Cycle Test:

[0169] The responsiveness and stability of the high-entropy alloy microfilaments prepared in the examples and comparative examples under temperature changes were tested. The test temperature range was from -20 °C to 80 °C, and the heating and cooling rate was 2 °C / min, and a total of 100 cycles were carried out.

[0170] (4)Test Experiment 4 - Corrosion Resistance Test:

[0171] The high-entropy alloy microfilaments prepared in the examples and comparative examples were immersed in 3.5% NaCl solution for 30 days, and the weight loss and surface morphology changes of the material were measured every 5 days.

[0172] (5)The coefficient of thermal expansion test of Test Experiment 5 was carried out according to the GB4339-84 standard.

[0173] Table 1. Summary of Test Results

[0174] Sample Tensile strength (MPa) Yield strength (MPa) Fracture toughness (MPa·m¹ / ²) Self-healing efficiency at 25°C (%) Self-healing efficiency at 55°C (%) Self-healing efficiency at 75°C (%) Example 1 430 272 30 82 86 93 Example 2 442 271 32 85 89 95 Example 3 435 270 34 82 86 92 Example 4 436 275 32 86 88 94 Example 5 440 273 34 88 90 96 Example 6 446 272 35 84 89 93 Comparative Example 1 394 245 23 56 76 83 Comparative Example 2 390 248 21 48 69 88 Comparative Example 3 384 242 20 44 62 76 Comparative Example 4 424 262 33 80 86 92 Comparative Example 5 431 268 27 43 65 72 Comparative Example 6 416 266 25 23 34 42 Comparative Example 7 410 255 28 80 88 92 Comparative Example 8 412 263 30 82 87 93 Comparative Example 9 423 262 24 85 90 94 Comparative Example 10 405 263 26 84 89 94 Comparative Example 11 400 265 23 81 87 92

[0175] Table 2. Summary of Test Results

[0176] Sample Strength retention rate after 100 thermal cycles (%) Weight loss after 30-day corrosion (%) Strength retention rate after corrosion (%) <![CDATA[Coefficient of expansion / 10 -6 K -1 > Example 1 91 0.7 90 14.5 Example 2 90 0.8 94 14.2 Example 3 94 0.6 91 14.7 Example 4 91 0.7 93 14.4 Example 5 92 0.9 92 14.2 Example 6 93 0.8 93 14.7 Comparative Example 1 89 0.8 90 14.5 Comparative Example 2 82 1.5 85 14.6 Comparative Example 3 75 1.3 82 14.9 Comparative Example 4 77 1.6 88 14.8 Comparative Example 5 79 1.5 86 15.3 Comparative Example 6 90 1.0 82 16.1 Comparative Example 7 88 1.7 88 14.9 Comparative Example 8 90 1.4 90 14.8 Comparative Example 9 78 1.1 90 14.3 Comparative Example 10 80 0.8 92 14.8 Comparative Example 11 82 1.2 87 14.6

[0177] Result Analysis:

[0178] (1)As can be seen from the data in Table 1, the high-entropy alloy microfilaments prepared in Examples 1-6 have excellent mechanical properties and corrosion resistance, and further have self-repairing properties.

[0179] (2) Compared with Example 1, the difference between Comparative Example 1 and Example 1 is that without MgO nanoparticles, the mechanical properties of the product are reduced. The reasons are as follows: MgO nanoparticles have good mechanical properties themselves, and a uniform MgAl2O4 micro-region reaction layer can be formed with MgO nanoparticles in the high entropy stainless steel alloy. At the same time, Al promotes the formation of Mg2Sn phase, thereby improving the wettability and bonding strength between MgO nanoparticles and the stainless steel matrix. MgO nanoparticles promote the nucleation of aluminum grains, thereby forming a crack-free fine equiaxed grain structure during the solidification process of the alloy material. Not setting MgO nanoparticles will affect the mechanical properties of the alloy product.

[0180] (3) Compared with Example 1, the difference between Comparative Example 2 and Example 1 is that: C-Si modified CrB2 nanoparticles are not set: the overall mechanical properties and corrosion resistance of the alloy product are reduced. The reasons are: on the one hand, the C-Si modified CrB2 nanoparticles have a high density and are evenly distributed in the grains and on the grain boundaries. Al-Sn-Cr phases are obviously present on the grain boundaries and on the grains. The C-Si modified CrB2 particles act as heterogeneous nucleation points, which increase the number of nucleated grains and refine the grain size. A large number of C-Si modified CrB2 particles are enriched on the grain boundaries, which will inhibit the grain growth during the solidification process of the alloy material and improve the mechanical properties of the alloy material. On the other hand, the C-Si modified CrB2 nanoparticles can greatly improve the corrosion resistance of the alloy material. This is because the surface of C-Si modified CrB2 nanoparticles is covered with a dense silicon dioxide film. Since the surface of SiO2 modified CrB2 nanoparticles is covered with a dense silicon dioxide film, the resistivity of the alloy material increases and the conductivity is significantly reduced. However, this defect can be compensated after modification with hydroxylated carbon black. Carbon black can form a conductive channel for the preferentially corroded aluminum metal, prolong the corrosion time of the metal substrate, and improve the corrosion resistance of the alloy material.

[0181] (4) The difference between Comparative Example 3 and Example 1 is that: MgO nanoparticles and C-Si modified CrB2 nanoparticles are not provided: the effect of using MgO nanoparticles and C-Si modified CrB2 nanoparticles in combination is the best, and not providing the two substances will significantly affect the mechanical properties and corrosion resistance of the alloy product. The reason is that the combination of the two has a higher heterogeneous nucleation ability and a smaller nucleation particle spacing, that is, a smaller solidified grain is formed in the organization, the higher heterogeneous nucleation ability shortens the liquid metal shrinkage channel, which is beneficial to the backfilling of the liquid metal, and the increase in grain boundary density is beneficial to the transmission and dispersion of residual stress, thereby significantly reducing local stress concentration, and the C-Si modified CrB2 nanoparticles serve as nucleation points, and the MgO nanoparticles inhibit dendrite growth.

[0182] (5)Compared with Example 1, Comparative Example 4 is different in that the C-Si modified CrB2 nanoparticles are replaced by CrB2 nanoparticles. The anti-corrosion performance decreases significantly, but the mechanical properties change little. The reason can be referred to the above reasons.

[0183] (6)Compared with Example 1, Comparative Example 5 is different in that no epoxy resin is provided. This has little effect on the mechanical properties of the alloy product, but significantly affects the anti-corrosion performance and thermal expansion of the alloy product. The reason is that the epoxy resin, as a continuous phase, wraps the high-entropy alloy material, and its network structure can restrict the free expansion of metal particles, thereby reducing the overall thermal expansion amplitude. When compounded with C-Si modified CrB2 nanoparticles and MgO nanoparticles, the epoxy resin can improve the interfacial bonding between nanoparticles and the metal, enabling the nanoparticles to more effectively inhibit thermal expansion; the high elastic modulus and adhesiveness of the epoxy resin form an interfacial layer between metal particles, which can relieve the thermal expansion difference between the aluminum alloy and nanoparticles through elastic deformation, reducing the risk of interfacial cracks.

[0184] (7)Compared with Example 1, Comparative Example 6 is different in that no polyurethane-molecular sieve microcapsules are provided. Then the repair efficiency of the material is significantly reduced. The possible reason is that the polyurethane wraps the molecular sieve core. When the material is subjected to mechanical stress or corrosion, the microcapsules rupture and release the loaded repair agent (benzotriazole). The ruptured polyurethane forms a dense film layer on the metal surface, isolating oxygen and water. Moreover, the polyurethane binds to the hydroxyl groups on the aluminum alloy surface and C-Si modified CrB2 nanoparticles through hydrogen bonds or chemical bonds, enhancing the interfacial strength between the capsules, stainless steel alloy, and nanoparticles, reducing corrosion caused by peeling; the released 4A molecular sieve particles can physically fill microcracks, reduce stress concentration, and delay crack propagation.

[0185] (8)Compared with Example 1, Comparative Example 7 is different in that the Cr-Mo-Ni-Ti-Fe-Al-Sn alloy is replaced by the Cr-Mo-Ni-Ti-Fe alloy, without tin and aluminum elements. Tin and aluminum, as heterogeneous nucleating agents, can effectively refine the grain size of the stainless steel alloy, reduce the formation of coarse grains. The fine-grained structure can significantly improve the strength, toughness, and fatigue performance of the alloy. Tin can form a dense oxide film on the alloy surface, inhibiting the oxidation and corrosion of the stainless steel alloy. Without the formation of the Al-Sn-Mg phase, the mechanical and anti-corrosion properties of the product alloy will decrease, but other properties are not greatly affected.

[0186] (9)Compared with Example 1, Comparative Example 8 is different in that the proportion of Sn in the Cr-Mo-Ni-Ti-Fe-Al-Sn alloy is 0.01%wt and the proportion of Al is 0.05%wt. The contents of tin and aluminum elements are too low to meet the requirements for improving mechanical and anti-corrosion properties.

[0187] (10)Compared with Example 1, Comparative Example 9 is different in that the volume fraction of MgO nanoparticles is 5%, and the mechanical properties of the product are decreased. The reason is that when the content of MgO nanoparticles is insufficient, a uniform MgAl2O4 micro-region reaction layer cannot be formed between the MgO nanoparticles and the high-entropy stainless steel alloy, which cannot improve the wettability and bonding strength between the MgO nanoparticles and the aluminum matrix. On the other hand, the Mg-Al-M (metal) phase cannot be formed, reducing the mechanical properties of the alloy material.

[0188] (11)Compared with Example 1, Comparative Example 10 is different in that the particle size of the MgO nanoparticles is 300 nm, and the particle size of the C-Si modified CrB2 nanoparticles is 0.5 μm; when the particle size of the C-Si modified CrB2 nanoparticles is larger than that of the MgO nanoparticles, during the service process of the alloy material under the action of load and stress, the C-Si modified CrB2 nanoparticles outside the MgO nanoparticles cannot hinder crack propagation and cannot play a role in synergistically strengthening and toughening the stainless steel alloy, resulting in a decrease in the mechanical properties and expansion properties of the stainless steel alloy material.

[0189] (12)Compared with Example 1, Comparative Example 11 is different in that the particle size of the MgO nanoparticles is 5 μm, and the particle size of the C-Si modified CrB2 nanoparticles is 5 μm, and the particle sizes are the same, both being micron-sized. The overall performance of the alloy material is decreased. The reason is that the nano-particle strengthening phase can play roles such as heterogeneous nucleation, restricting grain growth, etc., and modifying the morphology of the secondary phase, making the secondary phase finer and more dispersed, and the efficacy of the micron-sized strengthening phase is decreased.

[0190] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-entropy alloy micro wire, characterized in that, Comprising: High-entropy stainless steel alloy; MgO nanoparticles; C-Si modified CrB2 nanoparticles; Epoxy or silicone resin; Polyurethane-molecular sieve microcapsules.

2. The high-entropy alloy microfilament according to claim 1, characterized in that, The high-entropy stainless steel alloy is Cr-Mo-Ni-Ti-Fe-M, where the composition and range of its basic components are: where M is Sn and Al, Cr 10.5 - 12.5 wt%, Mo 1.0 - 4.0 wt%, Ni 1.5 - 2.5 wt%, Ti 1.5 - 2.2 wt%, Sn 0.03 - 0.3 wt%, Al 0.1 - 0.3 wt%, and the rest is iron and inevitable impurities.

3. The high-entropy alloy micro wire according to claim 1, characterized in that, By weight: 70 - 90 parts of high-entropy stainless steel alloy; 25 - 40 parts of MgO nanoparticles; 5 - 15 parts of C-Si modified CrB2 nanoparticles; 2 - 10 parts of epoxy or silicone resin; 1 - 8 parts of polyurethane-molecular sieve microcapsules.

4. The high-entropy alloy microfilament according to claim 3, characterized in that, The volume fraction of the MgO nanoparticles is 10 - 30%.

5. The high-entropy alloy microfilament according to claim 3, characterized in that, The core of the polyurethane-molecular sieve microcapsules is molecular sieve particles loaded with a corrosion inhibitor, and the wall material is a crosslinked and cured polyurethane network.

6. The high-entropy alloy microfilament according to claim 5, wherein The corrosion inhibitor is benzotriazole, the polyurethane network is a three-dimensional network structure formed by crosslinking and curing polyurethane, and the molecular sieve particles are 4A molecular sieve particles.

7. The high-entropy alloy micro wire according to claim 3, characterized in that The epoxy resin is one of bisphenol A epoxy resin, phenolic epoxy resin, and amino epoxy resin; the silicone resin is one of methyl silicone resin, acrylic acid modified silicone resin, and phenyl silicone resin.

8. The high-entropy alloy microfilament according to claim 3, characterized in that, The particle size of the MgO nanoparticles is 0.5 - 1.2 μm, and the particle size of the C-Si modified CrB2 nanoparticles is 50 - 300 nm.

9. The preparation method of the high-entropy alloy microfilament according to any one of claims 1-7, characterized in that, Including the following steps: Step S1, preparing polyurethane-molecular sieve microcapsules; Step S2, mixing polyurethane-molecular sieve microcapsules, C-Si modified CrB2 nanoparticles with epoxy or silicone resin to obtain a prepreg; Step S3, preparing an alloy material by vacuum pressure impregnation casting; Step S4, heat-treating the obtained alloy material.

10. The preparation method of the high-entropy alloy microfilament according to claim 9, characterized in that, Step S2 includes the following steps: First, stir and mix the epoxy or silicone resin with a curing agent at 60 ± 5 °C; Second, add polyurethane-molecular sieve microcapsules, C-Si modified CrB2 nanoparticles, and stir gently at 40 ± 2 °C; Then, coat the mixture on a glass fiber cloth; Finally, vacuum dry at room temperature for 12 hours.

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