GB2606330A

GB2606330A - High-entropy alloy containing boron and rare earth and magnetic field treatment method therefor

Info

Publication number: GB2606330A
Application number: GB2212502.5A
Authority: GB
Inventors: Li Guirong; Wang Hongming
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2020-02-28
Filing date: 2021-02-24
Publication date: 2022-11-02
Anticipated expiration: 2041-02-24
Also published as: GB2606330B; CN111235458B; CN111235458A; WO2021169985A1; GB202212502D0

Abstract

A high-entropy alloy containing boron and rare earth and a magnetic field treatment method therefor. The whole treatment process is divided into two parts, i.e. pulse magnetic field heat treatment and low-temperature static magnetic field treatment. The pulse magnetic field heat treatment has high treatment energy and high treatment efficiency, and can effectively improve the conversion rate of a hard particle phase. The low-temperature static magnetic field further precipitates a particle phase on the basis of inhibiting the growth of grains, significantly refines the grains at the same time, and can effectively relieve internal stress, so that mechanical properties and anti-abrasion properties of the material are greatly improved, and the material has a wide range of applications.

Description

HIGH-ENTROPY ALLOY CONTAINING BORON AND RARE EARTH AND

MAGNETIC FIELD TREATMENT METHOD THEREFOR

TECHNICAL FIELD

The present disclosure belongs to the technical fields of rare earth metal (REM) materials and material heat treatment, and relates to a boron-containing and rare earth-containing high-entropy alloy (REA) and a toughening treatment method therefor.

BACKGROUND

Subzero treatment is a new technique developed on the basis of ordinary cold treatment (0°C to -100°C) in the 1960s, As early as more than 100 years ago, the ordinary cold treatment had been applied to clock and watch parts, castings, and the like, and it was found that the ordinary cold treatment could significantly improve the strength, wear resistance, dimensional stability, and service life of a material. The subzero treatment (at a temperature of lower than -130°C) was put forward for the first time in the United States in 1955, and many studies have shown that the subzero treatment leads to a better effect than the ordinary cold treatment. However, a subzero treatment process for HEAs is rarely reported.

REA is a multi-component alloy material with a unique design concept proposed in the early 21st century, which is a solid solution alloy fabricated by mixing five or more elements in an equimolar or nearly-equimolar ratio. Studies have shown that HEAs have high strength and hardness and excellent wear resistance, corrosion resistance, and dimensional stability, and can be used for precision components such as clock and watch parts, micro shafts, medical bone nails, and fiber-optic tail handles on a large scale. Common methods to improve the performance of HEAs include alloying element adjustment and heat treatment, or a special method is used to fabricate an HEA. Most of these methods are complicated and difficult to implement, and lead to limited improvement on the performance. Therefore, the present disclosure applies a magnetic field to heat treatment and subzero treatment processes of a boron-containing and rare earth-containing HEA. With the special advantages of the magnetic field, the contradiction between the strength and toughness of an alloy material is overcome and the mechanical performance and wear resistance of the boron-containing and rare earth-containing 1-TEA are both improved. The above method involves simple operations and can lead to obvious performance improvement, which is of great significance for the large-scale application of ffEAs in the future.

SUMMARY

In order to solve the problem that it is impossible to simultaneously improve the strength and plasticity of an HEA material in the prior art, the present disclosure provides a method for simultaneously improving the mechanical performance and wear resistance of a boron-containing and rare earth-containing FLEA through the coupling of a static magnetic field, a high pulsed magnetic field, and a temperature field.

The present disclosure adopts the following specific technical solutions.

A magnetic field treatment method for a boron-containing and rare earth-containing HEA is provided, including: subjecting the boron-containing and rare earth-containing HEA to a heat treatment under a high pulsed magnetic field, cooling the boron-containing and rare earth-containing HEA to a room temperature, and subjecting the boron-containing and rare earth-containing HEA to a subzero treatment under a static magnetic field; and after the subzero treatment is completed, warming the boron-containing and rare earth-containing HEA to the room temperature by placing the boron-containing and rare earth-containing HEA in air, such that a nanoparticle phase is generated that is beneficial to simultaneously improve a mechanical performance and a wear resistance of the boron-containing and rare earth-containing BEA, an internal residual stress is eliminated, and a service life is increased.

Further, the magnetic field treatment method for the boron-containing and rare earth-containing HEA includes the following steps: step (1): placing a boron-containing and rare earth-containing HEA product manufactured in an alumina crucible, and placing the alumina crucible in a tube furnace, setting a heating rate, a holding temperature, and a holding time, followed by evacuating, and introducing a protective gas; and running a program for the heat treatment; step (2): after the temperature is raised to the holding temperature for the heat treatment, applying a magnetic field with a magnetic field pulse frequency of 0.1 Hz to 1,000 Hz and a magnetic field intensity of 0.1 T to 10 T; step (3): after the heat treatment is completed, turning off the magnetic field, taking out the boron-containing and rare earth-containing HEA product, cooling the boron-containing and rare earth-containing HEA product to the room temperature in the air, and subjecting a surface of the boron-containing and rare earth-containing HEA product to cleaning, finishing, and polishing treatments; step (4): placing the boron-containing and rare earth-containing 1-1EA product in a fixture, clamping a strong magnet at each of two ends of the fixture to obtain a static magnetic field device, wrapping the static magnetic field device with a thermally-insulating fibrofelt, and immersing the static magnetic field device in -180°C to -190°C liquid nitrogen for the subzero treatment, where the strong magnet has a surface magnetic field intensity of 0.1 T to 2 T and a holding time for the subzero treatment is 1 h to 120 h; and step (5): taking the boron-containing and rare earth-containing HEA product out of the fixture, and warming the boron-containing and rare earth-containing HEA product to the room temperature in the air.

Further, in the step (1), an initial heating rate of the tube furnace is set to 5°C/min, and after a temperature is raised to 400°C, the heating rate of the tube furnace is set to 2°C/min; when the boron-containing and rare earth-containing FLEA has a thickness of less than or equal to 10 mm, that is, the boron-containing and rare earth-containing HEA product is a light and thin product, the heat treatment is conducted at 400°C to 450°C for 0.1 h to 2 h; and when the boron-containing and rare earth-containing HEA has a thickness of greater than 10 mm, that is, the boron-containing and rare earth-containing HEA product is a thick and heavy product, the heat treatment is conducted at 450°C to 550°C for 2 h to 5 h. Although a too-long heat treatment time or a too-high heat treatment temperature can improve a conversion rate of a precipitated phase, coarse grains are formed to affect the mechanical performance, and a thin and light component even undergoes high-temperature deformation. A too-low heat treatment temperature or a too-short heat treatment time will cause a low conversion rate of a precipitated phase, thereby affecting the service performance.

Further, in the step (4), when the boron-containing and rare earth-containing HEA has a thickness of less than or equal to 10 mm, that is, the boron-containing and rare earth-containing HEA product is a light and thin product, the strong magnet with the surface magnetic field intensity of 0.1 T to 1 T is adopted; and when the boron-containing and rare earth-containing HEA has a thickness of greater than 10 mm, that is, the boron-containing and rare earth-containing REA product is a thick and heavy product, the strong magnet with the surface magnetic field intensity of greater than 1 T is adopted. When a strong magnet with a low magnetic field intensity is used for a thick and heavy product, the transformation of an internal organization cannot be driven due to insufficient magnetic field energy, such that the effect of the magnetic field of subzero treatment is weakened.

Further, in the step (4), when the boron-containing and rare earth-containing HEA has a thickness of less than or equal to 10 mm, that is, the boron-containing arid rare earth-containing HEA product is a light and thin product, the holding time for the subzero treatment is 1 h to 60 h; and when the boron-containing and rare earth-containing HEA has a thickness of greater than 10 mm, that is, the boron-containing and rare earth-containing FLEA product is a thick and heavy product, the holding time for the subzero treatment is prolonged to 60 h to 120 h. This is because the performance of the light and thin product cannot be significantly improved when the holding time for the subzero treatment exceeds a specified value. For the thick and heavy product, if the holding time for the subzero treatment is too short, a degree of grain refinement and a conversion rate of a precipitated phase will be low, resulting in an insignificant treatment effect.

Further, the boron-containing and rare earth-containing HEA includes main components consisting of Fe, Co, Ni, Cu, B, and Y, and has an atomic ratio expression of FeCoNit n _.50th Y in, where 0 < n < 1.2 and 0 < m < 0.5. However, the boron-containing and rare earth-containing HEA is not limited to the above components, and other quenching and tempering elements can be added. A rare-earth element (REE) is not limited to yttrium, and another REE such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), or erbium (Er) can be adopted.

Further, the REE yttrium is replaced by lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), or erbium (Er).

Further, the boron-containing and rare earth-containing HEA further includes a quenching and tempering element.

Further, the boron-containing and rare earth-containing HEA is manufactured by one of microwave sintering, copper mould suction casting, magnetron sputtering, and powder metallurgy.

A boron-containing and rare earth-containing HEA obtained by the magnetic field treatment method for the boron-containing and rare earth-containing HEA is provided.

The principle of the present disclosure: A phase transformation driving force produced by a magnetic field can promote the generation of a hard particle phase in a soft phase rare earth-rich phase in the boron-containing and rare earth-containing HEA; and the generation of the particle phase will increase the strength of the rare earth-rich phase to improve the overall mechanical performance and wear resistance of the alloy. A heat treatment under a pulsed magnetic field has high energy and high treatment efficiency, but will also cause the rapid growth of boride grains, and coarse boride grains will make the alloy brittle and reduce the toughness of the alloy. Therefore, in the early stage of the magnetic field treatment, a heat treatment under a pulsed magnetic field is conducted to improve the efficiency, and in the later stage of the magnetic field treatment, a subzero treatment under a static magnetic field is conducted to further optimize the structure. A coupling effect of the subzero field and the static magnetic field can also promote the generation of a hard particle phase, refine grains, and alleviate an internal residual stress, but causes problems such as low conversion efficiency and excessive consumption. Therefore, the combination of the heat treatment under a pulsed magnetic field and the subzero treatment under a static magnetic field can maximize a high-quality effect of each treatment and avoid adverse reactions, and is a very effective post-treatment method, which provides promising prospects for the future development of HEAs.

Compared with the prior art, the present disclosure has the following significant advantages and effects.

(1) The method of the present disclosure can be used for a toughening treatment of a boron-containing and rare earth-containing HEA product obtained after precision machining, which does not affect an alloy composition, does not damage a surface layer and stnicture of the product, and has outstanding advantages over the existing chemical plating, deposition, and machining deformation strengthening.

(2) The liquid nitrogen and static magnetic field used in the treatment neither pollute the environment nor affect the health of operators; and an operation process can be controlled and has high safety and low cost. Therefore, the method of the present disclosure is an environmentally-friendly material processing method.

(3) The treatment method of the present disclosure can significantly adjust a structure of the boron-containing and rare earth-containing HEA, such that the strength and toughness of the boron-containing and rare earth-containing HEA can be improved and the wear resistance of the alloy is significantly improved. Experimental results show that, under the same conditions, the pulsed magnetic field can increase a conversion rate of a beneficial hard particle phase by up to 18% on average, the static magnetic field can increase the conversion rate by 8.7%, and the temperature field can increase the conversion rate by 4.3%, which is the lowest. Without a magnetic field, the heat treatment alone cannot produce a significant effect; and the magnetic field treatment alone also cannot significantly improve the performance of the material. The generation and growth of the hard particle phase can only be achieved through the combination of the temperature field and the magnetic field, thereby greatly improving the comprehensive mechanical performance and wear resistance of the alloy.

In summary, the method of the present disclosure greatly expands an application range of HEAs, further taps the performance potential of the existing HEAs, reduces the production cost, and has high market economic benefits.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the magnetic field device in the present disclosure.

FIG. 2 is a scanning electron microscopy (SEM) electron diffraction pattern of FeCoNil 5Cul130.5Y0, that is annealed at 400°C under a pulsed magnetic field for 0.5 h and then subjected to a subzero treatment under a 0.2 T static magnetic field for 5 h. FIG. 3 is an SEM image of FeCoNi1.5CuB00Y0.7 that is annealed at 400°C under a pulsed magnetic field for 0.5 h and then subjected to a subzero treatment under a 0.2 T static magnetic

field for 5 h after a friction and wear test.

FIG. 4 is an SEM electron diffraction pattern of FeCoNii 5CuB0.5Y0 2 that is annealed at 400°C under a pulsed magnetic field for 2 h and then subjected to a subzero treatment under a 0.2 T static magnetic field for 30 h. FIG. 5 is an SEM image of FeCoNii.5Cul30.5Y0.2 that is annealed at 400°C under a pulsed magnetic field for 2 h and then subjected to a subzero treatment under a 0.2 T static magnetic field for 30 h after a friction and wear test.

FIG. 6 is an SEM electron diffraction pattern of FeCoNii.5Cul30.5Y0.2 that is annealed at 450°C under a pulsed magnetic field for 2 h and then subjected to a subzero treatment under a 1 T static magnetic field for 30 h. FIG. 7 is an SEM image of FeCoNii.5CuH0.5Y0.2 that is annealed at 450°C under a pulsed magnetic field for 2 h and then subjected to a subzero treatment under a 1 T static magnetic field for 30 h after a friction and wear test.

In the figures: 1 represents a first strong magnet, 2 represents a fixture, 3 represents a second strong magnet, and 4 represents a product.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure will be further described below in conjunction with the accompanying drawings and specific examples, but the protection scope of the present disclosure is not limited thereto.

In the magnetic field treatment method for the boron-containing and rare earth-containing HEA according to the present disclosure, a phase transformation driving force produced by a magnetic field can promote the generation of a hard particle phase in a soft phase rare earth-rich phase in the boron-containing and rare earth-containing HEA; the generation of the particle phase will increase the strength of the rare earth-rich phase to improve the overall mechanical performance and wear resistance of the alloy; and the mechanical performance and wear resistance of the boron-containing and rare earth-containing REA can be simultaneously improved. In the magnetic field treatment method, the boron-containing and rare earth-containing HEA is subjected to a heat treatment under a high pulsed magnetic field, then cooled to room temperature, and then subjected to a subzero treatment under a static magnetic field, and after the subzero treatment is completed, the boron-containing arid rare earth-containing HEA is warmed to room temperature in the air, such that a nanoparticle phase is generated that is beneficial to simultaneously improve a mechanical performance and a wear resistance of the alloy, an internal residual stress is eliminated, and a service life is increased. A magnetic field device used is shown in FIG. 1, which includes two strong magnets (namely, a first strong magnet 1 and a second strong magnet 2) that are arranged oppositely, and a fixture 2 for clamping a product 4.

A heat treatment under a pulsed magnetic field has high energy and high treatment efficiency, but will also cause the rapid growth of boride grains, and coarse boride grains will make the alloy brittle and reduce the toughness of the alloy. Therefore, in the early stage of the magnetic field treatment, a heat treatment under a pulsed magnetic field is conducted to improve the efficiency, and in the later stage of the magnetic field treatment, a subzero treatment under a static magnetic field is conducted to further optimize the structure. A coupling effect of the subzero field and the static magnetic field can also promote the generation of a hard particle phase, refine grains, and alleviate an internal residual stress, but causes problems such as low conversion efficiency and excessive consumption. Therefore, the combination of the heat treatment under a pulsed magnetic field and the subzero treatment under a static magnetic field can maximize a high-quality effect of each treatment and avoid adverse reactions, and is a very effective post-treatment method.

The magnetic field treatment method for the boron-containing and rare earth-containing HEA specifically includes the following steps: (I): A boron-containing and rare earth-containing HEA product manufactured is placed in an alumina crucible, and the alumina crucible is placed in a tube furnace; heat treatment process parameters such as a heating rate, a holding temperature, and a holding time are set, and the tube furnace is evacuated and introduced with a protective gas; and a program is run for a heat treatment. An initial heating rate of the tube furnace is set to 5°C/min, and after a temperature is raised to 400°C, a heating rate is set to 2°C/min. Although a too-long heat treatment time or a too-high heat treatment temperature can improve a conversion rate of a precipitated phase, coarse grains are formed to affect the mechanical performance, and a thin and light component even undergoes high-temperature deformation. A too-low heat treatment temperature or a too-short heat treatment time will cause a low conversion rate of a precipitated phase, thereby affecting the service performance. Therefore, when the boron-containing and rare earth-containing HEA to be treated has a thickness of less than or equal to 10 mm, that is, the boron-containing and rare earth-containing HEA product is a light and thin product, the heat treatment is conducted at 400°C to 450°C for 0.1 h to 2 h; and when the boron-containing and rare earth-containing HEA to be treated has a thickness of greater than 10 mm, that is, the boron-containing and rare earth-containing HEA product is a thick and heavy product, the heat treatment is conducted at 450°C to 550°C for 2 h to 5 h. (2) After a temperature is raised to the holding temperature for the heat treatment, a magnetic field is applied with a magnetic field pulse frequency of 0.1 Hz to 1,000 Hz and a

magnetic field intensity of 0.1 T to 10 T.

(3) After the heat treatment is completed, the magnetic field is turned off, the boron-containing and rare earth-containing HEA product is taken out and cooled to room temperature in the air, and a surface of the boron-containing and rare earth-containing HEA product is subjected to cleaning, finishing, and polishing treatments to improve the efficiency of the magnetic field treatment.

(4) The boron-containing and rare earth-containing HEA product is placed in a fixture, a strong magnet is clamped at each of two ends of the fixture to obtain a static magnetic field device, and the overall static magnetic field device is wrapped with a thermally-insulating fibrofelt and then immersed in -180°C to -190°C liquid nitrogen for the subzero treatment, where the strong magnet has a surface magnetic field intensity of 0.1 T to 2 T and a holding time for the subzero treatment is 1 h to 120 h. When a strong magnet with a low magnetic field intensity is used for a thick and heavy product, the transformation of an internal organization cannot be driven due to insufficient magnetic field energy, such that the effect of the magnetic field of subzero treatment is weakened. The performance of the light and thin product cannot be significantly improved when the holding time for the subzero treatment exceeds a specified value. For the thick and heavy product, if the holding time for the subzero treatment is too short, a degree of grain refinement and a conversion rate of a precipitated phase will be low, resulting in an insignificant treatment effect. When the boron-containing and rare earth-containing HEA to be treated has a thickness of less than or equal to 10 mm, that is, the boron-containing and rare earth-containing BEA product is a light and thin product, the strong magnet with the surface magnetic field intensity of 0.1 T to 1 T is adopted and the holding time for the subzero treatment is 1 h to 60 h; and when the boron-containing and rare earth-containing HEA to be treated has a thickness of greater than 10 mm, that is, the boron-containing and rare earth-containing HEA product is a thick and heavy product, the strong magnet with the surface magnetic field intensity of greater than 1 T is adopted and the holding time for the subzero treatment is prolonged to 60 h to 120 h. (5) The boron-containing and rare earth-containing HEA product is taken out of the fixture and then warmed to room temperature in the air.

The boron-containing and rare earth-containing HEA used in the magnetic field treatment method of the present disclosure includes main components consisting of Fe, Co, Ni, Cu, B, and Y, and has an atomic ratio expression of FeCoNii 5CuBY, where 0 <n < 1.2 and 0 < m < 0.5. However, the boron-containing and rare earth-containing HEA is not limited to the above components, and other quenching and tempering elements can be added. An REE is also not limited to yttrium, and another REE such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), or erbium (Er) can be adopted. The boron-containing and rare earth-containing HEA is manufactured by one of microwave sintering, copper mould suction casting, magnetron sputtering, and powder metallurgy.

In the following examples, the HEA FeCoNii.5CuB0t5Y0.2 used is a boron-containing and rare earth-containing HEA with a thickness of 6 mm, which is light and thin; and a sample fixture with the same thickness is used accordingly. A N52 NdFeB strong magnet is adopted as the strong magnet. The HEA FeCoNii.5Cuf0.5Y0.7 obtained after the subzero treatment is processed into a cylindrical sample of (I) 6*9 mm through wire cutting for a compression test. In the present disclosure, a friction and wear test is conducted with a CET-I-type friction and wear tester to verify the wear resistance of the alloy where a test sample has a size of 7*7*2.5 mm, a friction ball is a Si3N4 ball with a diameter of 4 mm, and the wear test is conducted for 30 min with a load of 100 N, a rotational speed of 220 t/m, and a slide spacing of 5 mm.

Example 1

A boron-containing and rare earth-containing HEA product manufactured was placed in an alumina crucible, and the alumina crucible was placed in a tube furnace; a holding temperature and a holding time were set to allow annealing at 400°C for 0.5 h, and then the tube furnace was evacuated and introduced with a protective gas; a program was run for a heat treatment, and after a temperature was raised to a treatment temperature, a magnetic field was applied; after the heat treatment was completed, the magnetic field was turned off, the boron-containing and rare earth-containing HEA product was taken out and cooled to room temperature in the air, and a surface of the boron-containing and rare earth-containing HEA product was subjected to cleaning, finishing, and polishing treatments to improve the efficiency of the magnetic field treatment; the boron-containing and rare earth-containing HEA product was placed in a fixture, a strong magnet was clamped at each of two ends of the fixture, and the overall static magnetic field device was wrapped with thermally-insulating fibrofelt and then immersed in -180°C to -190°C liquid nitrogen for a subzero treatment, where the strong magnet had a surface magnetic field intensity of 0.2 T and a holding time for the subzero treatment was 5 h; and the boron-containing and rare earth-containing HEA product was taken out of the fixture and then warmed to room temperature in the air.

FIG. 2 is an SEM image of FeCoNii 5CuB051/02 that is annealed at 400°C under a pulsed magnetic field for 0.5 h and then subjected to a subzero treatment under a 0.2 T static magnetic field for 5 h. Since both the subzero treatment time and the annealing treatment time are short, the morphology of the precipitated phase is not obvious. Therefore, only a rare earth-rich phase (soft phase), a boride phase, and an HEA base phase can be seen in the SEM image. The existence of the soft phase greatly limits the mechanical performance and wear resistance of the boron-containing and rare earth-containing FLEA. The alloy has a compressive strength of 1,228 Mpa (which is 2.25% higher than that of the untreated base metal (1,201 Mpa)) and a maximum compression ratio of 28.72% (which is 1.81% higher than that of the untreated base metal (28.21%)), such that the mechanical performance is not significantly improved.

FIG. 3 is an SEM image of FeCoNi 5CuB05Y0) that is annealed at 400°C under a pulsed magnetic field for 0.5 h and then subjected to a subzero treatment under a 0.2 T static magnetic field for 5 h after a friction and wear test. It can be seen from the figure that wear types mainly include abrasive wear, adhesive wear, and delamination wear; the wear scar on the left has adhesion marks in a large range, and a surface is covered with many new abrasive grains; and there is a large spalling pit on the right, and there are many irregular cracks on an edge of the spalling pit, such that, under a load action perpendicular to a wear surface, the spalling pit is likely to evolve into a new spalling area, causing increased wear loss. Therefore, the wear resistance of the alloy is not significantly improved and is still poor.

Example 2

A boron-containing and rare earth-containing HEA product manufactured was subjected to a surface treatment and then subjected to a subzero treatment and a magnetic field treatment according to the operation flow in Example 1. It should be noted that, in order to improve the treatment effect, an annealing treatment time under a pulsed magnetic field and a subzero treatment time under a static magnetic field were prolonged to 2 h and 30 h respectively. The prolongation of the subzero treatment time helped the generation of a precipitated phase, and the prolongation of the annealing treatment time helped the alleviation of an internal residual stress generated under a coupling effect of the subzero field and the static magnetic field.

FIG. 4 is an SEM image of FeCoNi15Cul30.5Y0.2 that is annealed at 400°C under a pulsed magnetic field for 2 h and then subjected to a subzero treatment under a 0.2 T static magnetic field for 30 h. It can be seen that, compared with Example 1, grains are refined and a submicron-scale hard particle phase is generated in the rare earth-rich phase. The generation of the hard particle phase helps to increase a strength of the rare earth-rich phase, thereby increasing a strength of the alloy as a whole. The alloy has a compressive strength of 1,314 Mpa (which is 9.5% higher than that of the untreated base metal) and a maximum compression ratio of 31.25% (which is 10.78% higher than that of the untreated base metal), such that the mechanical performance is relatively significantly improved.

FIG. 5 is an SEM image of FeCoNii.5CuB0.5Y0.2 that is annealed at 400°C under a pulsed magnetic field for 2 h and then subjected to a subzero treatment under a 0.2 T static magnetic field for 30 h after a friction and wear test. Wear types mainly include abrasive wear and delamination wear; irregular delamination occurs in many areas, and a fresh matrix is exposed; many abrasive grains are accumulated inside a spatting pit, which may cause a new wear scar on a surface; and the wear conditions are significantly better than that in Example 1, indicating that the generation of the submicron-scale particle phase also greatly improves the wear resistance of the alloy.

Example 3

A boron-containing and rare earth-containing REA product manufactured was subjected to a surface treatment and then subjected to a subzero treatment and a magnetic field treatment according to the operation flow in Example 2. It should be noted that, in order to further improve the treatment effect, the annealing temperature and the static magnetic field intensity were increased to 450°C and 1 T respectively. The increase of the magnetic field intensity helped the generation of a precipitated phase, and the increase of the annealing temperature helped the further effective alleviation of an internal residual stress generated under a coupling effect of the subzero field and the static magnetic field.

FIG. 6 is an SEM image of FeCoNit.5CuB0.5Y0.2 that is annealed at 450°C under a pulsed magnetic field for 2 h and then subjected to a subzero treatment under a 1 T static magnetic field for 30 h. It can be seen from the figure that the submicron-scale particle phase is further precipitated and evenly distributed in the rare earth-rich phase. The alloy has a compressive strength of 1,421 Mpa (which is 18.32% higher than that of the untreated base metal) and a maximum compression ratio of 32.71% (which is 15.95% higher than that of the untreated base metal), such that the mechanical performance is significantly improved.

FIG. 7 is an SEM image of FeCoNit.5CuB0.5Y0.2 that is annealed at 450°C under a pulsed magnetic field for 2 h and then subjected to a subzero treatment under a 1 T static magnetic field for 30 h after a friction and wear test. A wear type is abrasive wear; there is a shallow and fine furrow parallel to a wear direction, and a small number of abrasive grains remain on a surface. The wear conditions are greatly improved compared with Examples 1 and 2, which is attributed to the strengthening of a second phase resulting from the precipitation of the submicron-scale hard particle phase.

The above examples are preferred implementations of the present disclosure, but the present disclosure is not limited to the above implementations. Any obvious improvement, substitution, or modification made by those skilled in the art without departing from the essence of the present disclosure should fall within the protection scope of the present disclosure.

Claims

CLAIMSWhat is claimed is: I. A magnetic field treatment method for a boron-containing and rare earth-containing high-entropy alloy, characterized by comprising: subjecting the boron-containing and rare earth-containing high-entropy alloy to a heat treatment under a high pulsed magnetic field, cooling the boron-containing and rare earth-containing high-entropy alloy to a room temperature, and subjecting the boron-containing and rare earth-containing high-entropy alloy to a subzero treatment under a static magnetic field; and after the subzero treatment is completed, warming the boron-containing and rare earth-containing high-entropy alloy to the room temperature by placing the boron-containing and rare earth-containing high-entropy alloy in air, such that a nanoparticle phase is generated that is beneficial to simultaneously improve a mechanical performance and a wear resistance of the boron-containing and rare earth-containing high-entropy alloy, an internal residual stress is eliminated, and a service life is increased, wherein the magnetic field treatment method comprises the following steps: step (1): placing a boron-containing and rare earth-containing high-entropy alloy product manufactured in an alumina crucible, and placing the alumina crucible in a tube furnace, setting a heating rate, a holding temperature, and a holding time, followed by evacuating, and introducing a protective gas; and running a program for the heat treatment, wherein an initial heating rate of the tube furnace is set to 5°Cimin, and after a temperature is raised to 400°C, the heating rate of the tube furnace is set to 2°C/min; and the heat treatment is conducted at the holding temperature of 400°C to 550°C for 0.1 h to 5 h; step (2): after the temperature is raised to the holding temperature for the heat treatment, applying a magnetic field with a magnetic field pulse frequency of 0.1 Hz to 1,000 Hz and a magnetic field intensity of 0.1 T to 10 T; step (3): after the heat treatment is completed, turning off the magnetic field, taking out the boron-containing and rare earth-containing high-entropy alloy product, cooling the boron-containing and rare earth-containing high-entropy alloy product to the room temperature in the air, arid subjecting a surface of the boron-containing and rare earth-containing high-entropy alloy product to cleaning, finishing, and polishing treatments; step (4): placing the boron-containing and rare earth-containing high-entropy alloy product in a fixture, clamping a strong magnet at each of two ends of the fixture to obtain a static magnetic field device, wrapping the static magnetic field device with a thermally-insulating fibrofelt, and immersing the static magnetic field device in -180°C to -190°C liquid nitrogen for the subzero treatment, wherein the strong magnet has a surface magnetic field intensity of 0.1 T to 2 T and a holding time for the subzero treatment is 1 h to 120 h; and step (5): taking the boron-containing and rare earth-containing high-entropy alloy product out of the fixture, and warming the boron-containing and rare earth-containing high-entropy alloy product to the room temperature in the air 2. The magnetic field treatment method for the boron-containing and rare earth-containing high-entropy alloy according to claim 1, characterized in that in the step (1), when the boron-containing and rare earth-containing high-entropy alloy has a thickness of less than or equal to 10 mm, that is, the boron-containing and rare earth-containing high-entropy alloy product is a light and thin product, the heat treatment is conducted at 400°C to 450°C for 0.1 h to 2 h; and when the boron-containing and rare earth-containing high-entropy alloy has a thickness of greater than 10 mm, that is, the boron-containing and rare earth-containing high-entropy alloy product is a thick and heavy product, the heat treatment is conducted at 450°C to 550°C for 2 h to 5 h. 3. The magnetic field treatment method for the boron-containing and rare earth-containing high-entropy alloy according to claim 1, characterized in that in the step (4), when the boron-containing and rare earth-containing high-entropy alloy has a thickness of less than or equal to 10 mm, that is, the boron-containing and rare earth-containing high-entropy alloy product is a light and thin product, the strong magnet with the surface magnetic field intensity of 0.1 T to 1 T is adopted; and when the boron-containing and rare earth-containing high-entropy alloy has a thickness of greater than 10 mm, that is, the boron-containing and rare earth-containing high-entropy alloy product is a thick and heavy product, the strong magnet with the surface magnetic field intensity of greater than 1 T is adopted.4. The magnetic field treatment method for the boron-containing and rare earth-containing high-entropy alloy according to claim 1, characterized in that in the step (4), when the boron-containing and rare earth-containing high-entropy alloy has a thickness of less than or equal to 10 mm, that is, the boron-containing and rare earth-containing high-entropy alloy product is a light and thin product, the holding time for the subzero treatment is 1 h to 60 h; and when the boron-containing and rare earth-containing high-entropy alloy has a thickness of greater than 10 mm, that is, the boron-containing and rare earth-containing high-entropy alloy product is a thick and heavy product, the holding time for the subzero treatment is prolonged to 60 h to 120 h. 5. The magnetic field treatment method for the boron-containing and rare earth-containing high-entropy alloy according to claim 1, characterized in that the boron-containing and rare earth-containing high-entropy alloy comprises main components consisting of Fe, Co, Ni, Cu, B, and Y, and has an atomic ratio expression of FeCoNiL5CuBnYm, wherein 0 <n < 1.2 and 0< m < 0.5.6. The magnetic field treatment method for the boron-containing and rare earth-containing high-entropy alloy according to claim 5, characterized in that a rare-earth element yttrium is replaced by lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), or erbium (Er).7. The magnetic field treatment method for the boron-containing and rare earth-containing high-entropy alloy according to claim 5, characterized in that the boron-containing and rare earth-containing high-entropy alloy further comprises a quenching and tempering element.8. The magnetic field treatment method for the boron-containing and rare earth-containing high-entropy alloy according to claim 5, characterized in that the boron-containing and rare earth-containing high-entropy alloy is manufactured by one of microwave sintering, copper mould suction casting, magnetron sputtering, and powder metallurgy.9. A boron-containing and rare earth-containing high-entropy alloy obtained by the magnetic field treatment method for the boron-containing and rare earth-containing high-entropy alloy according to any one of claims 1 to 8.