阅读说明：本技术 一种CrAlNbTiVZr高熵合金材料及其制备方法 (CrAlNbTiVZr high-entropy alloy material and preparation method thereof ) 是由 肖逸锋 刘茂 吴靓 张乾坤 陈宇 陈愚 于 2020-12-16 设计创作，主要内容包括：本发明涉及一种的CrAlNbTiVZr高熵合金材料及其制备方法,其元素成分为等摩尔比1:1:1:1:1:1的CrAlNbTiVZr,其铸态组织由BCC和HCP固溶体及少量Laves相组成。其制备方法如下：(1)超声处理：用丙酮溶液和无水乙醇清洗各材料备用；(2)称量：以等摩尔比称取各材料；(3)熔炼：使用非自耗真空电弧熔炼炉对称量配好的材料进行多次重复熔炼制备铸态高熵合金。(4)热处理：采用真空管式加热炉对铸态高熵合金进行980-1100℃,保温2-4h的均匀化退火。退火处理提高了组织的均匀性,并析出了弥散分布的细小颗粒。该合金具有优异的耐高温性能,在高温结构领域有着广泛的应用前景。(The invention relates to a CrAlNbTiVZr high-entropy alloy material and a preparation method thereof, wherein the element components of the CrAlNbTiVZr high-entropy alloy material are CrAlNbTiVZr with an equal molar ratio of 1:1:1:1:1:1, and the as-cast structure of the CrAlNbTiVZr high-entropy alloy material consists of a BCC and HCP solid solution and a small amount of Laves phase. The preparation method comprises the following steps: (1) ultrasonic treatment: cleaning each material with acetone solution and absolute ethyl alcohol for later use; (2) weighing: weighing the materials according to an equimolar ratio; (3) smelting: and repeatedly smelting the weighed and proportioned material for many times by using a non-consumable vacuum arc smelting furnace to prepare the as-cast high-entropy alloy. (4) And (3) heat treatment: and carrying out homogenization annealing on the cast-state high-entropy alloy at 980-1100 ℃ for 2-4h by using a vacuum tube type heating furnace. The annealing treatment improves the uniformity of the structure and separates out the fine particles which are dispersed and distributed. The alloy has excellent high temperature resistance and wide application prospect in the field of high-temperature structures.)

1. The CrAlNbTiVZr high-entropy alloy material is characterized in that the molar ratio of Cr to Al to Nb to Ti to V to Zr in the high-entropy alloy material is 1:1:1:1: 1; the specific preparation method is characterized by comprising the following steps:

the method comprises the following steps: respectively cleaning Cr, Al, Nb, Ti, V and Zr metal materials with the purity of not less than 99.7 wt.% by using an ultrasonic treatment instrument, and taking out for later use after cleaning; wherein, the forms of the six materials of Cr, Al, Nb, Ti, V and Zr are all sheet, block or large particle except powder.

Step two: in order to ensure the accuracy of the experiment and reduce the experimental error, a ten-thousandth electronic balance scale is adopted for weighing, the Cr material, the Al material, the Nb material, the Ti material, the V material and the Zr material which are cleaned by ultrasonic treatment in the step one are accurately weighed according to the equal molar ratio of 1:1:1:1:1, and the materials are waited for smelting.

Step three: opening a furnace door of the non-consumable vacuum arc melting furnace, putting the raw materials weighed and proportioned in the second step into a copper mold crucible of the non-consumable vacuum arc melting furnace, stacking the raw materials layer by layer in a mode that the material with the lowest melting point is placed at the lowest layer and the material with the highest melting point is placed at the uppermost layer, placing pure titanium particles in a melting tank at the middle, closing the furnace door after the placement is finished, and screwing a sample chamber sealing knob.

Step four: opening the vacuum pump, vacuumizing the sample chamber until the vacuum degree is lower than 5.0 multiplied by 10^-3Introducing high-purity argon to 0.05MPa, vacuumizing again to a vacuum degree lower than 5.0 × 10^-3MPa; the above operation is repeated several times, and the sample chamber is sufficiently cleaned to reduce the content of impurity gases.

Step five: after the sample chamber is fully cleaned, argon is injected to reach half atmospheric pressure, and arc starting smelting is started. Smelting pure titanium particles, consuming residual oxygen in a sample chamber as much as possible, and then smelting samples in other copper mold crucibles one by one. Repeatedly melting each sample for 6-8 times, turning over the sample after each melting, wherein the melting time is 2-3min each time, so as to ensure that all elements are uniformly mixed. And cooling along with the furnace to obtain the as-cast CrAlNbTiVZr high-entropy alloy material.

Step six: and putting the as-cast high-entropy alloy obtained by smelting into a vacuum tube heating furnace for carrying out homogenization annealing at 980-1100 ℃ for 2-4 h. And cooling along with the furnace to obtain the CrAlNbTiVZr high-entropy alloy material.

2. A preparation method of a CrAlNbTiVZr high-entropy alloy material,

the method is characterized by comprising the following steps:

the method comprises the following steps: respectively cleaning Cr, Al, Nb, Ti, V and Zr metal materials with the purity of not less than 99.7 wt.% by using an ultrasonic treatment instrument, and taking out for later use after cleaning; wherein, the forms of the six materials of Cr, Al, Nb, Ti, V and Zr are all sheet, block or large particle except powder.

Step two: in order to ensure the accuracy of the experiment and reduce the experimental error, a ten-thousandth electronic balance scale is adopted for weighing, the Cr material, the Al material, the Nb material, the Ti material, the V material and the Zr material which are cleaned by ultrasonic treatment in the step one are accurately weighed according to the equal molar ratio of 1:1:1:1:1, and the materials are waited for smelting.

Step three: opening a furnace door of the non-consumable vacuum arc melting furnace, putting the raw materials weighed and proportioned in the second step into a copper mold crucible of the non-consumable vacuum arc melting furnace, stacking the raw materials layer by layer in a mode that the material with the lowest melting point is placed at the lowest layer and the material with the highest melting point is placed at the uppermost layer, placing pure titanium particles in a melting tank at the middle, closing the furnace door after the placement is finished, and screwing a sample chamber sealing knob.

Step four: opening the vacuum pump, vacuumizing the sample chamber until the vacuum degree is lower than 5.0 multiplied by 10^-3Introducing high-purity argon to 0.05MPa, vacuumizing again to a vacuum degree lower than 5.0 × 10^-3MPa; the above operation is repeated several times, and the sample chamber is sufficiently cleaned to reduce the content of impurity gases.

Step five: after the sample chamber is fully cleaned, argon is injected to reach half atmospheric pressure, and arc starting smelting is started. Smelting pure titanium particles, consuming residual oxygen in a sample chamber as much as possible, and then smelting samples in other copper mold crucibles one by one. Repeatedly melting each sample for 6-8 times, turning over the sample after each melting, wherein the melting time is 2-3min each time, so as to ensure that all elements are uniformly mixed. And cooling along with the furnace to obtain the as-cast CrAlNbTiVZr high-entropy alloy material.

Step six: and putting the as-cast high-entropy alloy obtained by smelting into a vacuum tube heating furnace for carrying out homogenization annealing at 980-1100 ℃ for 2-4 h. And cooling along with the furnace to obtain the CrAlNbTiVZr high-entropy alloy material.

Technical Field

The invention relates to a high-entropy alloy material and a preparation method thereof, in particular to a CrAlNbTiVZr high-entropy alloy material and a preparation method thereof, belonging to the technical field of alloy material preparation.

Background

In the 90 s of the 20 th century, Taiwan scholars in China originally proposed a novel alloy design concept, namely multi-principal element alloy. The multi-principal element alloy is an alloy with more than 5 constituent elements and 5 to 35 atomic percent of each main element. The alloy has many component types and high content, and the mixed entropy of the atomic arrangement is high, so the multi-principal-element alloy is also called multi-principal-element high-entropy alloy. The multi-principal-element high-entropy alloy breaks through the traditional alloy design mode based on one alloy element, can obtain a combined alloy with the microstructure simplification, the nanometer precipitate, the amorphous structure, the nanometer crystal grain and other tissue characteristics and excellent performances of high hardness, wear resistance, high strength, corrosion resistance, high-temperature oxidation resistance, tempering softening resistance and the like by adjusting the alloy components, and has very wide application in industrial production. The CrAlNbTiVZr high-entropy alloy prepared by the method has a single body-centered cubic structure, has the advantages of high hardness, strong high-temperature oxidation resistance, high-temperature softening resistance and the like, and has considerable research value and development potential in the high-temperature field.

Disclosure of Invention

The invention aims to provide a CrAlNbTiVZr high-entropy alloy material and a preparation method thereof. The alloy has a simple body-centered cubic structure, has the characteristics of good room temperature plasticity and high temperature strength, and can be in service at high temperature for a long time.

The technical scheme adopted by the invention to solve the technical problems is as follows: a high-entropy alloy material comprises CrAlNbTiVZr, wherein the molar ratio of Cr to Al to Nb to Ti to V to Zr is 1:1:1:1: 1. The purity of Cr, Al, Nb, Ti, V and Zr materials adopted by the high-entropy alloy is not less than 99.7 wt.%, and the raw materials are all in the form of flakes, blocks or large particles except powder.

The technical solution adopted by the present invention to solve the above technical problems further includes: a preparation method of a high-entropy alloy material with a CrAlNbTiVZr component is characterized by comprising the following steps:

the method comprises the following steps: respectively cleaning Cr, Al, Nb, Ti, V and Zr metal materials with the purity of not less than 99.7 wt.% by using an ultrasonic treatment instrument, and taking out for later use after cleaning; wherein, the forms of the six materials of Cr, Al, Nb, Ti, V and Zr are all sheet, block or large particle except powder.

Step two: in order to ensure the accuracy of the experiment and reduce the experimental error, a ten-thousandth electronic balance scale is adopted for weighing, the Cr material, the Al material, the Nb material, the Ti material, the V material and the Zr material which are cleaned by ultrasonic treatment in the step one are accurately weighed according to the equal molar ratio of 1:1:1:1:1, and the materials are waited for smelting.

Step three: opening a furnace door of the non-consumable vacuum arc melting furnace, putting the raw materials weighed and proportioned in the second step into a copper mold crucible of the non-consumable vacuum arc melting furnace, stacking the raw materials layer by layer in a mode that the material with the lowest melting point is placed at the lowest layer and the material with the highest melting point is placed at the uppermost layer, placing pure titanium particles in a melting tank at the middle, closing the furnace door after the placement is finished, and screwing a sample chamber sealing knob.

Step four: opening the vacuum pump, vacuumizing the sample chamber until the vacuum degree is lower than 5.0 multiplied by 10^-3Introducing high-purity argon to 0.05MPa, vacuumizing again to a vacuum degree lower than 5.0 × 10^-3MPa; the above operation is repeated several times, and the sample chamber is sufficiently cleaned to reduce the content of impurity gases.

Step five: after the sample chamber is fully cleaned, argon is injected to reach half atmospheric pressure, and arc starting smelting is started. Smelting pure titanium particles, consuming residual oxygen in a sample chamber as much as possible, and then smelting samples in other copper mold crucibles one by one. Repeatedly melting each sample for 6-8 times, turning over the sample after each melting, wherein the melting time is 2-3min each time, so as to ensure that all elements are uniformly mixed. And cooling along with the furnace to obtain the as-cast CrAlNbTiVZr high-entropy alloy material.

Step six: and putting the as-cast high-entropy alloy obtained by smelting into a vacuum tube heating furnace for carrying out homogenization annealing at 980-1100 ℃ for 2-4 h. And cooling along with the furnace to obtain the CrAlNbTiVZr high-entropy alloy material.

The invention has the beneficial effects that:

the invention provides a CrAlNbTiVZr high-entropy alloy material, which mainly comprises a simple BCC solid solution phase and a Laves phase, and has uniform alloy structure. The alloy has good strength and hardness at room temperature and high temperature, has good high temperature resistance, and has wide application prospect in the high temperature field.

2. The invention provides a method for preparing a high-entropy alloy by a non-consumable vacuum arc melting process, which is used for preparing a high-entropy alloy material with high toughness, excellent corrosion resistance and high temperature resistance, makes up for the defects of the traditional alloy, has excellent mechanical properties at room temperature and high temperature, and meets the application requirements of the corrosion-resistant and high-temperature-resistant material.

3. The invention provides an annealing treatment process for an as-cast high-entropy alloy through a vacuum tube type heating furnace, which achieves the aim of more uniformization of tissues and components and can separate out dispersed fine particles to strengthen the strength and hardness of the alloy.

Drawings

FIG. 1 is a Scanning Electron Microscope (SEM) photograph of a CrAlNbTiVZr high-entropy alloy of the invention;

Detailed Description

The following specific examples are provided to illustrate the manner and process capabilities of the present invention, and other advantages and benefits of the present invention will become apparent to those skilled in the art from the disclosure herein.

1, designing CrAlNbTiVZr high-entropy alloy components.

The embodiment is a CrAlNbTiVZr high-entropy alloy consisting of six elements including Cr, Al, Nb, Ti, V and Zr, wherein the molar ratio of Cr to Al to Nb to Ti to V to Zr is 1:1:1:1: 1.

And 2, preparing the CrAlNbTiVZr high-entropy alloy.

The preparation of the high-entropy alloy is the most critical step and comprises the following steps:

1) preparing raw materials: the alloy smelting raw materials adopted by the invention are high-purity (the purity is not less than 99.5%) Cr, Al, Nb, Ti, V and Zr materials, and the shapes of the used raw materials are all sheet, block or large particle except powder.

2) Ultrasonic treatment: placing Cr, Al, Nb, Ti, V and Zr materials into a container, adding an acetone solution, placing the container in an ultrasonic oscillator for cleaning for 15-30 min, pouring ethanol after oscillation, repeating the same steps once, and then placing the container in a drying box for drying to obtain the Cr, Al, Nb, Ti, V and Zr materials after ultrasonic treatment.

3) Weighing: the Cr, Al, Nb, Ti, V and Zr materials are accurately weighed and proportioned according to the equimolar proportion and are prepared for smelting and preparing the alloy.

4) Smelting and annealing treatment: firstly, placing weighed materials in a copper mold crucible, placing pure titanium particles in a most middle smelting tank, closing a furnace door after the placing is finished, and screwing a sample chamber sealing knob; ② starting vacuum pump to vacuumize the sample chamber until the vacuum degree is lower than 5.0X 10^-3Introducing high-purity argon to 0.05MPa, vacuumizing again to a vacuum degree lower than 5.0 × 10^-3MPa; repeating the above operations for several times; the purpose of repeated vacuum pumping is gas washing, so that impurity gas in the smelting furnace is minimized as much as possible; filling argon until the pressure in the furnace reaches about half atmospheric pressure after the gas is washed, and then opening an arc power supply to prepare for smelting; melting the pure titanium particles before melting the sample, wherein the purpose is to consume residual oxygen in the furnace; fourthly, in the smelting process, in order to enable the raw materials to be mixed evenly, after the alloy is smelted each time, the electric arc is kept for 150 seconds, the alloy block is turned over after being cooled, and the operation is repeated for more than 5 to 8 times; stopping smelting after smelting for more than 5 to 8 times, opening the furnace after the alloy is cooled to room temperature along with the furnace, and taking out a sample to finally obtain a CrAlNbTiVZr high-entropy alloy ingot; sixthly, putting the as-cast high-entropy alloy obtained after smelting into a vacuum tube type heating furnace, heating to 980-1100 ℃, preserving the heat for 2-4h, and then cooling the furnace to room temperature to obtain the CrAlNbTiVZr high-entropy alloy after homogenizing annealing.

3. Structure and performance analysis of CrAlNbTiVZr high-entropy alloy

High-entropy alloy SEM microstructure of annealed CrAlNbTiVZr

(1) And (4) microscopic structure analysis.

Cutting the obtained CrAlNbTiVZr high-entropy alloy subjected to homogenizing annealing treatment into square samples with the size of 4mm multiplied by 3mm by utilizing linear cutting, carefully grinding the samples by using metallographic abrasive paper of 800#, 1200#, 1500# and 2000#, polishing by using a polishing machine, and observing the tissue morphology of the sample by using a scanning electron microscope. As shown in FIG. 1, the crystal grains generated by the CrAlNbTiVZr high-entropy alloy are in a dendritic form and have fine black particles dispersed and distributed in a matrix.

(2) And (5) micro-hardness determination and analysis.

The obtained ingot was cut into square samples of 4mm × 4mm × 3mm size by wire cutting, and the samples were carefully ground with metallographic sandpaper of 800#, 1200#, 1500# and 2000# in this order and polished with a polishing machine. The hardness of the test specimens was measured using a microhardness tester model HV-1000, with a test force of 9.807N (1kgf) and a load of 15 s. And selecting 10 different positions for measuring the microhardness of the sample, removing the highest hardness value and the lowest hardness value, taking the average value of the rest hardness values as the microhardness value of the sample, and finally obtaining the microhardness value of the alloy, wherein the microhardness value is 849.8 HV.

Example results summary:

the invention obtains the CrAlNbTiVZr alloy after annealing treatment by adopting a heat treatment method on the basis of preparing the high-entropy alloy by vacuum melting. Al and Cr elements are added into the alloy, and because the Al and Cr elements can generate compact oxide films to cover the surface of the alloy and prevent oxygen from directly contacting the alloy, the oxidation resistance of the alloy is improved, the structure is more uniform by a homogenization heat treatment method, and hard particles are dispersed and distributed on a matrix, so that the strength and the hardness of the alloy are improved. The original performance of the matrix is greatly improved by heat treatment, the toughness, plasticity and hardness of the alloy are superior to those of other traditional high-entropy alloys, and the alloy has great development potential and scientific research value.

The above-described embodiments are merely exemplary and not intended to limit the present invention in any way, and any simple modifications, equivalent variations and modifications made to the above-described embodiments in accordance with the technical spirit of the present invention are within the scope of the present invention.