阅读说明：本技术 一种以金属间化合物为基的高熵合金及其制备方法 (High-entropy alloy based on intermetallic compound and preparation method thereof ) 是由 刘亮 姚昆达 商剑 张越 赵作福 王冰 齐锦刚 于 2019-12-10 设计创作，主要内容包括：本发明公开了一种以金属间化合物为基的高熵合金及其制备方法,该合金由如下原子百分比组成:钛0.9～1.1；锆0.9～1.1；铪0.9～1.1；铁0.7～0.8；钴0.7～0.8；镍0.7～0.8；铜0.7～0.8；其中,钛、锆和铪元素等摩尔比,铁、钴、镍和铜元素等摩尔比。一种以金属间化合物为基的高熵合金的制备方法包括:a、称取；b、放入电弧炉中；c、抽真空；d、用140～160A的电流持续80～100s,冷却后,再次翻转形成的合金锭,重复翻转熔炼5～7次；e、吸铸,制得所述以金属间化合物为基的高熵合金。发明的有益效果是:具有单相B2晶体结构、较高的热稳定性、良好的屈服强度、抗压强度和高硬度。(The invention discloses a high-entropy alloy based on intermetallic compounds and a preparation method thereof, wherein the alloy comprises the following components in atomic percentage of 0.9-1.1 of titanium; 0.9-1.1% of zirconium; 0.9 to 1.1 parts of hafnium; 0.7-0.8% of iron; 0.7-0.8% of cobalt; 0.7-0.8% of nickel; 0.7 to 0.8 of copper; wherein, the molar ratio of titanium, zirconium and hafnium elements is equal, and the molar ratio of iron, cobalt, nickel and copper elements is equal. A preparation method of high-entropy alloy based on intermetallic compounds comprises a, weighing; b. putting the mixture into an electric arc furnace; c. vacuumizing; d. continuously using current of 140-160A for 80-100 s, cooling, overturning the formed alloy ingot again, and repeatedly overturning and smelting for 5-7 times; e. and (4) carrying out suction casting to obtain the high-entropy alloy based on the intermetallic compound. The invention has the advantages of single-phase B2 crystal structure, high thermal stability, good yield strength, compressive strength and high hardness.)

1. An intermetallic compound based high entropy alloy, characterized in that it consists of the following molar ratios:

0.9 to 1.1 parts of titanium;

0.9-1.1% of zirconium;

0.9 to 1.1 parts of hafnium;

0.7-0.8% of iron;

0.7-0.8% of cobalt;

0.7-0.8% of nickel;

0.7 to 0.8 of copper;

wherein, the molar ratio of titanium, zirconium and hafnium elements is equal, and the molar ratio of iron, cobalt, nickel and copper elements is equal.

2. An intermetallic compound-based high entropy alloy as claimed in claim 1 consisting of the molar ratios titanium zirconium hafnium iron cobalt nickel copper 1:1:1:0.75:0.75:0.75: 0.75.

3. A method for the preparation of an intermetallic compound based high entropy alloy according to any of claims 1-2, characterized in that it comprises the following steps:

a. weighing a titanium block, a zirconium block, a hafnium block, an iron block, a cobalt block, a nickel block and a copper block according to a molar ratio of titanium, zirconium, hafnium, cobalt, nickel and copper of 0.9-1.1: 0.7-0.8; wherein, the molar ratio of titanium, zirconium and hafnium elements is equal, and the molar ratio of iron, cobalt, nickel and copper elements is equal;

b. putting the weighed copper block, nickel block, cobalt block, iron block, titanium block, zirconium block and hafnium block into a smelting pool I of a water-cooled copper mould of an electric arc furnace;

c. vacuumizing the electric arc furnace, and adjusting the vacuum degree in the furnace body to 5 x 10^-3～7×10^-3Pa, filling argon gas with one atmosphere into the furnace body, then discharging the argon gas, and adjusting the vacuum degree in the furnace body to 5 x 10^-3～7×10^-3Pa, filling argon gas with one atmosphere into the furnace body again;

d. moving the electrode above the smelting pool I, striking an arc by using a current of 50A, continuously smelting for 80-100 s by using a current of 140-160A, cooling to form an alloy ingot, turning over the alloy ingot, continuously smelting for 80-100 s by using a current of 140-160A, cooling, turning over the formed alloy ingot again, and repeatedly turning over and smelting for 5-7 times;

e. and increasing the current to 340-360A, opening a suction casting valve after 1-3 s, sucking the molten alloy into a copper mold, and taking out the molten alloy after the mold is cooled to obtain the intermetallic compound-based high-entropy alloy.

4. A method of high entropy alloy based on intermetallic compounds as claimed in claim 3, characterized in that:

in the step b, the copper block, the nickel block, the cobalt block, the iron block, the titanium block, the zirconium block and the hafnium block are sequentially placed in the smelting pool I from bottom to top according to the melting point from low to high.

5. A method of high entropy alloy based on intermetallic compounds as claimed in claim 3, characterized in that:

the method for adjusting the vacuum degree in the step c comprises the steps of firstly turning on a mechanical pump to vacuumize the electric arc furnace bodyWhen the air pressure in the furnace body is reduced to 1 x 10^-1～3×10^-1When Pa, the diffusion pump is turned on again to make the vacuum degree in the furnace body reach 5X 10^-3～7×10^-3Pa。

6. A method of high entropy alloy based on intermetallic compounds as claimed in claim 3, characterized in that:

before the step d, residual oxygen in the furnace body needs to be removed, the method for removing the residual oxygen comprises the steps of putting a high-purity titanium ingot into a smelting pool II of the water-cooled copper mold, vacuumizing the furnace body, moving an electrode to the position above the smelting pool II containing the high-purity titanium ingot, conducting arc striking by using an electric arc of 50A, continuously smelting the high-purity titanium ingot by using a current of 140-160A for 80-100 s, and repeating the steps once to remove the residual oxygen in the furnace body.

7. A method according to claim 3, wherein the yield strength of the intermetallic compound based high entropy alloy is 1.60-1.70 GPa.

8. A method according to claim 3, wherein the compressive strength of the intermetallic compound based high entropy alloy is 2.50-2.55 GPa.

9. A method according to claim 3, wherein the hardness of the intermetallic compound based high entropy alloy is up to 590-600 HV.

Technical Field

The invention particularly relates to the field of high-entropy alloys, and particularly relates to a high-entropy alloy based on intermetallic compounds and a preparation method thereof.

Background

The invention belongs to the technical field of alloy materials, and discloses a single-phase TiZrHfFe based intermetallic compound_0.75Co_0.75Ni_0.75Cu_0.75Design of high-entropy alloy and preparation method thereof. The alloy takes a B2 intermetallic compound in a CoHf form as a matrix, and other atoms are dissolved in the matrix in a solid solution mode, so that the alloy has the advantages of high strength, high hardness and high-temperature stability of the intermetallic compound of the high-entropy alloy, and has wide application prospects in engineering. TiZrHfFe prepared by the invention_0.75Co_0.75Ni_0.75Cu_0.75The high-entropy alloy has excellent mechanical properties, the yield strength is 1.65Gpa, the compressive strength is 2.52Gpa, and the hardness reaches 596 HV. After 873-1473K annealing treatment for 2 hours, the phase structure of the high-entropy alloy is not changed, and the yield strength and the hardness are increased to different degrees, which proves that the alloy has excellent high-temperature stability.

Since the concept of high-entropy alloys was first mentioned in the 90s of the 20 th century, a large number of researchers have conducted extensive studies on the novel alloys. The high-entropy alloy breaks through the traditional alloy design concept, is composed of five or more elements with nearly equal atomic ratio, and has no solute and solvent between the elements. Since high-entropy alloys have very high mixing entropy and often tend to form face-centered cubic or body-centered cubic solid solutions, research has been initially focused on solid solution-based high-entropy alloys, and such high-entropy alloys have been found to have room-temperature mechanical properties, such as high strength, high hardness, high plasticity, corrosion resistance, and the like, which are superior to those of conventional alloys. With the progress of research, the strengthening phase precipitated in the high-entropy alloy is found to be capable of remarkably increasing the strength and the creep resistance of the alloy. Later, the original high-entropy alloy system is not enough to meet the application in the high-temperature field, and the refractory high-entropy alloy is produced at the same time. Refractory elements such as Ti, Zr, Hf and the like are added into a high-entropy alloy system, so that the high-temperature softening resistance and the irradiation resistance of the alloy can be greatly improved. Until recently, eutectic high-entropy alloys, which are a combination of solid solutions and ordered intermetallic compounds, were developed, again bringing the properties of high-entropy alloys to a new height.

Meanwhile, it is known that intermetallic compounds generally have the advantages of high melting point, corrosion resistance, oxidation resistance, low density and the like due to the existence of compact metallic bonds and ordered structures, such as NiAl and TiAl. In addition, a large number of ordered B2 intermetallic compounds such as CoZr, CoHf, FeTi, CoTi and NiTi, etc. have been studied intensively, among which FeTi, CoTi and CoZr have a wide prospect in hydrogen storage material applications, and NiTi can be used as a shape memory alloy.

If the advantages of the high-entropy alloy and the intermetallic compound can be combined, the mechanical property and the high-temperature property of the alloy can be greatly improved, and the problems in industrial production can be solved. Therefore, we propose a new concept, namely a high-entropy alloy based on intermetallic compounds.

Disclosure of Invention

An object of the present invention is to provide an intermetallic compound-based high entropy alloy having a single phase B2 crystal structure, high thermal stability, good yield strength, compressive strength and high hardness.

It is a further object of the present invention to provide a method for preparing an intermetallic based high entropy alloy having a single phase B2 crystal structure, high thermal stability, good yield strength, compressive strength and high hardness.

In order to achieve the above object, the present invention provides an intermetallic compound-based high entropy alloy, which is composed of the following atomic percentages:

0.9 to 1.1 parts of titanium;

0.9-1.1% of zirconium;

0.9 to 1.1 parts of hafnium;

0.7-0.8% of iron;

0.7-0.8% of cobalt;

0.7-0.8% of nickel;

0.7 to 0.8 of copper;

wherein, the molar ratio of titanium, zirconium and hafnium elements is equal, and the molar ratio of iron, cobalt, nickel and copper elements is equal.

Preferably, the alloy consists of titanium zirconium hafnium iron cobalt nickel copper 1:1:1:0.75:0.75:0.75:0.75 molar ratio.

A method for preparing the intermetallic compound-based high entropy alloy of any one of the above claims, comprising the steps of:

a. weighing a titanium block, a zirconium block, a hafnium block, an iron block, a cobalt block, a nickel block and a copper block according to a molar ratio of titanium, zirconium, hafnium, iron, cobalt, nickel and copper of 0.9-1.1: 0.7-0.8; wherein, the molar ratio of titanium, zirconium and hafnium elements is equal, and the molar ratio of iron, cobalt, nickel and copper elements is equal;

b. putting the weighed copper block, nickel block, cobalt block, iron block, titanium block, zirconium block and hafnium block into a smelting pool I of a water-cooled copper mould of an electric arc furnace;

c. vacuumizing the electric arc furnace, and adjusting the vacuum degree in the furnace body to 5 x 10^-3～7×10^-3Pa, filling argon gas with one atmosphere into the furnace body, then discharging the argon gas, and adjusting the vacuum degree in the furnace body to 5 x 10^-3～7×10^-3Pa, filling argon gas with one atmosphere into the furnace body again;

d. moving the electrode above the smelting pool I, striking an arc by using a current of 50A, continuing the current of 140-160A for 80-100 s, cooling to form an alloy ingot, turning over the alloy ingot, continuing the current of 140-160A for 80-100 s, cooling, turning over the formed alloy ingot again, and repeatedly turning over and smelting for 5-7 times;

e. and increasing the current to 340-360A, opening a suction casting valve after 1-3 s, sucking the molten alloy into a copper mold, and taking out the molten alloy after the mold is cooled to obtain the intermetallic compound-based high-entropy alloy.

Preferably, in the step b, the copper block, the nickel block, the cobalt block, the iron block, the titanium block, the zirconium block and the hafnium block are placed in the smelting pool I from bottom to top in sequence according to the melting points from low to high.

Preferably, the degree of vacuum is adjusted in step c by first turning on the machineThe pump vacuumizes the body of the electric arc furnace, and when the pressure in the body is reduced to 1 × 10^-1～3×10^-1When Pa, the diffusion pump is turned on again to make the vacuum degree in the furnace body reach 5X 10^-3～7×10^-3Pa。

Preferably, before the step d, residual oxygen in the furnace body needs to be removed, wherein the residual oxygen is removed by placing a high-purity titanium ingot into a smelting pool II of the water-cooled copper mold, vacuumizing the furnace body, moving an electrode to the position above the smelting pool II containing the high-purity titanium ingot, arc striking by using an electric arc of 50A, smelting the high-purity titanium ingot by using a current of 140-160A for 80-100 s, and repeating the steps once to remove the residual oxygen in the furnace body.

Preferably, the yield strength of the intermetallic compound-based high entropy alloy is 1.60 to 1.70 Gpa.

Preferably, the compressive strength of the intermetallic compound based high entropy alloy is 2.50 to 2.55 Gpa.

Preferably, the hardness of the intermetallic compound-based high-entropy alloy is 590 to 600 HV.

The invention has the advantages of single-phase B2 crystal structure, high thermal stability, good yield strength, compressive strength and high hardness.

Drawings

FIG. 1 is an XRD pattern of an intermetallic compound based high entropy alloy prepared in example 1.

FIG. 2 is an annealing XRD pattern of the intermetallic compound based high entropy alloy prepared in example 1.

FIG. 3 is a TEM image I of the intermetallic compound-based high-entropy alloy prepared in example 1.

FIG. 4 is a TEM image II of the intermetallic compound-based high-entropy alloy prepared in example 1

FIG. 5 is a TEM image III of the intermetallic compound-based high-entropy alloy prepared in example 1.

FIG. 6 is a graph of the compressive stress strain of the intermetallic compound based high entropy alloy prepared in example 1.

Detailed Description

The present invention is further described in detail with reference to specific examples, so that those skilled in the art can implement the invention with reference to the description.