阅读说明：本技术 一种高塑性低中子吸收截面的难熔高熵合金材料及其制备方法 (High-plasticity low-neutron absorption cross-section refractory high-entropy alloy material and preparation method thereof ) 是由 谭军 黄瑞 李威 董权 吴璐 于 2020-12-21 设计创作，主要内容包括：本发明涉及一种高塑性低中子吸收截面的难熔高熵合金材料及其制备方法,属于高熵合金技术领域。本发明高熵合金材料为AlVTiNbZr高熵合金,其中铝元素原子百分比为5～10％,V元素原子百分比为3～15％,Ti元素原子百分比为20～40％,Nb元素原子百分比为25～35％,Zr元素原子百分比为20～35％；AlVTiNbZr高熵合金具有单相BCC结构。本发明通过真空电弧熔炼的方式得到AlVTiNbZr高熵合金,具有较高的理论熔点、低的合金密度、高的室温屈服强度和变形塑性,可以抵抗服役过程中的变形失效并在服役过程中带来充足的安全裕量。(The invention relates to a high-plasticity low-neutron absorption cross section refractory high-entropy alloy material and a preparation method thereof, belonging to the technical field of high-entropy alloys. The high-entropy alloy material is AlVTiNbZr high-entropy alloy, wherein the atomic percent of aluminum element is 5-10%, the atomic percent of V element is 3-15%, the atomic percent of Ti element is 20-40%, the atomic percent of Nb element is 25-35%, and the atomic percent of Zr element is 20-35%; the AlVTiNbZr high-entropy alloy has a single-phase BCC structure. The AlVTiNbZr high-entropy alloy is obtained by a vacuum arc melting mode, has higher theoretical melting point, low alloy density, high room-temperature yield strength and deformation plasticity, can resist deformation failure in the service process and brings sufficient safety allowance in the service process.)

1. A refractory high-entropy alloy material with high plasticity and low neutron absorption cross section is characterized in that: the material is AlVTiNbZr high-entropy alloy, wherein the atomic percent of aluminum element is 5-10%, the atomic percent of V element is 3-15%, the atomic percent of Ti element is 20-40%, the atomic percent of Nb element is 25-35%, and the atomic percent of Zr element is 20-35%; the AlVTiNbZr high-entropy alloy has a single-phase BCC structure.

2. The preparation method of the refractory high-entropy alloy material with the high plasticity and the low neutron absorption cross section, which is characterized by comprising the following specific steps:

(1) removing oxide skins on the surfaces of five raw materials of Al, V, Ti, Nb and Zr, and cleaning;

(2) sequentially adding five raw materials of Al, V, Ti, Nb and Zr into a smelting container according to the sequence of melting points from low to high;

(3) vacuumizing, introducing high-purity argon to keep a protective gas atmosphere, performing vacuum arc melting on Ti in a melting container, solidifying after the Ti is completely melted, then melting Al, V, Ti, Nb and Zr until the Ti is completely melted and uniformly mixed, cooling and solidifying to obtain a button ingot, performing turnover melting on the button ingot for more than 30s, repeatedly performing turnover melting for 3-8 times, and cooling to room temperature to obtain the high-plasticity low-neutron absorption cross-section refractory high-entropy alloy.

3. The preparation method of the refractory high-entropy alloy material with the high plasticity and the low neutron absorption cross section according to claim 2, is characterized by comprising the following steps: step (3) vacuum degree not higher than 6X 10^-2 Pa。

4. The preparation method of the refractory high-entropy alloy material with the high plasticity and the low neutron absorption cross section according to claim 2, is characterized by comprising the following steps: and (4) the current of the vacuum arc melting in the step (3) is not less than 300A.

Technical Field

The invention relates to a high-plasticity low-neutron absorption cross section refractory high-entropy alloy material and a preparation method thereof, belonging to the technical field of high-entropy alloys.

Background

The refractory high-entropy alloy is characterized in that high-melting-point elements such as Mo, Nb, Ta, W, Ti, Zr, V and the like are used wholly or partially, and the prepared alloy has good high-temperature performance. However, the alloy has the disadvantages of high density and poor room temperature plasticity while having good high temperature performance due to the mixed use or mixed addition of the above elements, and the potential use range of the alloy is limited to a certain extent, so that a refractory high-entropy alloy with low density, high yield strength and good deformation plasticity is in urgent need.

The traditional Zr alloy cladding material can generate atomic defects under the impact of irradiation particles after neutron irradiation, so that lattice distortion is caused, the lattice constant is increased, and macroscopic phenomena such as irradiation hardening, irradiation embrittlement and the like are caused, so that the material fails. In order to avoid safety accidents caused by material failure, the cladding material needs to be replaced by stopping the machine after the material is in service for a period of time, and the shutdown for replacing the cladding material causes a great economic loss. It is a challenge to scientists to extend the service life of materials and reduce the number of reactor shutdowns and reloads. In addition, most of the traditional cladding materials mainly comprise Zr alloy, metal Zr and water react to release hydrogen in a high-temperature environment, and hydrogen is gathered and exploded to bring great safety damage to workers and the surrounding environment.

Disclosure of Invention

The invention provides a high-plasticity low-neutron absorption cross-section refractory high-entropy alloy material and a preparation method thereof, aiming at the problems of high density, poor room temperature plasticity and the like of the refractory high-entropy alloy in the prior art, the invention obtains the AlVTiNbZr high-entropy alloy in a vacuum arc melting mode, has higher theoretical melting point, low alloy density, high room temperature yield strength and deformation plasticity, and can resist deformation failure in the service process and bring sufficient safety allowance; the AlVTiNbZr high-entropy alloy is of a single-phase BCC structure, has a low thermal neutron absorption coefficient, and has a higher safety coefficient compared with the traditional Zr alloy.

A refractory high-entropy alloy material with a high plasticity and a low neutron absorption cross section is an AlVTiNbZr high-entropy alloy, wherein the atomic percent of aluminum element is 5-10%, the atomic percent of V element is 3-15%, the atomic percent of Ti element is 20-40%, the atomic percent of Nb element is 25-35%, and the atomic percent of Zr element is 20-35%; the AlVTiNbZr high-entropy alloy has a single-phase BCC structure.

The preparation method of the refractory high-entropy alloy material with the high plasticity and the low neutron absorption cross section comprises the following specific steps:

(1) polishing by using sand paper or a grinding wheel machine to remove oxide skins on the surfaces of the five raw materials of Al, V, Ti, Nb and Zr, and cleaning by using ethanol; wherein Al, V, Ti, Nb and Zr are all blocks with the purity of more than 99.77 wt%;

(2) sequentially adding five raw materials of Al, V, Ti, Nb and Zr into a smelting container according to the sequence of melting points from low to high; ensuring that the low-melting-point material is positioned at the bottom of the smelting container;

(3) vacuumizing, introducing high-purity argon to keep a protective gas atmosphere, carrying out vacuum arc melting on Ti in a melting container to detect and consume trace oxygen in the furnace, solidifying after the Ti is completely melted, then smelting Al, V, Ti, Nb and Zr until the Ti is completely melted and uniformly mixed, cooling and solidifying to obtain a button ingot, carrying out turnover melting on the button ingot for more than 30s, repeatedly carrying out turnover melting for 3-8 times, and cooling to room temperature to obtain the high-plasticity low-neutron absorption cross-section refractory high-entropy alloy;

the pressure of argon in the furnace is lower than the pressure of the environment outside the furnace;

the vacuum degree of the step (3) is not higher than 6 multiplied by 10^-2Pa；

The current of the vacuum arc melting in the step (3) is not less than 300A.

The invention has the beneficial effects that:

(1) the AlVTiNbZr high-entropy alloy has higher melting point, good high-temperature mechanical property and low density, and the alloy density is 6.2-6.4 g/cm³To (c) to (d);

(2) the AlVTiNbZr high-entropy alloy has compressive yield strength of more than 1100MPa, is not broken when the compressive deformation exceeds 50 percent, and has good plasticity;

(3) the invention carries out high-entropy alloy design by using five elements of Al, V, Ti, Nb and Zr with low thermal neutron absorption cross section, thereby ensuring that the alloy has low thermal neutron absorption cross section; in addition, as a nuclear cladding material, the Zr element content in the series of alloys is low, and a sufficient safety margin is reserved in an extreme case, so that the use safety of the alloys is greatly improved.

Drawings

FIG. 1 is an XRD diffraction pattern of an alloy prepared in a series of examples;

FIG. 2 is a graph of stress-strain curves for room temperature compressive engineering of alloys prepared in a series of examples.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but the scope of the present invention is not limited to the description.

Example 1: refractory AlVTiNbZr high-entropy alloy material with high plasticity and low neutron absorption cross section, and is recorded as Nb according to atomic percentage₃₁Ti_37-xZr₂₆Al₆V_xWherein x is 3, the AlVTiNbZr high-entropy alloy has a single-phase body-centered cubic structure;

a preparation method of a refractory high-entropy alloy material with high plasticity and low neutron absorption cross section comprises the following specific steps:

(1) polishing by using sand paper or a grinding wheel machine to remove oxide skins on the surfaces of the five raw materials of Al, V, Ti, Nb and Zr, and cleaning by using ethanol; wherein Al, V, Ti, Nb and Zr are all blocks with the purity of more than 99.77 wt%;

(2) sequentially adding five raw materials of Al, V, Ti, Nb and Zr into a vacuum arc melting furnace according to the sequence of melting points from low to high; ensuring that the low-melting-point material is positioned at the bottom of the smelting container;

(3) vacuum-pumping to 6X 10^-2Introducing 99.9 wt% of high-purity argon under Pa to perform anti-oxidation protection, wherein the air pressure in the furnace is lower than the ambient air pressure outside the furnace, performing vacuum arc melting on a Ti ingot in the vacuum arc melting furnace to detect and consume trace oxygen in the furnace, after the Ti is completely melted and kept for 30s, closing an electric arc to completely cool and solidify the Ti ingot, melting Al, V, Ti, Nb and Zr until the Ti ingot is completely melted after the surface of the Ti ingot presents silvery white metallic luster, keeping the liquid state for more than 30s to uniformly mix, cooling and solidifying to obtain a button ingot, turning over the button ingot, performing vacuum arc melting for more than 30s, repeatedly turning over and melting for 6 times, stirring from the 3 rd time of melting, cooling to room temperature, and stirringObtaining an alloy ingot; sampling the alloy cast ingot, carrying out X-ray diffraction observation to obtain an X-ray diffraction spectrum of the alloy, comparing three strong peaks in the spectrum with standard PDF card data as shown in a curve V (becoming 3) in the attached drawing 1, and confirming that a solid solution with a single-phase BCC (BCC) structure is formed in the alloy; wherein the smelting current of the vacuum arc smelting furnace is 300-600A;

the density of the AlVTiNbZr high-entropy alloy of the embodiment is 6.237g/cm³The room temperature compression experiment shows that the material has a compressive yield strength of 951MPa and a compressive deformation of more than 50 percent and is not broken, which proves that the alloy has good plasticity;

the theoretical melting point of the AlVTiNbZr high-entropy alloy obtained by calculation by using a mixing rule is 1913 ℃, which is higher than the melting point of a common alloy.

Example 2: refractory AlVTiNbZr high-entropy alloy material with high plasticity and low neutron absorption cross section, and is recorded as Nb according to atomic percentage₃₁Ti_37-xZr₂₆Al₆V_xWherein x is 5, the alvtinnbzr high entropy alloy has a single phase BCC structure;

a preparation method of a refractory high-entropy alloy material with high plasticity and low neutron absorption cross section comprises the following specific steps:

(1) polishing by using sand paper or a grinding wheel machine to remove oxide skins on the surfaces of the five raw materials of Al, V, Ti, Nb and Zr, and cleaning by using ethanol; wherein Al, V, Ti, Nb and Zr are all blocks with the purity of more than 99.77 wt%;

(2) sequentially adding five raw materials of Al, V, Ti, Nb and Zr into a vacuum arc melting furnace according to the sequence of melting points from low to high; ensuring that the low-melting-point material is positioned at the bottom of the smelting container;

(3) vacuum-pumping to 6X 10^-2Introducing 99.9 wt% of high-purity argon under Pa to perform anti-oxidation protection, wherein the air pressure in the furnace is lower than the ambient air pressure outside the furnace, performing vacuum arc melting on a Ti ingot in the vacuum arc melting furnace to detect and consume trace oxygen in the furnace, closing an arc to completely cool and solidify the Ti ingot after the Ti is completely melted and kept for 30s, melting Al, V, Ti, Nb and Zr until the Ti is completely melted and kept for more than 40s after the surface of the Ti ingot presents silvery white metallic luster, uniformly mixing the Ti, the Nb and the Zr, and cooling and solidifying the mixture to obtain the knobBuckling ingots, turning over the button ingots, then carrying out vacuum arc melting for more than 40s, repeatedly turning over and melting for 7 times, stirring from the 4 th melting, and cooling to room temperature to obtain alloy ingots; sampling the alloy cast ingot, carrying out X-ray diffraction observation to obtain an X-ray diffraction spectrum of the alloy, and comparing the X-ray diffraction spectrum with standard PDF card data to confirm that a solid solution with a single-phase BCC structure is formed in the alloy as shown by a curve V (5) in the attached figure 1; wherein the smelting current of the vacuum arc smelting furnace is 300-600A;

the density of the AlVTiNbZr high-entropy alloy of the embodiment is 6.279g/cm³Through a room temperature compression experiment, the material has the compression yield strength of 1020MPa, and the alloy is not broken after the compression deformation is more than 50 percent, so that the alloy is proved to have good plasticity;

the theoretical melting point of the AlVTiNbZr high-entropy alloy obtained by calculation by using a mixing rule is 1918 ℃, which is higher than the melting point of a common alloy.

Example 3: refractory AlVTiNbZr high-entropy alloy material with high plasticity and low neutron absorption cross section, and is recorded as Nb according to atomic percentage₃₁Ti_37-xZr₂₆Al₆V_xWherein x is 7, the alvtinnbzr high entropy alloy has a single phase BCC structure;

a preparation method of a refractory high-entropy alloy material with high plasticity and low neutron absorption cross section comprises the following specific steps:

(1) polishing by using sand paper or a grinding wheel machine to remove oxide skins on the surfaces of the five raw materials of Al, V, Ti, Nb and Zr, and cleaning by using ethanol; wherein Al, V, Ti, Nb and Zr are all blocks with the purity of more than 99.77 wt%;

(2) sequentially adding five raw materials of Al, V, Ti, Nb and Zr into a vacuum arc melting furnace according to the sequence of melting points from low to high; ensuring that the low-melting-point material is positioned at the bottom of the smelting container;

(3) vacuum-pumping to 6X 10^-2Introducing 99.9 wt% of high-purity argon under Pa to perform anti-oxidation protection, wherein the pressure in the furnace is lower than the ambient pressure outside the furnace, performing vacuum arc melting on the Ti ingot in the vacuum arc melting furnace to detect and consume trace oxygen in the furnace, closing the arc to completely cool and solidify the Ti ingot after the Ti is completely melted and kept for 40s, and forming silver white gold on the surface of the Ti ingotAfter the alloy ingot is glossy, smelting Al, V, Ti, Nb and Zr until the Al, V, Ti, Nb and Zr are completely molten and are kept for more than 35s to be uniformly mixed, cooling and solidifying to obtain a button ingot, overturning the button ingot, then carrying out vacuum arc smelting for more than 35s, repeatedly overturning and smelting for 8 times, stirring from the 4 th smelting, and cooling to room temperature to obtain an alloy ingot; sampling the alloy cast ingot, carrying out X-ray diffraction observation to obtain an X-ray diffraction spectrum of the alloy, and comparing the X-ray diffraction spectrum with standard PDF card data to confirm that a solid solution with a single-phase BCC structure is formed in the alloy as shown by a curve V (7) in the attached figure 1; wherein the smelting current of the vacuum arc smelting furnace is 300-600A;

the density of the AlVTiNbZr high-entropy alloy of the embodiment is 6.307g/cm³Through a room temperature compression experiment, the material has the compression yield strength of 1084MPa, and the alloy is not broken after the compression deformation is more than 50 percent, so that the alloy is proved to have good plasticity;

the theoretical melting point of the AlVTiNbZr high-entropy alloy obtained by calculation by using a mixing rule is 1922 ℃, which is higher than the melting point of a common alloy.

Example 4: refractory AlVTiNbZr high-entropy alloy material with high plasticity and low neutron absorption cross section, and is recorded as Nb according to atomic percentage₃₁Ti_37-xZr₂₆Al₆V_xWherein x is 9, the alvtinnbzr high entropy alloy has a single phase BCC structure;

a preparation method of a refractory high-entropy alloy material with high plasticity and low neutron absorption cross section comprises the following specific steps:

(1) polishing by using sand paper or a grinding wheel machine to remove oxide skins on the surfaces of the five raw materials of Al, V, Ti, Nb and Zr, and cleaning by using ethanol; wherein Al, V, Ti, Nb and Zr are all blocks with the purity of more than 99.77 wt%;

(2) sequentially adding five raw materials of Al, V, Ti, Nb and Zr into a vacuum arc melting furnace according to the sequence of melting points from low to high; ensuring that the low-melting-point material is positioned at the bottom of the smelting container;

(3) vacuum-pumping to 6X 10^-2Introducing 99.9 wt% of high-purity argon under Pa to perform anti-oxidation protection, wherein the pressure in the furnace is lower than the ambient pressure outside the furnace, and performing vacuum arc melting on the Ti ingot in the vacuum arc melting furnace to detect and eliminateConsuming trace oxygen in the furnace, completely melting Ti and keeping for 35s, closing the electric arc to completely cool and solidify the Ti ingot, melting Al, V, Ti, Nb and Zr until the Ti ingot is completely melted and keeps more than 40s after the surface of the Ti ingot presents silvery white metallic luster, uniformly mixing the Ti ingot with the Al, V, Ti, Nb and Zr, cooling,

Solidifying to obtain a button ingot, turning over the button ingot, then carrying out vacuum arc melting for more than 30s, repeatedly turning over and melting for 7 times, carrying out electromagnetic stirring from the 3 rd time of melting, and cooling to room temperature to obtain an alloy ingot; sampling the alloy cast ingot, carrying out X-ray diffraction observation to obtain an X-ray diffraction spectrum of the alloy, and comparing the X-ray diffraction spectrum with standard PDF card data to confirm that a solid solution with a single-phase BCC structure is formed in the alloy as shown by a V-9 curve in the attached figure 1; wherein the melting current of the vacuum arc melting furnace is

300～600A；

The density of the AlVTiNbZr high-entropy alloy of the embodiment is 6.34g/cm³Through a room-temperature compression experiment, the material has the compression yield strength of 1122MPa, and the alloy is not broken after the compression deformation is more than 50%, so that the alloy is proved to have good plasticity;

the theoretical melting point of the AlVTiNbZr high-entropy alloy obtained by calculation by using a mixing rule is 1931 ℃, which is higher than the melting point of common alloys.

Example 5: refractory AlVTiNbZr high-entropy alloy material with high plasticity and low neutron absorption cross section, and is recorded as Nb according to atomic percentage₃₁Ti_37-xZr₂₆Al₆V_xWherein x is 11, the alvtinnbzr high entropy alloy has a single phase BCC structure;

a preparation method of a refractory high-entropy alloy material with high plasticity and low neutron absorption cross section comprises the following specific steps:

(1) polishing by using sand paper or a grinding wheel machine to remove oxide skins on the surfaces of the five raw materials of Al, V, Ti, Nb and Zr, and cleaning by using ethanol; wherein Al, V, Ti, Nb and Zr are all blocks with the purity of more than 99.77 wt%;

(2) sequentially adding five raw materials of Al, V, Ti, Nb and Zr into a vacuum arc melting furnace according to the sequence of melting points from low to high; ensuring that the low-melting-point material is positioned at the bottom of the smelting container;

(3) vacuum-pumping to 6X 10^-2Introducing 99.9 wt% of high-purity argon under Pa for anti-oxidation protection, wherein the air pressure in the furnace is lower than the ambient air pressure outside the furnace, carrying out vacuum arc melting on a Ti ingot in the vacuum arc melting furnace to detect and consume trace oxygen in the furnace, after the Ti is completely melted and kept for 40s, closing an electric arc to completely cool and solidify the Ti ingot, after the surface of the Ti ingot presents silvery white metallic luster, smelting Al, V, Ti, Nb and Zr until the Ti ingot is completely melted and kept for more than 35s to be uniformly mixed, cooling and solidifying to obtain a button ingot, turning over the button ingot, carrying out vacuum arc melting for more than 35s, repeatedly turning over and smelting for 6 times, carrying out electromagnetic stirring from the 3 rd time of smelting, and cooling to room temperature to obtain an alloy ingot; sampling the alloy cast ingot, carrying out X-ray diffraction observation to obtain an X-ray diffraction pattern of the alloy, and confirming that a single-phase body-centered cubic structure solid solution is formed in the alloy after comparing with standard PDF card data as shown in a curve V (11) in the attached drawing 1; wherein the smelting current of the vacuum arc smelting furnace is 300-600A;

the density of the AlVTiNbZr high-entropy alloy of the embodiment is 6.37g/cm³Through a room temperature compression experiment, the material has the compression yield strength of 1139MPa, and the material is not broken after the compression deformation is more than 50 percent, so that the alloy is proved to have good plasticity;

the theoretical melting point of the AlVTiNbZr high-entropy alloy obtained by calculation by using a mixing rule is 1932 ℃ which is higher than the melting point of common alloys;

an XRD diffraction pattern of the refractory high-entropy alloy prepared in the embodiments 1-5 is shown in figure 1, and as can be seen from figure 1, a single-phase BCC structure solid solution can be inferred to be formed in the alloy according to the positions of three strong peaks in the XRD diffraction pattern;

the stress-strain curve of the refractory high-entropy alloy prepared in the embodiment 1-5 in the room temperature compression engineering is shown in fig. 2, and as can be seen from fig. 2, in the room temperature compression experiment process, the alloy in the embodiment has high yield strength, and the yield strength of some embodiments exceeds 1 GPa; meanwhile, the material shows good ductility, still does not break when the compression deformation reaches 50%, and the yield strength and the compression strength at 50% deformation show regular changes according to different embodiments.

While the present invention has been described in detail with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, and various changes and modifications can be made within the knowledge of those skilled in the art without departing from the spirit of the present invention.