CN111945034A - A kind of BCC structure high entropy alloy containing boron element and preparation method thereof - Google Patents

Abstract

The invention discloses a BCC structure high-entropy alloy containing boron element, which belongs to the field of high-entropy alloy materials. Its components are: aluminum: 5-15%; zirconium: 40-60%; niobium: 20 ～30%; molybdenum: 5～15%; vanadium: 0.1～5%, the balance is boron element (0.01～3.0%) and inevitable impurities; for the current typical BCC structure refractory high entropy alloys such as TaNbMoW, TaNbMoWV, etc. It contains a large amount of high-density metal elements, the alloy density is high, the cost is high, the room temperature plasticity is poor, and it is difficult to be used as a bottleneck in the application of structural materials. The present invention provides a new BCC structure refractory high-entropy alloy containing boron element and a preparation method thereof. A refractory high-entropy alloy with a BCC structure with both strength and toughness was obtained; the mixing enthalpies of boron and Mo, Nb, and Zr were ‑34, ‑54 and ‑71 kJ/mol, respectively. The polymer forms borides, and the formation of borides can strengthen the alloy through the Orowan mechanism and improve the strength of the alloy.

Description

A kind of BCC structure high entropy alloy containing boron element and preparation method thereof

technical field

The invention belongs to the field of high-entropy alloy materials, in particular to a novel high-entropy alloy containing boron element and a preparation method thereof.

Background technique

High-entropy alloy is a new type of alloy material developed in recent decades. Its concept was first proposed by Yeh et al. in 2004. It is generally obtained by mixing and smelting 4-13 different alloying elements, and each element generally accounts for about 5%-35%. . High-entropy alloys, also known as multi-component solid solution alloys, have a microstructure similar to that of liquid or amorphous atoms with random disordered arrangement. However, the multi-component mixing of high-entropy alloys forms a high mixing entropy (△Smix), making it a thermodynamically stable phase (△G<0), which is the biggest difference between high-entropy alloys and amorphous alloys, that is, multi-component alloys. The high-entropy effect of element formation leads to the stability of the phase structure at high temperature. Because the composition and structure are different from conventional alloys, high-entropy alloys have four properties that conventional alloys do not have, namely, high-entropy effect in thermodynamics, lattice distortion characteristics in structure, hysteresis effect in diffusion and cocktail effect in performance. These four properties endow high-entropy alloys with novel microstructures and easily tunable performance characteristics of multiple components, which have attracted much attention. Current research has found that high-entropy alloys may have better radiation resistance, corrosion resistance, mechanical properties and phase structure stability than conventional alloys. At present, this field has attracted the attention of scientists from the United States, Japan and other countries, and some important progress has been made. Research, as well as Nagase's research on in-situ electron irradiation at Osaka University, Japan, etc.

The density of boron (B) element is low, and its addition to high-entropy alloys can significantly reduce the density level of the alloy. At the same time, as a non-metallic element, boron is easy to combine with other elements to form a second phase. For example, the mixing enthalpy of B element with Co, Cr, Fe, Ni is -24, -31, -26 and -24 kJ/ mol, a very high absolute value of negative mixing enthalpy causes the elements to segregate to form borides, and the formation of borides will increase the strength of the alloy. In addition, the addition of B element will play a role in grain refinement of the material, so that the yield strength and plasticity level of the high-entropy alloy can be improved at the same time. However, most of the previous studies focused on alloy systems such as FeCoNiCrMn with FCC structure, and the application of refractory high-entropy alloys with BCC structure was rarely reported. Therefore, the development of a new BCC-structured refractory high-entropy alloy containing boron is of great significance for the development and application of high-performance alloy materials.

SUMMARY OF THE INVENTION

In view of the current typical BCC structure refractory high-entropy alloys such as TaNbMoW, TaNbMoWV, etc., which contain a large amount of high-density metal elements, the alloys have high density, high cost, poor room temperature plasticity, and are difficult to be used as structural materials. The bottleneck problem, the present invention proposes a boron-containing element The novel BCC structure refractory high-entropy alloy and its preparation method are prepared, and a BCC structure refractory high-entropy alloy with both strength and toughness is prepared.

The new BCC structure refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element of the present invention has the following components by mass percentage: aluminum: 5-15%; zirconium: 40-60%; niobium: 20-20% 30%; molybdenum: 5-15%; vanadium: 0.1-5%, the balance is boron element (0.01-3.0%) and inevitable impurities.

For further optimization and improvement, the above alloy components are: aluminum: 5-7%; zirconium: 40-50%; niobium: 20-30%; molybdenum: 5-10%; vanadium: 0.1-2.8% , the remainder is boron element (0.01-0.2%) and inevitable impurities.

For further optimization and improvement, the above alloy components are: aluminum: 7%; zirconium: 50%; niobium: 30%; molybdenum: 10%; vanadium: 2.8%, and the balance is boron (0.2%) and inevitable impurities.

Further optimization and improvement, the above-mentioned alloy components are: aluminum: 5-15%; zirconium: 40-60%; niobium: 20-30%; molybdenum: 5-14.89%; vanadium: 0.1-5% , the remainder is boron element (0.01-3.0 %) and inevitable impurities.

For further optimization and improvement, the above alloy components are: aluminum: 5%; zirconium: 60%; niobium: 20%; molybdenum: 14.89%; vanadium: 0.1%, and the balance is boron (0.01%) and inevitable impurities.

For further optimization and improvement, the above alloy components are: aluminum: 5-15%; zirconium: 40-60%; niobium: 20-22%; molybdenum: 5-15%; vanadium: 0.1-5% , the remainder is boron element (0.01-3.0 %) and inevitable impurities.

For further optimization and improvement, the above alloy components are: aluminum: 15%; zirconium: 40%; niobium: 22%; molybdenum: 15%; vanadium: 5%, and the balance is boron (3.0%) and inevitable impurities.

For further optimization and improvement, the above alloy components are: aluminum: 5-10%; zirconium: 40-52%; niobium: 20-30%; molybdenum: 5-15%; vanadium: 0.1-1.5% , the remainder is boron element (0.01-1.5 %) and inevitable impurities.

For further optimization and improvement, the above alloy components are: aluminum: 5-10%; zirconium: 40-52%; niobium: 20-30%; molybdenum: 5-15%; vanadium: 0.1-2.0% , the remainder is boron element (0.01-1.0 %) and inevitable impurities.

The new BCC structure refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element has a compressive yield strength: 960-1440 MPa, and an elongation: 3%-35%.

The preparation method of the novel BCC structure refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element of the present invention specifically comprises the following steps:

(1) Preparation of raw materials: Weigh the required alloy raw materials according to the ratio of the refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element;

(2) Arc smelting: under the protection of protective gas, the Al, Zr, Nb, Mo, V, B powders are rapidly heated and melted, and the powders are covered with Al foil in order to prevent the B powder from being blown away during the vacuuming process; In order to obtain alloy ingots with uniform composition, all samples were repeatedly smelted five times, and the samples were turned over after each smelting. In order to avoid smelting time, smelting current differences, etc., which may have a certain impact on the structure and properties of the sample, each sample should be smelted for 1 min after all alloying elements are completely melted into a liquid state. Turn off the current. Ensure that the surface of all samples after melting remains bright, that is, the alloy has not undergone significant oxidation during the melting preparation.

Beneficial effects:

The refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element proposed by the present invention is a new type of high-entropy alloy containing a trace amount of boron element with both strength and toughness; the addition of boron element significantly improves the performance of the new high-entropy alloy. strength and plasticity. First, boron element has the effect of grain refinement, which can refine the initial state organization and make the initial state organization more uniform. Secondly, the mixing enthalpies of boron and Mo, Nb, and Zr are -34, -54 and -71 kJ/mol, respectively. The extremely high negative mixing enthalpy causes the elements to segregate to form borides, which can be formed by Orowan. The mechanism strengthens the alloy and increases the strength of the alloy.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

On the contrary, the present invention covers any alternatives, modifications, equivalents and arrangements within the spirit and scope of the present invention as defined by the appended claims. Further, in order to give the public a better understanding of the present invention, some specific details are described in detail in the following detailed description of the present invention. The present invention can be fully understood by those skilled in the art without the description of these detailed parts. The present invention will be further described below in conjunction with specific embodiments.

Example 1

A refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron, the specific alloy composition is: 7 at.% Al, 50% Zr, 30% Nb, 10% Mo, 2.8% V, 0.2% B, The rest are unavoidable impurity elements.

The preparation method of the boron-containing refractory high-entropy Al-Zr-Nb-Mo-V-B alloy of the present embodiment is:

(1) Preparation of raw materials: Weigh the required alloy raw materials according to the ratio of the refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element. The specific alloy composition is: 7 at.% Al, 50% Zr, 30 % Nb, 10% Mo, 2.8% V, 0.2% B;

(2) Arc smelting: Under the protection of protective gas, Al, Zr, Nb, Mo, V, B powders are rapidly heated and melted; in order to obtain alloy ingots with uniform composition, all samples are repeatedly smelted five times. The samples were turned over. In order to avoid smelting time, smelting current differences, etc., which may have a certain impact on the structure and properties of the sample, each sample should be smelted for 1 min after all alloying elements are completely melted into a liquid state. Turn off the current.

The mechanical property test of the boron-containing refractory high-entropy Al-Zr-Nb-Mo-V-B alloy ingot prepared in this example shows that the compressive yield strength is 1070 MPa, and the plasticity is ~35%, showing good performance. Strength and plasticity matching properties.

Example 2

Refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element, the specific alloy composition is: 5 at.% Al, 60% Zr, 20% Nb, 14.89% Mo, 0.1% V, 0.01% B, The rest are unavoidable impurity elements.

The preparation method of the boron-containing refractory high-entropy Al-Zr-Nb-Mo-V-B alloy of the present embodiment is:

(1) Preparation of raw materials: Weigh the required alloy raw materials according to the ratio of the refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element. The specific alloy composition is: 5 at.% Al, 60% Zr, 20 % Nb, 14.89% Mo, 0.1% V, 0.01% B;

(2) Arc smelting: Under the protection of protective gas, Al, Zr, Nb, Mo, V, B powders are rapidly heated and melted; in order to obtain alloy ingots with uniform composition, all samples are repeatedly smelted five times. The samples were turned over. In order to avoid smelting time, smelting current differences, etc., which may have a certain impact on the structure and properties of the sample, each sample should be smelted for 1 min after all alloying elements are completely melted into a liquid state. Turn off the current.

The mechanical property test of the boron-containing refractory high-entropy Al-Zr-Nb-Mo-V-B alloy ingot prepared in this example shows that the compressive yield strength is 960 MPa, and the plasticity is ~17%.

Example 3

Refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element, the specific alloy composition is: 15 at.% Al, 40% Zr, 22% Nb, 15% Mo, 5% V, 3% B, The rest are unavoidable impurity elements.

The preparation method of the boron-containing refractory high-entropy Al-Zr-Nb-Mo-V-B alloy of the present embodiment is:

(1) Preparation of raw materials: Weigh the required alloy raw materials according to the ratio of the refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element. The specific alloy composition is: 15 at.% Al, 40% Zr, 22 % Nb, 15% Mo, 5% V, 3% B;

(2) Arc smelting: Under the protection of protective gas, Al, Zr, Nb, Mo, V, B powders are rapidly heated and melted; in order to obtain alloy ingots with uniform composition, all samples are repeatedly smelted five times. The samples were turned over. In order to avoid smelting time, smelting current differences, etc., which may have a certain impact on the structure and properties of the sample, each sample should be smelted for 1 min after all alloying elements are completely melted into a liquid state. Turn off the current.

The mechanical properties test of the boron-containing refractory high-entropy Al-Zr-Nb-Mo-V-B alloy ingot prepared in this example shows that the compressive yield strength is 1440 MPa, and the plasticity is ~ 2%, showing a very high the yield strength level.

Example 4

Refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element, the specific alloy composition is: 10 at.% Al, 52% Zr, 30% Nb, 5% Mo, 1.5% V, 1.5% B, The rest are unavoidable impurity elements.

The preparation method of the boron-containing refractory high-entropy Al-Zr-Nb-Mo-V-B alloy of the present embodiment is:

(1) Preparation of raw materials: Weigh the required alloy raw materials according to the ratio of the refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element. The specific alloy composition is: 10 at.% Al, 52% Zr, 30 % Nb, 5% Mo, 1.5% V, 1.5% B;

(2) Arc smelting: Under the protection of protective gas, Al, Zr, Nb, Mo, V, B powders are rapidly heated and melted; in order to obtain alloy ingots with uniform composition, all samples are repeatedly smelted five times. The samples were turned over. In order to avoid smelting time, smelting current differences, etc., which may have a certain impact on the structure and properties of the sample, each sample should be smelted for 1 min after all alloying elements are completely melted into a liquid state. Turn off the current.

The mechanical properties test of the boron-containing refractory high-entropy Al-Zr-Nb-Mo-V-B alloy ingot prepared in this example shows that the compressive yield strength is 1130 MPa, and the plasticity is ~ 21%, showing a very high the yield strength level.

Example 5

A refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron, the specific alloy composition is: 10 at.% Al, 52% Zr, 20% Nb, 15% Mo, 2% V, 1.0% B, The rest are unavoidable impurity elements.

The preparation method of the boron-containing refractory high-entropy Al-Zr-Nb-Mo-V-B alloy of the present embodiment is:

(1) Preparation of raw materials: Weigh the required alloy raw materials according to the ratio of the refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element. The specific alloy composition is: 10 at.% Al, 52% Zr, 20 % Nb, 15% Mo, 2% V, 1.0% B;

(2) Arc smelting: Under the protection of protective gas, Al, Zr, Nb, Mo, V, B powders are rapidly heated and melted; in order to obtain alloy ingots with uniform composition, all samples are repeatedly smelted five times. The samples were turned over. In order to avoid smelting time, smelting current differences, etc., which may have a certain impact on the structure and properties of the sample, each sample should be smelted for 1 min after all alloying elements are completely melted into a liquid state. Turn off the current.

The mechanical property test of the boron-containing refractory high-entropy Al-Zr-Nb-Mo-V-B alloy ingot prepared in this example shows that the compressive yield strength is 1260 MPa, and the plasticity is ~ 23%, showing a very high the yield strength level.

A novel boron-containing BCC structure refractory high-entropy Al-Zr-Nb-Mo-V-B alloy and a preparation method thereof provided by the present invention have the following advantages over existing materials:

1. Under the alloying condition of trace boron element, the yield strength of refractory high-entropy Al-Zr-Nb-Mo-V-B alloy is increased from 960 MPa of 0.01B content alloy to the highest ~ 1440 MPa, and the increase range is ~ 50%;

2. Al7-Zr50-Nb30-Mo10-V2.8-B0.2 as-cast high-entropy alloys exhibit excellent matching properties of strength and plasticity under the alloying condition of trace boron element (~ 0.2 at.%), compression Yield strength: 1070 MPa, plasticity: ~35%, better than most of the refractory high-entropy alloys currently developed;

3. Al10-Zr52-Nb20-Mo15-V2.0-B1.0 and Al10-Zr52-Nb30-Mo5-V1.5-B1.5 under the condition of low alloying of boron element (1.0~1.5 at.%) The as-cast high-entropy alloys all show higher strength and excellent plasticity level, compressive yield strength: 1130~1260 MPa, plasticity: 21~23%, and have great engineering application value.

Claims (10)

1. a BCC structure high-entropy alloy containing boron element, it is characterized in that: component is by mass percentage: aluminum: 5～15%; Zirconium: 40～60%; Niobium: 20～30%; Molybdenum: 5～15% 15%; vanadium: 0.1-5%, the balance is boron element (0.01-3.0%) and inevitable impurities. 2. a kind of BCC structure high-entropy alloy containing boron element according to claim 1, is characterized in that, the component is by mass percentage: aluminum: 5～7%; Zirconium: 40～50%; Niobium: 20～7% 30%; molybdenum: 5-10%; vanadium: 0.1-2.8%, the balance is boron element (0.01-0.2%) and inevitable impurities. 3. a kind of BCC structure high entropy alloy containing boron element according to claim 2, is characterized in that, component is by mass percentage: aluminum: 7%; Zirconium: 50%; Niobium: 30%; Molybdenum: 10% %; vanadium: 2.8%, the balance is boron element (0.2%) and inevitable impurities. 4. a kind of BCC structure high entropy alloy containing boron element according to claim 1, is characterized in that, the component is by mass percentage: aluminum: 5～15%; Zirconium: 40～60%; Niobium: 20～15% 30%; molybdenum: 5-14.89%; vanadium: 0.1-5%, the balance is boron element (0.01-3.0%) and inevitable impurities. 5. a kind of BCC structure high-entropy alloy containing boron element according to claim 4, is characterized in that, component is by mass percentage: aluminum: 5%; Zirconium: 60%; Niobium: 20%; Molybdenum: 14.89 %; vanadium: 0.1%, the balance is boron element (0.01%) and inevitable impurities. 6. a kind of BCC structure high entropy alloy containing boron element according to claim 1, is characterized in that, the component is by mass percentage: aluminum: 5～15%; Zirconium: 40～60%; Niobium: 20～15% 22%; molybdenum: 5-15%; vanadium: 0.1-5%, the balance is boron element (0.01-3.0%) and inevitable impurities. 7. a kind of BCC structure high entropy alloy containing boron element according to claim 6, is characterized in that, component is by mass percentage: aluminum: 15%; Zirconium: 40%; Niobium: 22%; Molybdenum: 15% %; vanadium: 5%, the balance is boron element (3.0%) and inevitable impurities. 8 . The BCC structure high-entropy alloy containing boron element according to claim 1 , wherein the components by mass percentage are: aluminum: 5～10%; zirconium: 40～52%; niobium: 20～10% 30%; molybdenum: 5-15%; vanadium: 0.1-1.5%, the balance is boron element (0.01-1.5%) and inevitable impurities. 9. A kind of BCC structure high entropy alloy containing boron element according to claim 1, it is characterized in that, the component by mass percentage is: aluminum: 5～10%; zirconium: 40～52%; niobium: 20～10% 30%; molybdenum: 5-15%; vanadium: 0.1-2.0%, the balance is boron element (0.01-1.0%) and inevitable impurities. 10. the method for producing the BCC structure high-entropy alloy of a kind of boron-containing element described in any one of claim 1-9, its step is: (1) Preparation of raw materials: Weigh the required alloy raw materials according to the ratio of the refractory high-entropy Al-Zr-Nb-Mo-V-B alloy containing boron element; (2) Arc smelting: Under the protection of protective gas, the Al, Zr, Nb, Mo, V, B powders are rapidly heated and melted. In order to prevent the B powders from being blown away during the vacuuming process, the powders are covered with Al foil; in order to obtain an alloy with uniform composition For ingot casting, all samples are smelted five times repeatedly, and the samples are turned over after each smelting; in order to avoid the influence on the structure and properties of the samples caused by the differences in smelting time and smelting current, each sample is smelted in each pass. After all the alloying elements were completely melted into liquid state, the current was directly turned off after smelting for 1 min; to ensure that the surface of all samples after smelting remained bright, that is, the alloy did not undergo obvious oxidation during the smelting preparation process.