阅读说明：本技术 高通量筛选用Ta-W-Nb-Al-Cr-Ti-Si系高熵合金渗镀层及其制备方法 (Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy infiltration coating for high-flux screening and preparation method thereof ) 是由 陈小虎 杨阳 王群 赵枢明 付玉 朱秀荣 任政 徐永东 聂景江 于 2020-07-13 设计创作，主要内容包括：本发明涉及一种高通量筛选用Ta-W-Nb-Al-Cr-Ti-Si系高熵合金渗镀层,其特征在于,成分表达式为：(Ta<Sub>a</Sub>W<Sub>b</Sub>Nb<Sub>c</Sub>)<Sub>x</Sub>(Al<Sub>d</Sub>Cr<Sub>e</Sub>Ti<Sub>f</Sub>Si<Sub>g</Sub>)<Sub>100-x</Sub>,其中,6<x<100；a、b和c的取值满足Ta、W、Nb中任意两种元素的物质的量之差不超过各元素总物质的量的2％；d、e、f和g的取值满足Al、Cr、Ti、Si中任意两种元素的物质的量之差不超过各元素总物质的量的1％。本发明的渗镀层具有耐高温软化、低的扩散系数,非常适合用于高温防护涂层。(The invention relates to a Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating for high-flux screening, which is characterized by comprising the following components in an expression formula: (Ta) a W b Nb c ) x (Al d Cr e Ti f Si g ) 100‑x Wherein 6 is<x<100, respectively; a. the values of b and c are such that the difference between the mass amounts of any two elements of Ta, W and Nb is not more than 2% of the total mass amount of each element; d. e, f and g are chosen such that the difference between the amounts of any two elements of Al, Cr, Ti and Si does not exceed the respective element1% of the total mass. The diffusion coating has high temperature resistance and softening resistance and low diffusion coefficient, and is very suitable for high-temperature protective coatings.)

1. A Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating for high-flux screening is characterized by comprising the following components in an expression formula: (Ta)_aW_bNb_c)x(Al_dCr_eTi_fSi_g)100-x, wherein, 6<x<100, respectively; a. the values of b and c are such that the difference between the mass amounts of any two elements of Ta, W and Nb is not more than 2% of the total mass amount of Ta, W and Nb; d. the values of e, f and g satisfy any two of Al, Cr, Ti and SiThe difference between the amounts of species of the seed elements does not exceed 1% of the total amount of Al, Cr, Ti, Si.

2. The high throughput screening Ta-W-Nb-Al-Cr-Ti-Si series high entropy alloy diffusion coating according to claim 1, characterized in that: the diffusion coating consists of a surface deposition layer and a diffusion layer; the thickness of the surface deposition layer is 10-15 mu m, and the thickness of the diffusion layer is 5-10 mu m.

3. The high throughput screening Ta-W-Nb-Al-Cr-Ti-Si series high entropy alloy diffusion coating according to claim 1, characterized in that: the horizontal plane direction of the diffusion coating is transversely provided with the same components, and the atomic percentage content of longitudinal Ta, W and Nb in the horizontal plane direction is in gradient change; the distribution of the components of Ta, W, Nb, Al, Cr, Ti and Si at the interface part of the diffusion coating layer in the direction vertical to the horizontal plane is changed in a gradient way.

4. The high throughput screening Ta-W-Nb-Al-Cr-Ti-Si series high entropy alloy diffusion coating according to claim 3, characterized in that: the component gradient change rate of Ta, W and Nb within the range of +/-4 cm of the central position of the substrate is 2-3%. cm^-1The gradient change rate of the components of Al, Cr, Ti and Si in the range is 1-2%. cm^-1。

5. The preparation method of the Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy infiltration coating for high-throughput screening according to any one of claims 1 to 4 is characterized by comprising the following steps:

1) providing a target material according to composition;

2) mounting the target material obtained in the step 1) on a target position of the arc glow plasma diffusion plating equipment, fixing a metal matrix on a sample platform of the arc glow plasma diffusion plating equipment, and then performing co-diffusion plating.

6. The method for preparing the Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating for high throughput screening according to claim 5, is characterized in that: the target material in the step 1) is a TaWNb alloy target and an AlCrTiSi alloy target.

7. The method for preparing the Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating for high throughput screening according to claim 5, is characterized in that: the target material in the step 1) is a grid target combined by a TaWNb alloy target, a TiAl target, a Cr target and a Si target; or a grid target of a combination of an AlCrTiSi alloy target, a Ta target, a W target, and a Nb target.

8. The method for preparing the Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating for high throughput screening according to claim 6, is characterized in that: and in the step 2), the TaWNb alloy target and the AlCrTiSi alloy target are arranged in parallel or at an included angle of 120 degrees when being installed at the target position.

9. The method for preparing the Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating for high throughput screening according to claim 6, is characterized in that: in the step 2), the working voltage of the TaWNb alloy target is 700-750V, the working voltage of the AlCrTiSi alloy target is 800-900V, the working voltage of the substrate is 400-450V, the vertical distance between the centers of the AlCrTiSi alloy target and the TaWNb alloy target is 8-15 cm, the distance between the centers of the AlCrTiSi alloy target and the TaWNb alloy target and the substrate is 8-10 mm, the argon pressure in the preparation process is 25-45 Pa, the working time is 5-8 h, and the treatment temperature is 700-1000 ℃.

Technical Field

The invention belongs to the technical field of metal materials, and particularly relates to a Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy infiltration coating for high-flux screening and a preparation method thereof.

Background

High entropy alloys are an emerging material that has received attention in recent years. Due to the thermodynamic high-entropy effect, the crystallographic lattice distortion effect, the dynamic slow diffusion effect and the property cocktail effect, the high-entropy alloy has the characteristics of high hardness, thermal stability, corrosion resistance, oxidation resistance and the like. At present, the high-entropy alloy is a new research hotspot and can be used as a new direction for performance breakthrough in the field of traditional thermal protection coating materials.

The multielement alloy coating prepared by adopting the plasma spraying and magnetron sputtering method can obviously improve the high-temperature oxidation resistance of the matrix. However, under thermal cycling conditions, the mismatch in thermal expansion coefficients and the oxidative deformation of the bond coat produced by such methods often cause spallation of the coating, leading to unpredictable fatigue damage and failure of the coating.

The double-layer glow plasma surface modification technology (double glow technology for short) is a surface alloying technology developed by Chinese scholars, and its principle is that under the condition of vacuum, the low-temp. plasma produced by glow discharge is used to provide plasma metal element atmosphere for metal infiltration by source electrode target made of solid metal, and the metal element to be infiltrated is transferred into the surface layer of base body to form a compact continuous gradient alloy layer with large thickness, and the alloy layer and base body are metallurgical-bound, and there is no abrupt interface, so that it has strong binding force, and does not produce large stress to initiate stripping because of large difference of expansion coefficient of base body, large internal and external temp. difference and incongruous deformation of interface. The technology can realize the preparation of the pure metal alloy layer and the multi-element alloy layer on the surface of the material.

The multi-element alloy and the high-entropy alloy coating prepared by the dual-glow technology have the advantages of good binding force, gradient distribution of interface elements and the like, and can effectively prolong the service life of the coating under the thermal cycle condition. However, at present, only a single target with multiple components is adopted to prepare the alloy through a diffusion coating method, namely, a high-entropy alloy diffusion coating with different alloy components is prepared for multiple times by adopting the single target with multiple components through a dual-glow technology, and then a component system with the best high-temperature protection effect is obtained through performance screening. The trial and error type technical research has high cost and low efficiency, and seriously hinders the development and industrial application of the novel high-entropy alloy for the high-temperature protective material.

Therefore, the development of a high-entropy alloy satisfying the thermal protection coating material and a preparation method with reduced cost are technical problems to be solved at present.

Disclosure of Invention

The first technical problem to be solved by the invention is to provide a Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating with high temperature softening resistance and low diffusion coefficient for high-flux screening aiming at the current technical situation.

The technical scheme adopted by the invention for solving the first technical problem is as follows: a Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating for high-flux screening is characterized by comprising the following components in an expression formula: (Ta)_aW_bNb_c)_x(Al_dCr_eTi_fSi_g)_100-xWherein 6 is<x<100, respectively; a. the values of b and c are such that the difference between the mass amounts of any two elements of Ta, W and Nb is not more than 2% of the total mass amount of Ta, W and Nb; d. the values of e, f and g are such that the difference between the amounts of any two elements of Al, Cr, Ti and Si is not more than 1% of the total amount of Al, Cr, Ti and Si.

Preferably, the diffusion coating consists of a surface deposition layer and a diffusion layer; the thickness of the surface deposition layer is 10-15 mu m, and the thickness of the diffusion layer is 5-10 mu m.

Preferably, the horizontal plane direction of the diffusion coating is transversely provided with the same components, and the atomic percentage content of longitudinal Ta, W and Nb in the horizontal plane direction is in gradient change; the distribution of the components of Ta, W, Nb, Al, Cr, Ti and Si at the interface part of the diffusion coating layer in the direction vertical to the horizontal plane is changed in a gradient way.

Preferably, the Ta, W and Nb have a component gradient change rate of 2-3%. cm within + -4 cm of the central position of the substrate^-1The gradient change rate of the components of Al, Cr, Ti and Si in the range is 1-2%. cm^-1。

The second technical problem to be solved by the invention is to provide a preparation method of a Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating with low cost and high throughput for screening aiming at the current technical situation.

The technical scheme adopted by the invention for solving the second technical problem is as follows: a preparation method of Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating for high-flux screening is characterized by comprising the following steps:

1) providing a target material according to composition;

2) mounting the target material obtained in the step 1) on a target position of the arc glow plasma diffusion plating equipment, fixing a metal matrix on a sample platform of the arc glow plasma diffusion plating equipment, and then performing co-diffusion plating.

Preferably, the target material in the step 1) is a TaWNb alloy target and an AlCrTiSi alloy target.

Preferably, the target material in the step 1) is a grid target formed by combining a TaWNb alloy target, a TiAl target, a Cr target and a Si target; or a grid target of a combination of an AlCrTiSi alloy target, a Ta target, a W target, and a Nb target.

Preferably, the TaWNb alloy target and the AlCrTiSi alloy target in step 2) are arranged in parallel or at an included angle of 120 degrees when the targets are installed.

The voltage, the workpiece voltage, the relative position of the target and a substrate, the argon gas pressure, the processing time and the temperature of a multi-target material of the arc glow plasma diffusion plating equipment can greatly influence the components and the thickness of a diffusion plating layer, preferably, the working voltage of the TaWNb alloy target in the step 2) is 700-750V, the working voltage of the AlCrTiSi alloy target is 800-900V, the working voltage of the substrate is 400-450V, the vertical distance between the centers of the AlCrTiSi alloy target and the TaWNb alloy target is 8-15 cm, the distance between the centers of the AlCrTiSi alloy target and the TaWNb alloy target and the substrate is 8-10 mm, the argon gas pressure in the preparation process is 25-45 Pa, the working time is 5-8 h, and the processing temperature is 700-1000 ℃.

Compared with the prior art, the invention has the advantages that: the high-entropy alloy containing Al, Cr, Si and Ti in the diffusion coating has excellent high-temperature oxidation resistance, while the high-entropy alloy containing refractory metals W, Nb and Ta has low diffusion coefficient, good high-temperature chemical stability and high-temperature softening resistance. Therefore, the Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy is very suitable for the alloy material for the high-temperature protective coating.

Drawings

FIG. 1 is a schematic diagram showing the positions and operation of a target and a substrate sample in example 1 of the present invention;

FIG. 2 is a composition distribution diagram of a Ta-W-Nb-Al-Cr-Ti-Si series high-entropy alloy diffusion coating prepared by the high-throughput screening method in example 1 of the invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.