A ni-cro-al-y target material and a method of making the same

Abstract

The application belongs to the field of target materials, and particularly discloses a NiCrCoAlY target material and a preparation method thereof. The NiCrCoAlY target blank is prepared by pre-mixing NiCrCoAl alloy powder and Y metal powder and combining hot isostatic pressing and sintering. Since the powder is fine, the contact between the powders is good, and there is no pore in the inside of the target blank, the density of the target blank is high. At the same time, the hardness is high due to the fine-grain strengthening principle during sintering, and the target blank is more suitable for service conditions.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of target materials, and particularly relates to a NiCrCoAlY target material and a preparation method thereof. BACKGROUND

[0002] As a new type of alloy material, the NiCrCoAlY alloy has been widely applied to the surface of hot end parts such as gas turbine blades of aircrafts, automobiles and ships, high-pressure turbine shells, etc. as a coating material due to its good hardness, heat corrosion resistance and oxidation resistance. In the fields of aerospace, automobile and ship, and gas turbine, the surface of high-temperature parts made of high-temperature alloy is often provided with a NiCrCoAlY coating with a thickness of 50-200 microns by means of magnetron sputtering or spraying, so as to improve the heat corrosion resistance of the base material, and prolong the heat resistance life by thousands of hours or even nearly ten thousand hours.

[0003] The traditional preparation method of the NiCrCoAlY target material is vacuum melting, and the specific manufacturing process is as follows: Ni blocks, Al blocks, Cr blocks, Y blocks and Co blocks with different purities and proportions are melted and cast into ingots under vacuum conditions, and then the ingots are further machined into target blanks. The target material processed by this method has low density due to the pores in the target material, and has organization segregation phenomenon due to different temperatures in different areas during casting. In addition, the rare earth element Y has a serious evaporation phenomenon at high temperature melting (greater than 1400℃), which leads to a serious decrease of Y element in the target blank or even no Y element. Due to the above problems, the target material prepared by the traditional vacuum melting method has poor application performance. SUMMARY

[0004] In view of the problems of the prior art, such as poor density performance of the NiCrCoAlY target material, the application provides a NiCrCoAlY target material and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the technical scheme comprises the following steps:

[0006] A preparation method of a NiCrCoAlY target material, comprising the following steps:

[0007] (1) melting and casting Ni, Al, Cr and Co under vacuum to obtain a NiCrCoAl alloy ingot;

[0008] (2) crushing and grinding the NiCrCoAl alloy ingot to obtain a NiCrCoAl alloy powder;

[0009] (3) mixing the NiCrCoAl alloy powder and Y powder (yttrium metal powder), and sequentially performing cladding, molding, degassing and hot isostatic pressing sintering to obtain the NiCrCoAlY target material.

[0010] The application is a NiCrCoAlY target blank prepared by pre-mixing NiCrCoAl alloy powder and Y metal powder and hot isostatic pressing, which has better contact between powders due to the fine powder, and has no pores in the target blank, and has higher density; at the same time, the hardness is higher due to fine grain strengthening principle, and is more suitable for service conditions. In addition, through the double alloy (NiCrCoAl alloy powder and Y metal powder) method, the precise control of rare earth Y element in the target material can be realized, and the waste of rare earth Y element and the instability of the organization and composition caused by the traditional melting process can be avoided.

[0011] As a preferred embodiment of the application, in step (1), the mass percentage of Ni, Cr, Co and Al elements in the NiCrCoAl alloy ingot is: Ni 20-40%, Al 10-20%, Cr 10-20%, Co 20-40%.

[0012] As a preferred embodiment of the application, in step (1), the temperature of the melting is 1300-1800℃, and further preferably 1450-1500℃.

[0013] As a preferred embodiment of the application, in step (1), the temperature of the casting is 1300-1800℃, and further preferably 1450-1500℃.

[0014] As a preferred embodiment of the application, in step (2), the crushing includes at least one of ball milling and jet milling.

[0015] As a preferred embodiment of the application, in step (3), the mixing specifically includes the following steps: under an inert gas, the NiCrCoAl alloy powder and Y powder are ball milled in a ball-to-material mass ratio of 0.1-0.8; the inert gas includes at least one of nitrogen, argon and helium.

[0016] As a further preferred embodiment of the application, the ball milling time is 2-24h.

[0017] As a preferred embodiment of the application, in step (3), the mass percentage of the Y powder in the NiCrCoAlY target material is 0.2-4%.

[0018] As a preferred embodiment of the application, in step (3), the degassing temperature is 200-600℃; and the vacuum degree in the package after degassing is less than 5x10- 4 pa.

[0019] As a preferred embodiment of the present application, in step (3), the temperature of the hot isostatic pressing sintering is 750-1200℃, the pressure is 120-180MPa, and the holding time is 2-6h. During the heating process, the heating rate is 3-8℃ / min.

[0020] As a further preferred embodiment of the present application, in step (3), the temperature of the hot isostatic pressing sintering is 850-1000℃.

[0021] As a preferred embodiment of the present application, in step (3), the mesh number of the NiCrCoAl alloy powder is 10-300 mesh; and the mesh number of the Y powder is 50-450 mesh.

[0022] As a further preferred embodiment of the present application, in step (3), the mesh number of the NiCrCoAl alloy powder is 80-200 mesh; and the mesh number of the Y powder is 100-300 mesh.

[0023] Compared with the prior art, the present application has the following beneficial effects: the NiCrCoAlY target blank prepared by the present application through the combination of pre-mixing of NiCrCoAl alloy powder and Y metal powder and hot isostatic pressing sintering, has a higher density than the traditional vacuum melting method, because the powder is finer, the contact between the powders is better, and there are no pores in the target blank. At the same time, due to the fine-grain strengthening principle during sintering, the hardness is higher, and the target material has high hardness. As a coating, it can improve the surface strength of the parts for aerospace, automobiles, ships, and gas turbine parts for power generation, thereby prolonging the service life. In addition, through the double-alloy method, the rare earth Y element in the target material can be precisely controlled, avoiding the waste of rare earth Y element and the instability of the organization and composition in the traditional melting process. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a schematic diagram of the package structure, wherein 1 is a degassing port, 2 is graphite paper, 3 is a partition, and 4 is NiCrCoAlY powder.

[0025] Figure 2 It is a metallographic microscope grain diagram of the NiCrCoAlY target material of Example 1.

[0026] Figure 3 It is a water immersion type ultrasonic C scan test result diagram of the NiCrCoAlY target material of Example 1.

[0027] Figure 4 It is a physical diagram of the NiCrCoAlY target material of Example 1. DETAILED DESCRIPTION

[0028] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below through specific examples. The test methods used in the examples and / or comparative examples are all conventional methods unless otherwise specified; the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0029] Example 1

[0030] The present embodiment discloses a preparation method of a NiCrCoAlY target material, comprising the following steps:

[0031] (1) configuring Ni block, Al block, Cr block, Co block, all with a purity of 3N, and the mass percentage of each is 30%, 20%, 15%, and 35% respectively. Melting the above metal materials under vacuum and at 1450℃, and casting into a NiCrCoAl alloy ingot at 1500℃;

[0032] (2) crushing the NiCrCoAl alloy ingot into 1-2mm coarse powder through a jaw crusher, and then further crushing into 80-200 mesh NiCrCoAl alloy powder by ball milling;

[0033] (3) taking and uniformly mixing 80-200 mesh NiCrCoAl alloy powder and 100-300 mesh Y powder (commercially available) according to a mass ratio of 99.7:0.3. In order to fully mix the NiCrCoAl powder and Y powder uniformly and prevent oxidation, the powder mixing is carried out by ball milling for 12h in a nitrogen atmosphere, and the ball-to-material ratio is 1:4;

[0034] (4) preparing a package: the package structure is as shown in Figure 1 The package comprises a bottom plate, an outer side plate, a partition plate (3), a graphite paper (2), a cover plate and a degassing pipe (1). The bottom plate is installed at the bottom of the outer side plate, and the cover plate is installed at the top of the outer side plate. The cover plate is provided with a through hole, and the degassing pipe is installed at the through hole. The partition plate and the graphite paper are arranged in the cylindrical accommodating space formed by the bottom plate, the outer side plate and the cover plate. The thickness of the partition plate is 4-8mm, and the thickness of the graphite paper is 0.2-1mm. The outer diameter of the degassing pipe is 8-16mm, and the wall thickness of the degassing pipe is 2-6mm. The materials of the bottom plate, the outer side plate, the partition plate, the cover plate and the degassing pipe are low-carbon steel or stainless steel. The installation modes of the bottom plate and the outer side plate, the cover plate and the outer side plate, and the cover plate and the degassing pipe are all fixed by argon arc welding.

[0035] (4) Assemble the bottom plate and the outer side plate to form a half-finished product of a package with an open end. Put graphite paper on the inner wall of the outer side plate. Put graphite paper, a partition plate and graphite paper in sequence on the bottom of the half-finished product of the package. Weigh 2 kg of mixed NiCrCoAlY alloy powder with a purity of 99.9%. Put the powder into the package in 4 times. After each time of putting the powder, tamp and level the powder. After all the 2 kg of NiCrCoAlY alloy powder is put into the package and tamped, put graphite paper, an intermediate partition plate and graphite paper in sequence on the powder (4). At this time, the plane of the topmost graphite paper is basically flush with the top opening of the half-finished product of the package. Finally, fix the cover plate on the top of the half-finished product of the package with a C-shaped clamp. Weld the cover plate and the package with argon arc welding, and weld a degassing pipe on the through hole of the cover plate.

[0036] (5) Put the assembled package into a furnace and heat it to 400 ℃. Perform vacuum degassing on the package through the degassing pipe. When the vacuum degree in the package reaches less than 5 × 10- 5 pa, stop heating and degassing, and close the degassing pipe. 4 pa after, stop heating, degassing, and close the degassing pipe.

[0037] (6) Put the degassed package into a hot isostatic pressing sintering furnace to perform vacuum pumping, pressurization, temperature rising sintering, temperature falling and pressure recovery. During the temperature rising sintering process, the temperature rising rate is 6 ℃ / min, the sintering temperature is 850 ℃, the pressure is 160 MPa, and the temperature maintaining and pressure maintaining time is 4 h. After the temperature rising sintering is completed, perform temperature falling and pressure recovery. When the temperature is less than 100 ℃ and the pressure of the hot isostatic pressing sintering furnace is 0 MPa, the package reaches the standard for being taken out of the furnace.

[0038] (7) Take the package out of the furnace to remove the package, and obtain a NiCrCoAlY target material rough blank.

[0039] (8) Further machine the NiCrCoAlY target material rough blank to prepare NiCrCoAlY target materials with different sizes.

[0040] Example 2

[0041] Compared with Example 1, the difference of this example is that the temperature of the hot isostatic pressing sintering is 750 ℃.

[0042] Example 3

[0043] Compared with Example 1, the difference of this example is that the temperature of the hot isostatic pressing sintering is 1000 ℃.

[0044] Example 4

[0045] Compared with Example 1, the difference of this example is that the temperature of the hot isostatic pressing sintering is 1200 ℃.

[0046] Example 5

[0047] Compared with Example 1, the difference of this example is that the pressure of the hot isostatic pressing sintering is 120 MPa.

[0048] Example 6

[0049] The difference between this example and Example 1 is that the pressure of the hot isostatic sintering is 180 MPa.

[0050] Example 7

[0051] The difference between this example and Example 1 is that the mesh of the NiCrCoAl alloy powder is 10-60 mesh.

[0052] Example 8

[0053] The difference between this example and Example 1 is that the mesh of the NiCrCoAl alloy powder is 100-300 mesh.

[0054] Example 9

[0055] The difference between this example and Example 1 is that the mesh of the Y powder is 50-80 mesh.

[0056] Example 10

[0057] The difference between this example and Example 1 is that the mesh of the Y powder is 350-450 mesh.

[0058] Comparative Example 1

[0059] The difference between this comparative example and Example 1 is that the comparative example uses a traditional vacuum melting method: 3N purity Ni blocks, Al blocks, Cr blocks, Y blocks, Co blocks are selected, and the mass ratio is 30%, 20%, 15%, 0.3%, and 34.7%, respectively. Melting is carried out under vacuum conditions at a temperature of 1500°C, and the ingot is cast, and then further machined into a target blank.

[0060] Comparative Example 2

[0061] The difference between this comparative example and Example 1 is that the temperature of the hot isostatic sintering is 600°C.

[0062] Comparative Example 3

[0063] The difference between this comparative example and Example 1 is that the temperature of the hot isostatic sintering is 1300°C.

[0064] The density of the target material and its compactness were measured using the Archimedes method (Table 1), the Vickers hardness was tested using a Vickers hardness tester (Table 1), the grain microstructure was tested using a metallographic microscope (Table 1 and Figure 2 Figure 3 The internal shrinkage was tested using a water immersion type ultrasonic C scan (Table 1 and

[0065] Table 1 Parameters of the target materials prepared in the examples and comparative examples​

[0066] Density / g / cm 3 ]] Density Vickers hardness / HV Grain size / pm Example 1 7.23 100％ 620 6.3 Example 2 7.21 99.72％ 618 6.1 Example 3 7.23 100％ 623 6.5 Example 4 7.22 99.86 631 6.0 Example 5 7.23 100％ 625 5.8 Example 6 7.20 99.59％ 617 6.6 Example 7 7.23 100％ 618 5.9 Example 8 7.22 99.86％ 623 6.4 Example 9 7.21 99.72％ 623 6.7 Example 10 7.23 100％ 619 6.2 Comparative Example 1 6.4 88.52％ 356 14.3 Comparative Example 2 6.8 94.05％ 563 5.9 Comparative Example 3 7.21 99.72％ 582 8.9

[0067] From Table 1, it can be seen that the target blank has good density and a Vickers hardness of up to 620 HV, and the grain size is fine. Figure 2 We can see that the grain roundness is good, and the grain size range is narrow, which is more conducive to the uniformity of the macroscopic performance of the target blank. Figure 3 We can see that there are only a small amount of defects on the edge of the target blank, which can be removed by subsequent machining, and there are no internal defects such as pores. Figure 4 It is a target blank picture, and the surface flatness is good, less than 0.1 μm.

[0068] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method of producing a NiCrCoAlY target material, characterized by, The method comprises the following steps: (1) melting and casting Ni, Al, Cr and Co under vacuum to obtain a NiCrCoAl alloy ingot; (2) crushing and grinding the NiCrCoAl alloy ingot to obtain a NiCrCoAl alloy powder; (3) mixing the NiCrCoAl alloy powder and Y powder, and sequentially performing cladding, molding, degassing and hot isostatic pressing sintering to obtain the NiCrCoAlY target material; the temperature of the hot isostatic pressing sintering is 750-1200℃, the pressure is 120-180MPa, the holding time is 2-6h, and the heating rate is 3-8℃ / min during the heating process.

2. The method of claim 1, wherein the NiCrCoAlY target is prepared by the steps of: In step (3), the temperature of the hot isostatic pressing sintering is 850-1000℃. ​ 3. The method of claim 1, wherein the NiCrCoAlY target is prepared by the steps of: In step (1), the mass percentage of Ni, Cr, Co and Al in the NiCrCoAl alloy ingot is respectively: Ni 20-40%, Al 10-20%, Cr 10-20% and Co 20-40%. ​ 4. The method of claim 1, wherein the NiCrCoAlY target is prepared by the steps of: In step (1), the melting temperature is 1300-1800℃; and in step (1), the casting temperature is 1300-1800℃. ​ 5. The method of claim 1, wherein the NiCrCoAlY target is prepared by the steps of: In step (2), the crushing comprises at least one of ball milling and jet milling. ​ 6. The method of claim 1, wherein the NiCrCoAlY target is prepared by the steps of: In step (3), the mixing specifically comprises the following steps: ball milling the NiCrCoAl alloy powder and Y powder in a ball-to-powder mass ratio of 0.1-0.8 under an inert gas; the inert gas comprises at least one of nitrogen, argon and helium. ​ 7. The method of claim 1, wherein the NiCrCoAlY target is prepared by the steps of: In step (3), the mass percentage of the Y powder in the NiCrCoAlY target material is 0.2-4%. ​ 8. The method of claim 1, wherein the NiCrCoAlY target is prepared by the steps of: In step (3), the temperature is 200-600℃; the vacuum degree in the package after degassing is less than 5x10 -4 Pa; in step (3), the mesh number of the NiCrCoAl alloy powder is 10-300 mesh; the mesh number of the Y powder is 50-450 mesh. ​ 9. A NiCrCoAlY target material prepared by the method of any one of claims 1-8.

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