TiAl alloy target material with heat sink layer and preparation method of TiAl alloy target material

Abstract

The invention relates to the technical field of powder metallurgy, in particular to a TiAl alloy target material with a heat sink layer and a preparation method of the TiAl alloy target material. The preparation method specifically comprises the following steps of preparation of a pure Ti module, preparation of a TiAl module, SPS sintering and finished product processing. Wherein in the SPS sintering process, the pure Ti module and the TiAl module are stacked in a graphite mold according to the mode that the pure Ti module is located on the lower portion and the TiAl module is located on the upper portion, and sintering is conducted in the SPS process. The Al powder and the Ti powder are mixed and then subjected to SPS rapid sintering, meanwhile, the pure Ti heat sink layer is introduced in the sintering process, especially for the alloy target with the Al content smaller than or equal to 30%, the target with the high relative density can be obtained, meanwhile, the problem of breakage of the target in the using process is solved, and the method is mainly applied to the field of PVD coating.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of powder metallurgy, in particular to a TiAl alloy target material with a heat sink layer and a preparation method thereof. BACKGROUND

[0002] With the continuous development of science and technology, surface treatment technology is increasingly widely used in the industrial field. Among them, TiAlN aluminum nitride Ti coating as one of the important surface treatment technologies has the advantages of high hardness, good toughness, excellent thermal stability and oxidation resistance, etc. In addition, it also has the advantages of low thermal expansion coefficient and good adhesion strength, etc., making it become the preferred surface treatment scheme for various mechanical parts, especially those parts that require to work under high-speed cutting and high load conditions. TiAlN is widely used in various fields due to its excellent performance, including aerospace automobile manufacturing industry, precision instrument processing and mold production industries, especially in tool manufacturing, because it can significantly prolong the service life of tools and improve production efficiency and quality level.

[0003] The main way to obtain TiAlN coating is physical vapor deposition (PVD) and chemical vapor deposition (CVD). Among them, PVD coating technology has made comprehensive progress in improving control technology, increasing plasma density, increasing magnetic field strength, improving the shape of the cathode target, realizing computer full-automatic control of the process, etc. and has been widely applied, becoming the mainstream hard coating means. In the process of preparing TiAlN coating by PVD, TiAl target material is used as the direct raw material, and the target material is ionized by sputtering or arc evaporation, and then deposited on the corresponding workpiece.

[0004] At present, for the target material with high Al content (≥30at%), it can be prepared by hot isostatic pressing (HIP) at 400-500℃ sintering. The relative density of the target material can reach more than 99%. However, when the Al content in the target material is less than 30at%, the sintering temperature is relatively low due to the low aluminum content, which leads to a lower relative density of the target material and more internal pores, seriously affecting the quality of the final coating. If the HIP temperature is further increased, the Al powder and the package are easily melted due to the relatively low melting point of Al. In addition, for TiAl target materials with low aluminum content, the plasticity of the target material decreases due to the decrease of chlorine content, and during use, the target material is prone to fracture under the simultaneous action of high temperature generated by sputtering and cooling water pressure.

[0005] In order to solve the problem of low relative density of the target material, patent 202310904370.7 proposes to use TiAl alloy powder as the source material of Al powder, and then mix with Ti powder and sinter at a high HIP temperature to form a TiAl alloy target material with high relative density. However, TiAl alloy powder needs to be prepared by atomization, which greatly increases the process and cost of the target material, which is not conducive to large-scale industrial production. SUMMARY

[0006] In order to comprehensively solve the above problems, the present application provides a TiAl alloy target material with a heat sink layer and a preparation method thereof. The present application mixes Al powder and Ti powder and then sintering by SPS, and at the same time introduces a pure Ti heat sink layer during sintering. Especially for alloy target materials with Al content ≤30%, the problem of target material fracture during use can be solved while obtaining a target material with high relative density, mainly applied in the field of PVD coating.

[0007] In a first aspect, the present application provides a preparation method of a TiAl alloy target material with a heat sink layer, which adopts the following technical scheme:

[0008] A preparation method of a TiAl alloy target material with a heat sink layer, the preparation method specifically comprises the following steps:

[0009] Preparation of pure Ti module: using high-purity Ti powder to prepare pure Ti module; die pressing to a relative density > 60%;

[0010] Preparation of TiAl module: using Ti powder and Al powder to prepare TiAl module; die pressing to a relative density > 60%; the ratio of elements is Ti 70-99at%, Al 1-30at%;

[0011] SPS sintering: according to the pure Ti module at the bottom and the TiAl module on the top, the pure Ti module and the TiAl module are stacked in a graphite mold and sintered in SPS;

[0012] Sintering conditions: during the SPS sintering process, short-term heat preservation treatment needs to be carried out in the range of 450-650℃, the heat preservation time is 5-15min, and then the temperature is raised to 700-1200℃ for heat preservation sintering; the sintering pressure is 10-40MPa; the heat preservation and pressure holding time is 0.1-0.5h;

[0013] Finished product processing: after sintering, the target product is processed.

[0014] In the product preparation process, the pure Ti module is below and the TiAl module is above, and Ti is selected as the heat sink layer, so that the heat sink layer and the target material are combined without transition section, and the target material can bear a large water pressure in the use process, thereby avoiding the rupture caused by the brittleness of the TiAl target material.

[0015] In the sintering process, short-term heat preservation treatment in the range of 450-650℃ can fully alloy Ti and Al in the target material at this temperature, so that Al exists in the form of TiAl alloy, and sintering failure caused by Al melting at high temperature is avoided.

[0016] Optionally, the purity of the Ti powder of the heat sink layer is ≥2N5, and the particle size is 100-325 mesh.

[0017] In a specific embodiment, the particle size is -100 mesh, -200 mesh, -325 mesh or an interval particle size between the particle size ranges, preferably -200 mesh.

[0018] Optionally, the purity of the Ti powder in the TiAl target material is ≥2N8, and the particle size is 100-325 mesh.

[0019] In a specific embodiment, the particle size is -100 mesh, -200 mesh, -325 mesh or an interval particle size between the particle size ranges, preferably -200 mesh.

[0020] Optionally, the purity of the Al powder in the TiAl target material is ≥99.8wt%, and the particle size is 100-325 mesh.

[0021] In a specific embodiment, the particle size is -200 mesh, -325 mesh or an interval particle size between the particle size ranges, preferably -325 mesh.

[0022] Optionally, in the SPS sintering process, short-term heat preservation treatment in the range of 450-650℃ is required, and the heat preservation time is 5-15 min.

[0023] Optionally, the pressure of the molding in step (1) is 400-800 tons.

[0024] Optionally, the pressure of the molding in step (2) is 400-800 tons.

[0025] In a second aspect, the application provides a TiAl alloy target material with a heat sink layer prepared by the above preparation method.

[0026] In summary, the application includes at least one of the following beneficial technical effects:

[0027] The conventional TiAl target material is prepared by a hot isostatic pressing (HIP) process. However, for the target material with a low Al content (≤30%), due to the limitation of sintering temperature, the relative density of the target material is low, the target material is porous inside, the plasticity is poor, and the strength is low, which seriously affects the quality of the coating and the safe use of the equipment.

[0028] The present application adopts Al powder and Ti powder, and then realizes the preparation of the low Al content TiAl target material with high density, high strength, double-layer composite and low cost by SPS rapid sintering and introducing a pure Ti heat sink in the sintering process. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The present application provides a process flow chart of the preparation method of the TiAl alloy target material with a heat sink layer. DETAILED DESCRIPTION

[0030] Before describing the embodiments of the present application in detail, it should be understood that the terms used herein are only for the purpose of describing specific embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as understood by a person of ordinary skill in the art to which the term belongs.

[0031] It should be noted that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. Further, in the description of the present application, unless otherwise stated, the meaning of "multiple" is two or more.

[0032] The endpoints of the ranges and any values disclosed in the present application are not limited to the precise values stated. The ranges or values should be construed to include values approximately around the ranges or values. For numerical ranges, the endpoints of the various ranges are not included between them, the endpoints of the various ranges and individual point values, and the individual point values can be combined to form one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] In the present application, the term "comprising" or "including" is an open expression, that is, it includes the contents indicated in the present application, but does not exclude other aspects.

[0034] The present application provides a TiAl alloy target material with a heat sink layer. The TiAl alloy target material includes the following percentages of elements: Ti 70-99 at%, Al 1-30 at%. The heat sink layer is made of high-purity Ti powder, and the thickness of the heat sink layer is 2-6 mm.

[0035] The application also provides a preparation method of the TiAl alloy target with the heat sink layer. The raw materials used in the preparation method are high-purity Ti powder, Ti powder and Al powder.

[0036] Combining Figure 1 The preparation method specifically comprises the following steps:

[0037] (1) Preparation of a pure Ti module: Ti powder is loaded into a mold, and is pressed to a relative density of > 60%, and is taken out after demolding to obtain a pure Ti module.

[0038] The purity of the Ti powder is ≥ 2N5, and the particle size is -100 mesh, -200 mesh, -325 mesh or an interval particle size between the particle size ranges, and the particle size is preferably -200 mesh.

[0039] The pressure used for pressing is 400-800 tons, and the pressure is preferably 600-700 tons.

[0040] (2) Preparation of a TiAl module: Ti powder and Al powder are mixed in a certain proportion to obtain TiAl powder. The TiAl powder is loaded into the mold of step (1), and is pressed to a relative density of > 60%, and is taken out after demolding to obtain a TiAl module.

[0041] The purity of the Ti powder is ≥ 2N8, and the particle size is -100 mesh, -200 mesh, -325 mesh or an interval particle size between the particle size ranges, and the particle size is preferably -325 mesh.

[0042] The purity of the Al powder is ≥ 2N8, and the particle size is -200 mesh, -325 mesh or an interval particle size between the particle size ranges, and the particle size is preferably -325 mesh.

[0043] The pressure used for pressing is 400-800 tons. Preferably, the pressure used for pressing is 500-600 tons.

[0044] The mold used in the above steps is selected according to the shape of the target, and a circular or square mold can be selected.

[0045] (3) SPS sintering: the pure Ti module and the TiAl module are stacked in a graphite mold in a manner that the pure Ti module is below and the TiAl module is above, and are placed in a spark plasma sintering furnace (SPS) for sintering.

[0046] The sintering conditions are as follows: the sintering temperature is 700-1200℃; the pressure is 10-40 MPa; and the holding time is 0.1-0.5 h. During the SPS sintering process, short-term holding treatment is required in the range of 450-650℃, and the holding time is 5-15 min.

[0047] (4) Product processing: after sintering, the mold is demolded, and the target product is processed.

[0048] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application. The embodiments described below are exemplary and are only used to explain the present application, and cannot be understood as limitations of the present application.

[0049] Unless otherwise specified in the embodiments, the techniques or conditions are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. Unless otherwise specified, the reagents or instruments used are conventional products that can be obtained commercially.

[0050] The present application will be further described in detail below in combination with the embodiments and test results.

[0051] Embodiments

[0052] Embodiment 1

[0053] The present embodiment provides a TiAl alloy target material with a heat sink layer.

[0054] The preparation method of the TiAl alloy target material described above specifically comprises the following steps:

[0055] (1) Preparation of pure Ti module

[0056] Pure Ti powder with a purity of ≥2N5 is loaded into a cylindrical mold for molding until the relative density is >60%, and then taken out after demolding to obtain a pure Ti module for standby use. The particle size of the high-purity Ti powder is -200 mesh. The pressure used for molding is 550 tons.

[0057] (2) Preparation of TiAl module

[0058] Ti powder and Al powder used for preparing the target material substrate are weighed according to the proportion and then uniformly mixed to obtain TiAl powder. The proportion of elements in the obtained TiAl powder is: Ti 70 at%, Al 30 at%. Among them, the purity of Ti powder and Al powder is >2N8, and the particle size is 325 mesh.

[0059] The TiAl powder is loaded into the cylindrical mold of step (1) for molding until the relative density is >60%, and then taken out after demolding to obtain a TiAl module for standby use. The pressure used for molding is 500 tons.

[0060] (3) SPS sintering

[0061] The pure Ti module and the TiAl module are stacked, with the pure Ti module placed below the TiAl module, loaded into a graphite mold, and placed in a spark plasma sintering furnace for sintering. The sintering temperature is 950℃, the pressure is 30MPa, and the holding time under pressure is 0.3h.

[0062] In the SPS sintering process, a short holding treatment at 550℃ is needed to fully alloy Ti and Al, and the holding time is 10 min.

[0063] (4) Product processing: After sintering, the blank is demolded, and then the target product is processed according to the drawing requirements.

[0064] Example 2

[0065] The embodiment provides a TiAl alloy target material with a heat sink layer. The difference from the embodiment 1 is that the atomic percentage content of each element is: Ti 80at%, Al 20at%. The remaining steps are consistent with the embodiment 1.

[0066] Example 3

[0067] The embodiment provides a TiAl alloy target material with a heat sink layer. The difference from the embodiment 1 is that the atomic percentage content of each element is: Ti 90at%, Al 10at%. The remaining steps are consistent with the embodiment 1.

[0068] Example 4

[0069] The embodiment provides a TiAl alloy target material with a heat sink layer. The difference from the embodiment 1 is that the atomic percentage content of each element is: Ti 95at%, Al 5at%. The remaining steps are consistent with the embodiment 1.

[0070] Example 5

[0071] The embodiment provides a TiAl alloy target material with a heat sink layer. The difference from the embodiment 1 is that the atomic percentage content of each element is: Ti 99at%, Al 1at%. The remaining steps are consistent with the embodiment 1.

[0072] Example 6

[0073] Embodiments 6-17 respectively provide a TiAl alloy target material with a heat sink layer. The difference from the embodiment 2 is that the partial parameter setting in the discharge plasma pre-sintering or the thickness of the pure titanium module, as shown in Table 1. The remaining steps are consistent with the embodiment 1.

[0074] Specifically as follows:

[0075] Embodiments 6-8 are different from the embodiment 2 in that the thickness of the pure Ti module.

[0076] Embodiments 9-12 are different from the embodiment 2 in that the sintering temperature.

[0077] Examples 13-15 differ from Example 2 in that pressure is applied.

[0078] Examples 16-17 differ from Example 2 in that the soaking and holding time.

[0079] Table 1 Test results of TiAl alloy target with heat sink layer prepared in the above examples

[0080]

[0081] Note: The measured density is greater than the theoretically calculated density because Ti and Al alloying reaction to form intermetallic compounds occurs at high temperature sintering.

[0082] Comparative Example

[0083] Comparative Example 1

[0084] This comparative example provides a TiAl alloy target. The atomic percentage content of each element of the alloy target is the same as that of Example 1. The difference is that HIP low-temperature sintering is used without a heat sink layer.

[0085] The preparation method is as follows: after mixing Ti powder and Al powder, the mixture is loaded into an aluminum package, vacuum degassing, and then HIP sintering is used, with a sintering temperature of 480°C.

[0086] Comparative Example 2

[0087] This comparative example provides a TiAl alloy target with a heat sink layer. The difference between it and Example 1 is that the atomic percentage content of each element is: Ti 60at%, Al 40at%. The remaining steps are consistent with Example 1.

[0088] The results show that the target with an Al content of 40at% has an Al melting phenomenon during sintering, resulting in sintering failure.

[0089] Performance test

[0090] The target prepared in the above examples and comparative examples is tested for density (Archimedes drainage method) and tensile strength (universal testing machine), respectively.

[0091] The test results are shown in Table 1.

[0092] As can be seen from Table 1, by comparing Examples 1-17 with Comparative Example 1, it can be seen that by mixing Al powder and Ti powder and then rapidly sintering by SPS, while introducing a pure Ti heat sink layer during sintering, a target with a relatively high relative density can be obtained while solving the problem of target fracture during use.

[0093] It can be seen from the comparative examples 1-5 and the comparative example 2 that the technical solution of the present application is more effective for the alloy target with Al content ≤ 30%. When the Al content is 40 at%, the target appears Al melting phenomenon during the sintering process, resulting in sintering failure.

[0094] It can be seen from the comparative example 2 and the examples 6-8 that the present application can obtain a target with higher relative density and higher tensile strength by controlling the thickness of the heat sink layer in the range of 2-6 mm.

[0095] It can be seen from the comparative example 2 and the examples 9-17 that the present application can obtain a target with higher relative density and higher tensile strength by setting the sintering conditions as follows: sintering temperature of 700-1200℃, sintering pressure of 10-40MPa, and holding time of 0.1-0.5h.

[0096] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0097] 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 them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a TiAl alloy target with a heat sink layer, characterized in that, The preparation method specifically includes the following steps: Preparation of pure Ti modules: Pure Ti modules were prepared using Ti powder and molded to a relative density >60%. Preparation of TiAl modules: TiAl modules were prepared using Ti powder and Al powder; they were molded to a relative density >60%; the atomic percentage content of the elements was Ti 70-99 at% and Al 1-30 at% SPS sintering: The pure Ti module and the TiAl module are stacked in a graphite mold with the pure Ti module at the bottom and the TiAl module at the top, and then sintered in SPS. The sintering conditions are as follows: sintering temperature 700-1200℃; sintering pressure 10-40MPa; holding time 0.1-0.5h. Finished product processing: After sintering, the product is demolded and processed into a target material.

2. The preparation method according to claim 1, characterized in that, The purity of the Ti powder used to prepare the pure Ti block is ≥2N5, and the particle size is 100-325 mesh.

3. The preparation method according to claim 1, characterized in that, The Ti powder used to prepare the TiAl block has a purity of ≥2N8 and a particle size of 100-325 mesh.

4. The preparation method according to claim 1, characterized in that, The Al powder has a purity of ≥99.8wt% and a particle size of 100-325 mesh.

5. The preparation method according to claim 1, characterized in that, During the SPS sintering process, a short-term heat treatment is required within the range of 450-650℃, with a holding time of 5-15 minutes.

6. The preparation method according to claim 1, characterized in that, The molding pressure in step (1) is 400-800 tons.

7. The preparation method according to claim 1, characterized in that, The molding pressure in step (2) is 400-800 tons.

8. A TiAl alloy target with a heat sink layer prepared by the preparation method according to any one of claims 1-7.

9. A TiAl alloy target with a heat sink layer as described in claim 8, characterized in that, The thickness of the heat sink layer is 2-6 mm.

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