Amorphous zr-co-al alloy coating for titanium alloy and method for manufacturing the same

Abstract

The application belongs to the technical field of surface coating, and discloses an amorphous Zr-Co-Al alloy coating for titanium alloy and a preparation method thereof. Zirconium with a mass fraction of 46-56 parts, cobalt with a mass fraction of 28-46 parts and aluminum with a mass fraction of 8-16 parts are subjected to suction casting to obtain a Zr-Co-Al alloy rod. The Zr-Co-Al alloy rod is subjected to arc welding on the surface of a titanium alloy plate to obtain an amorphous Zr-Co-Al alloy coating. The alloy coating obtained by the application can effectively improve the wear resistance and surface hardness of the titanium alloy base material, and is suitable for the preparation and repair of industrial structural parts.

Description

Technical Field

[0001] This invention relates to the field of surface coating technology, and in particular to an amorphous Zr-Co-Al alloy coating for titanium alloys and its preparation method. Background Technology

[0002] TC4 titanium alloy has advantages such as light weight, high strength, and good corrosion resistance, and is widely used in aerospace and civilian industries. However, TC4 titanium alloy has low hardness and poor friction performance, which greatly reduces its service life in friction components and limits its application in many fields.

[0003] Surface coating is an effective way to improve the wear resistance of titanium alloys. Research on amorphous materials is one of the most active and fastest-growing fields in modern materials science. Compared with ordinary steel, amorphous alloys are used in material surfaces, special components, and structural parts due to their higher wear resistance.

[0004] Therefore, the research on developing a high-strength, high-hardness, and wear-resistant amorphous Zr-Co-Al alloy coating is of great significance for the application of titanium alloys in friction-resistant and wear-resistant working conditions. Summary of the Invention

[0005] In view of this, the present invention provides an amorphous Zr-Co-Al alloy coating for titanium alloys and its preparation method, the purpose of which is to solve the problems of poor wear resistance, low strength and hardness of existing titanium alloy coatings.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a method for preparing an amorphous Zr-Co-Al alloy coating for titanium alloys, comprising the following steps:

[0008] (1) Zr-Co-Al alloy rods were prepared by vacuum casting zirconium, cobalt and aluminum;

[0009] (2) The Zr-Co-Al alloy rod is arc welded on the surface of the titanium alloy plate to obtain an amorphous Zr-Co-Al alloy coating.

[0010] Preferably, the mass fractions of zirconium, cobalt and aluminum in step (1) are 46 to 56 parts of zirconium, 28 to 46 parts of cobalt and 8 to 16 parts of aluminum.

[0011] Preferably, the melting current of the suction casting in step (1) is 170-190A, the number of suction castings is 4-6, and the heat preservation time after suction casting is 8-12 minutes.

[0012] Preferably, the diameter of the Zr-Co-Al alloy rod in step (1) is 2 to 4 mm, and the length of the Zr-Co-Al alloy rod is 85 to 95 mm.

[0013] Preferably, the thickness of the titanium alloy plate in step (2) is 5 to 10 mm.

[0014] Preferably, the arc welding in step (2) is tungsten inert gas welding.

[0015] Preferably, the voltage for tungsten inert gas welding is 15-20V and the current is 80-100A.

[0016] Preferably, the arc welding torch moving speed of the tungsten inert gas (TIG) welding is 2-4 mm / s, the shielding gas of the TIG welding is helium, and the flow rate of the shielding gas is 5-10 L / min.

[0017] The present invention also provides an amorphous Zr-Co-Al alloy coating obtained by the preparation method of the aforementioned amorphous Zr-Co-Al alloy coating for titanium alloys.

[0018] Preferably, the thickness of the amorphous Zr-Co-Al alloy coating is 0.9 to 2 mm.

[0019] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention employs tungsten inert gas welding (TIG welding) to prepare an amorphous Zr-Co-Al alloy coating on the surface of TC4 titanium alloy. The coating consists of a composite diffusion layer composed of ZrCo, CoTi2, and Zr3Al phases. The surface hardness of this diffusion layer can reach over 540 HV, and the thickness can reach over 1 mm. This effectively improves the wear resistance and surface hardness of TC4 titanium alloy, making it suitable for the preparation and repair of industrial structural parts. TIG welding is highly adaptable to the form and size of the weldment, and the welding equipment is low-cost and flexible in operation. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0022] Figure 1 This is a SEM image of the cross-section of the amorphous Zr-Co-Al alloy coating on the surface of TC4 titanium alloy in Example 1;

[0023] Figure 2The X-ray diffraction pattern of the cross section of the amorphous Zr-Co-Al alloy coating obtained in Example 1;

[0024] Figure 3 The image shows the hardness of the cross-section of the amorphous Zr-Co-Al alloy coating obtained in Example 1. Detailed Implementation

[0025] This invention provides a method for preparing an amorphous Zr-Co-Al alloy coating for titanium alloys, comprising the following steps:

[0026] (1) Zr-Co-Al alloy rods were prepared by vacuum casting zirconium, cobalt and aluminum;

[0027] (2) The Zr-Co-Al alloy rod is arc welded on the surface of the titanium alloy plate to obtain an amorphous Zr-Co-Al alloy coating.

[0028] In this invention, the mass fractions of zirconium, cobalt and aluminum in step (1) are 46-56 parts of zirconium, 28-46 parts of cobalt and 8-16 parts of aluminum. Preferably, the mass fraction of zirconium is 48-54 parts, more preferably 50-52 parts, the mass fraction of cobalt is 30-44 parts, more preferably 34-38 parts, and the mass fraction of aluminum is 10-14 parts, more preferably 11-13 parts.

[0029] In this invention, the purity of zirconium is preferably greater than or equal to 99.95%, more preferably greater than or equal to 99.96%, and even more preferably greater than or equal to 99.97%. The particle diameter of zirconium is preferably 1 to 5 mm, more preferably 2 to 4 mm, and even more preferably 3 mm.

[0030] In this invention, the purity of cobalt is preferably greater than or equal to 99.98%, more preferably greater than or equal to 99.99%, and the particle diameter of cobalt is preferably 1 to 5 mm, more preferably 2 to 4 mm, and even more preferably 3 mm.

[0031] In this invention, the purity of aluminum is preferably greater than or equal to 99.999%, and the particle diameter of aluminum is preferably 1 to 5 mm, more preferably 2 to 4 mm, and even more preferably 3 mm.

[0032] In this invention, the combination of Ti and Co has high hardness and strong atomic bonds, which can modify the surface of TC4 titanium alloy, thereby enhancing the wear resistance of the coating material.

[0033] In this invention, the melting current of the suction casting in step (1) is preferably 170-190A, more preferably 173-188A, and even more preferably 178-184A. The number of suction castings is preferably 4-6 times, and even more preferably 5 times, to ensure the uniformity of the composition. The heat preservation time after suction casting is preferably 8-12 minutes, more preferably 9-11 minutes, and even more preferably 10 minutes.

[0034] In this invention, the vacuum degree of suction casting is preferably 0.8 × 10⁻⁶. -3 ~1.2×10 -3 Pa, more preferably 1×10 - 3 Pa, the protective gas is preferably argon, and the vacuum degree after filling with argon is preferably -0.05 MPa.

[0035] In this invention, the suction casting in step (1) is preferably water-cooled copper mold suction casting, and the Zr-Co-Al alloy rod is preferably washed with acetone after suction casting.

[0036] In this invention, the diameter of the Zr-Co-Al alloy rod in step (1) is preferably 2-4 mm, more preferably 2.5-3.8 mm, and even more preferably 2.8-3.4 mm. The length of the Zr-Co-Al alloy rod is preferably 85-95 mm, more preferably 88-94 mm, and even more preferably 90-92 mm.

[0037] In this invention, the thickness of the titanium alloy plate in step (2) is preferably 5-10 mm, more preferably 6-9 mm, and even more preferably 7-8 mm. The titanium alloy plate is preferably a TC4 titanium alloy plate.

[0038] In this invention, before arc welding, the titanium alloy plate in step (2) is preferably polished, cleaned and dried in sequence; polishing is preferably done with sandpaper until the surface of the titanium alloy is bright and flat to remove contaminants such as oxides and rust from the surface of the titanium alloy plate. The grit of the sandpaper is preferably 600 to 2000 mesh, more preferably 1000 to 1800 mesh, and more preferably 1200 to 1600 mesh. The cleaning reagent is preferably acetone.

[0039] In this invention, the arc welding in step (2) is preferably tungsten inert gas welding.

[0040] In this invention, the voltage for tungsten inert gas welding is preferably 15-20V, more preferably 16-19V, and even more preferably 17-18V, and the current is preferably 80-100A, more preferably 88-98A, and even more preferably 92-94A.

[0041] In this invention, the preferred moving speed of the arc welding torch for gas tungsten inert gas (GTIG) welding is 2-4 mm / s, more preferably 3 mm / s, the preferred shielding gas for GTIG welding is helium, and the preferred flow rate of the shielding gas is 5-10 L / min, more preferably 6-9 L / min, and even more preferably 7-8 L / min.

[0042] The present invention also provides an amorphous Zr-Co-Al alloy coating obtained by the preparation method of the aforementioned amorphous Zr-Co-Al alloy coating for titanium alloys.

[0043] In this invention, the thickness of the amorphous Zr-Co-Al alloy coating is preferably 0.9-2 mm, more preferably 1.1-1.8 mm, and even more preferably 1.4-1.6 mm. If the coating is too thin, the service life of the coating will be shortened, and if the coating is too thick, the weight of the titanium alloy substrate will be increased, resulting in material waste and poor economic benefits.

[0044] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1

[0046] The amorphous Zr-Co-Al alloy coating for titanium alloys was prepared from the following raw materials in parts by weight: 46 parts zirconium (purity 99.99%, particle size 3 mm), 46 parts cobalt (purity 99.98%, particle size 3 mm) and 8 parts aluminum (purity 99.999%, particle size 3 mm).

[0047] A 10mm thick TC4 titanium alloy plate was sanded with 1200 grit sandpaper until the surface of the TC4 titanium alloy plate was bright and flat. Then it was washed with acetone and dried to obtain the pre-treated TC4 titanium alloy plate.

[0048] Zirconium, cobalt, and aluminum metal particles were water-cooled and vacuum-cast in a copper mold at a melting current of 180A (vacuum degree 1×10). -3 Pa, the protective gas is argon, and argon is filled to a vacuum degree of -0.05MPa). The copper mold is used for casting 5 times. After casting, the sample is kept in the copper mold for 10 minutes and then the alloy rod is cleaned with acetone to obtain a Zr-Co-Al alloy rod with a diameter of 4mm and a length of 90mm.

[0049] The Zr-Co-Al alloy rod was placed on the pretreated TC4 titanium alloy plate and arc welded with tungsten inert gas (TIG) at a voltage of 15V and a current of 80A. The arc welding gun moved at a speed of 2mm / s and the helium gas flow rate was 5L / min, resulting in a 1mm thick dense and uniform amorphous Zr-Co-Al alloy coating.

[0050] Example 2

[0051] The amorphous Zr-Co-Al alloy coating for titanium alloys was prepared from the following raw materials in parts by weight: 45 parts zirconium (purity 99.99%, particle size 3 mm), 45 parts cobalt (purity 99.98%, particle size 3 mm) and 10 parts aluminum (purity 99.999%, particle size 3 mm).

[0052] A 5mm thick TC4 titanium alloy plate was polished with 1800-grit sandpaper until the surface of the TC4 titanium alloy plate was bright and flat. Then it was washed with acetone and dried to obtain the pre-treated TC4 titanium alloy plate.

[0053] Zirconium, cobalt, and aluminum metal particles were water-cooled and vacuum-cast in a copper mold at a melting current of 185A (vacuum degree 1×10). -3 Pa, the protective gas is argon, and argon is filled to a vacuum degree of -0.05MPa). The copper mold is used for casting 6 times. After casting, the sample is kept in the copper mold for 10 minutes and then the alloy rod is cleaned with acetone to obtain a Zr-Co-Al alloy rod with a diameter of 3mm and a length of 90mm.

[0054] The Zr-Co-Al alloy rod was placed on the pretreated TC4 titanium alloy plate and arc welded with tungsten inert gas (TIG) at a voltage of 15V and a current of 90A. The arc welding gun moved at a speed of 3mm / s and the helium gas flow rate was 8L / min, resulting in a dense and uniform amorphous Zr-Co-Al alloy coating with a thickness of 0.9mm.

[0055] Example 3

[0056] The amorphous Zr-Co-Al alloy coating for titanium alloys was prepared from the following raw materials in parts by weight: 56 parts zirconium (purity 99.99%, particle size 3 mm), 28 parts cobalt (purity 99.98%, particle size 3 mm) and 16 parts aluminum (purity 99.999%, particle size 3 mm).

[0057] A 10mm thick TC4 titanium alloy plate was polished with 800-grit sandpaper until the surface of the TC4 titanium alloy plate was bright and flat. Then it was washed with acetone and dried to obtain the pre-treated TC4 titanium alloy plate.

[0058] Zirconium, cobalt, and aluminum metal particles were water-cooled and vacuum-cast in a copper mold at a melting current of 180A (vacuum degree 1×10). -3 Pa, the protective gas is argon, and argon is filled to a vacuum degree of -0.05MPa). The copper mold is used for casting 5 times. After casting, the sample is kept in the copper mold for 10 minutes and then the alloy rod is cleaned with acetone to obtain a Zr-Co-Al alloy rod with a diameter of 3mm and a length of 90mm.

[0059] The Zr-Co-Al alloy rod was placed on the pretreated TC4 titanium alloy plate, and tungsten inert gas welding was performed with a voltage of 20V and a current of 100A. The arc welding gun moved at a speed of 4mm / s and the helium gas flow rate was 10L / min, resulting in a dense and uniform amorphous Zr-Co-Al alloy coating with a thickness of 1.2mm.

[0060] The SEM image of the cross-section of the amorphous Zr-Co-Al alloy coating on the surface of TC4 titanium alloy in Example 1 is shown below. Figure 1 As shown. By Figure 1 It is evident that the TC4 matrix has a needle-like structure, the amorphous Zr-Co-Al alloy coating contains a large number of dendrites, and the matrix and coating exhibit good bonding without defects such as cracks or pores.

[0061] The X-ray diffraction pattern of the cross-section of the amorphous Zr-Co-Al alloy coating obtained in Example 1 is shown below. Figure 2 As shown. By Figure 2 As can be seen, diffuse scattering peaks are present in the spectrum, indicating the presence of an amorphous phase in the composite coating. In addition, diffraction peaks of intermetallic compounds such as Zr3Al and CoTi2 can be detected. The analysis results show that the coating contains a large number of intermetallic compounds, which can improve the hardness and wear resistance of the coating.

[0062] The hardness diagram of the cross-section of the amorphous Zr-Co-Al alloy coating obtained in Example 1 is shown below. Figure 3 As shown. By Figure 3 It is known that the coating hardness can reach up to 623 HV, while the substrate hardness is 316 HV. The surface hardness of the coating is approximately twice that of the substrate. In the central region of the coating, the hardness value decreases sharply with increasing distance from the surface (i.e., closer to the substrate), eventually reaching the substrate hardness value. This is because the microstructure varies in different regions during the cooling process of the welded sample due to the influence of the cooling rate. The coating surface cools the fastest and is most prone to amorphous formation, thus exhibiting the highest strength. Solid solution exists in the central region of the coating and substrate, resulting in a higher hardness value in the central region compared to the substrate.

[0063] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an amorphous Zr-Co-Al alloy coating for titanium alloys, characterized in that, Includes the following steps: (1) Zr-Co-Al alloy rods were prepared by vacuum casting zirconium, cobalt and aluminum; (2) Arc welding is performed on the surface of a titanium alloy plate to obtain an amorphous Zr-Co-Al alloy coating. The mass fractions of zirconium, cobalt and aluminum mentioned in step (1) are 46-56 parts of zirconium, 28-46 parts of cobalt and 8-16 parts of aluminum; The arc welding in step (2) is tungsten inert gas welding, with a voltage of 15~20V and a current of 80~100A.

2. The method for preparing an amorphous Zr-Co-Al alloy coating for titanium alloys according to claim 1, characterized in that, The melting current for suction casting in step (1) is 170~190A, the number of suction castings is 4~6, and the holding time after suction casting is 8~12min.

3. The method for preparing an amorphous Zr-Co-Al alloy coating for titanium alloys according to claim 2, characterized in that, The diameter of the Zr-Co-Al alloy rod in step (1) is 2~4mm, and the length of the Zr-Co-Al alloy rod is 85~95mm.

4. The method for preparing an amorphous Zr-Co-Al alloy coating for titanium alloys according to claim 2 or 3, characterized in that, The thickness of the titanium alloy plate in step (2) is 5~10mm.

5. The method for preparing an amorphous Zr-Co-Al alloy coating for titanium alloys according to claim 1, characterized in that, The arc welding torch moving speed of tungsten inert gas (TIG) welding is 2~4 mm / s, and the shielding gas for TIG welding is helium with a flow rate of 5~10 L / min.

6. The amorphous Zr-Co-Al alloy coating obtained by the preparation method of the amorphous Zr-Co-Al alloy coating for titanium alloys according to any one of claims 1 to 5.

7. The amorphous Zr-Co-Al alloy coating according to claim 6, characterized in that, The thickness of the amorphous Zr-Co-Al alloy coating is 0.9~2mm.

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