Titanium alloy-based composite coating structure, method for inhibiting upward dilution of Ti during cladding of wear-resistant layer on surface of titanium alloy and application of titanium alloy-based composite coating structure

Abstract

The invention provides a titanium alloy-based composite coating structure, a method for inhibiting upward dilution of Ti during cladding of a wear-resistant layer on the surface of a titanium alloy and application of the titanium alloy-based composite coating structure. The method comprises the steps that an aluminum bronze barrier layer is formed on a titanium alloy substrate, the phase structure of the aluminum bronze barrier layer comprises a Cu phase and a Cu2TiAl phase, the Cu phase and the Cu2TiAl phase are each of an FCC crystal structure, and the Cu2TiAl phase is formed by reacting Ti in the titanium alloy substrate with Cu and Al; the volume ratios of a Cu phase and a Cu2TiAl phase in the aluminum bronze barrier layer are 40%-45% and 55%-60% respectively; and forming the transition alloy wear-resistant layer on the titanium alloy substrate with the aluminum bronze barrier layer by adopting a laser cladding technology. The aluminum bronze barrier layer is arranged to reduce upward dilution of Ti elements in the cladding process of the transition alloy wear-resistant layer, generation of a large number of hard brittle phases is avoided, the difference between the wear-resistant layer and a titanium alloy matrix in the thermophysical property aspect is relieved, and coating cracking is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of titanium alloy surface erosion-resistant protection, and particularly relates to a titanium alloy-based composite coating structure, a method for inhibiting Ti upward dilution during cladding of a wear-resistant layer on a titanium alloy surface, and application. BACKGROUND

[0002] In the development and utilization of marine resources, titanium alloys with small density and high specific strength have been widely used. Titanium alloy is a high-strength material with almost no significant difference in fatigue limit in seawater and air, and is therefore called marine metal. Compared with corrosion-resistant materials such as stainless steel and aluminum alloy, titanium alloy has better resistance to pitting corrosion, crevice corrosion, intergranular corrosion and uniform corrosion, and excellent corrosion resistance, which makes titanium alloy an important marine material and its application in various marine equipment is increasing day by day. However, the titanium alloy surface has low hardness and lacks work hardening ability. In the complex service conditions of marine environment, serious material loss often occurs due to the combined action of wear and corrosion. Therefore, it is necessary to introduce a protective coating with excellent corrosion and wear resistance to protect such titanium alloy components.

[0003] Laser cladding is a method of using a high-energy laser beam to melt the cladding material and the substrate at the same time to form a firm metallurgical bond. The prepared coating has a dense microstructure and excellent performance, and is a common preparation method for surface protective coating of large marine equipment under heavy load and high shear conditions. The commonly used wear-resistant and corrosion-resistant laser cladding coating mainly focuses on cobalt-based and nickel-based transition group alloy coatings. However, for the preparation of titanium alloy surface coating, the thermal expansion coefficients and other thermal properties of cobalt-based and nickel-based coatings do not match those of titanium alloy, which may cause cracking of the coating due to residual thermal stress. At the same time, the diluted titanium element in the laser cladding process often reacts with transition elements to form hard and brittle phases such as Laves phase and sigma phase. The precipitation of these brittle phases will significantly reduce the toughness of the coating, and directly lead to cracking of the coating under high thermal stress, which seriously restricts the application of high-performance coatings. SUMMARY

[0004] To solve all or part of the above technical problems, the present application provides the following technical solutions:

[0005] The first aspect of the present application provides a method for inhibiting Ti upward dilution during cladding of a wear-resistant layer on a titanium alloy surface, comprising:

[0006] An aluminum bronze barrier layer is formed on the titanium alloy substrate, the phase structure of the aluminum bronze barrier layer includes Cu phase and Cu2TiAl phase, the Cu phase and the Cu2TiAl phase are both FCC crystal structures, and the Cu2TiAl phase is formed by the reaction of Ti element in the titanium alloy substrate with Cu and Al; the volume fractions of the Cu phase and the Cu2TiAl phase in the aluminum bronze barrier layer are 40% to 45% and 55% to 60%, respectively.

[0007] A transition metal alloy wear-resistant layer is formed on the titanium alloy substrate with the aluminum bronze barrier layer by using laser cladding technology.

[0008] The method provided by the application forms an aluminum bronze barrier layer between the titanium alloy substrate and the transition metal alloy wear-resistant layer to reduce the upward dilution of Ti elements in the titanium alloy substrate to the transition metal alloy wear-resistant layer in the laser cladding process, thereby avoiding the generation of a large number of hard and brittle phases in the transition metal alloy wear-resistant layer. Specifically, in the process of forming the aluminum bronze barrier layer, since the solid solubility of Ti elements in Cu elements is only about 9 at% (900 ℃), the two have a high chemical affinity, and the Cu elements can greatly prevent the upward dilution of Ti elements; at the same time, the aluminum elements contained in the aluminum bronze can enhance the compatibility between the titanium alloy on the one hand, and the Al elements promote the change of the compound types inside the barrier layer, induce the formation of Cu2TiAl with lower energy, promote the consumption of Ti elements, and make a large amount of Cu elements reserved, thereby forming a reticular Cu phase. In addition, the aluminum bronze barrier layer can also alleviate the difference in thermal properties between the wear-resistant layer and the titanium alloy substrate, further improving the cracking problem.

[0009] In some embodiments, based on the barrier effect of the aluminum bronze barrier layer, the Ti content in the transition metal alloy wear-resistant layer derived from the upward dilution of Ti elements in the titanium alloy substrate in the laser cladding process is 3 at% or less.

[0010] In some embodiments, the Cu content in the transition metal alloy wear-resistant layer derived from the aluminum bronze barrier layer in the laser cladding process is 6 at% or less.

[0011] In some embodiments, the thickness of the aluminum bronze barrier layer is 600 μm-670 μm. If the thickness is too low, the aluminum bronze barrier layer is easy to be broken down in the preparation of the transition metal alloy wear-resistant layer, and cannot play a barrier role; if the thickness is too thick, it is easy to cause the accumulation of interface thermal stress to be intensified, and increase the material cost, at the same time, the too thick aluminum bronze layer can introduce too much heat input in the laser cladding process, which can cause the organization of the barrier layer to be coarsened or pores and other defects to be generated, thereby reducing the bonding strength and service reliability of the overall structure. Through systematic research, it is found that when the thickness of the aluminum bronze barrier layer is 600 μm-670 μm, the comprehensive effect of the barrier effect and the structural stability is better.

[0012] In some embodiments, the phase structure of the aluminum bronze barrier layer is composed of Cu phase and Cu2TiAl phase.

[0013] In some embodiments, the method for forming an aluminum bronze barrier layer on a titanium alloy substrate comprises: laser cladding on the titanium alloy substrate using an aluminum bronze powder; wherein the aluminum bronze powder contains 78-82 at% copper and 18-22 at% aluminum.

[0014] In some embodiments, the process conditions for forming the aluminum bronze barrier layer by laser cladding on the titanium alloy substrate specifically include: laser vertical scanning, laser cladding power of 400 W-600 W, cladding scanning speed of 15 mm / s-17 mm / s, overlap rate of 50%-60%, laser focal length of 19 mm-20 mm, and powder feeding rate of 15-20 g / min; the powder feeding gas and the cladding protection gas are both inert atmosphere, and the gas flow rate is 12 L / min-15 L / min.

[0015] In some embodiments, the particle size of the aluminum bronze powder is 15 μm-53 μm.

[0016] In some embodiments, the aluminum bronze powder can use QAl-9 aluminum bronze alloy powder, but is not limited thereto.

[0017] It should be understood that, since the aluminum bronze powder used can also contain other impurity elements, the aluminum bronze barrier layer formed can also contain unavoidable impurity elements. For example, in some embodiments, the aluminum bronze barrier layer contains 0.054 at% or less of Cr element, and / or 0.192 at% or less of Fe element. However, the content of these impurity elements is extremely small, and does not affect the phase organization of the aluminum bronze barrier layer.

[0018] In some embodiments, the transition group alloy wear-resistant layer is a Ni-based multi-principal element wear-resistant layer. The elements contained in the Ni-based multi-principal element wear-resistant layer include Ni, and also include one or a combination of Co, Cr, Fe, and Al. For example, the material of the Ni-based multi-principal element wear-resistant layer includes CoCrNi alloy (CoCrNi medium-entropy alloy), CoCrFeNi alloy (CoCrFeNi high-entropy alloy), or AlCoCrFeNi alloy (for example, AlCoCrFeNi 2.1 dual-phase high-entropy alloy), or other multi-principal element alloy materials derived from CoCrNi.

[0019] In some embodiments, the process conditions for forming the wear-resistant layer of the transition alloy using laser cladding technology include: vertical laser scanning, laser cladding power of 300W~400W, cladding scanning speed of 15~17 mm / s, overlap rate of 50%~60%, laser focal length of 20mm~21mm, powder feeding rate of 20~25 trays / min, and both the powder feeding gas and the cladding protective gas are inert atmospheres with a gas flow rate of 12L / min~15L / min.

[0020] The titanium alloy substrate can be made of, for example, α+β titanium alloys such as TC4, α pure titanium such as TA1 and TA2, β titanium alloys such as TB1 and TB2, or other alloys with titanium as the main element.

[0021] A second aspect of the present invention provides a titanium alloy-based composite coating structure, comprising a titanium alloy substrate and an aluminum bronze barrier layer and a transition alloy wear-resistant layer sequentially formed on the titanium alloy substrate, wherein the titanium alloy-based composite coating structure is obtained based on the method described in any technical solution for inhibiting the upward dilution of Ti when the wear-resistant layer is clad on the surface of the titanium alloy.

[0022] In some embodiments, the Ti content in the transition alloy wear-resistant layer of the titanium alloy-based composite coating structure is less than 3 at%, and / or the Cu content is less than 6 at%. Furthermore, there is no significant Cu enrichment in the transition alloy wear-resistant layer.

[0023] In some embodiments, the coefficient of friction of the titanium alloy-based composite coating structure can reach 0.21~0.35, and the corrosion current density can reach 2.01×10⁻⁶. -8 A / cm 2 Below this, the wear rate can reach 0.21~2.15×10. -6 mm 3 ·N -1 ·m -1 the following.

[0024] A third aspect of the present invention provides a titanium alloy-based composite coating structure, comprising a titanium alloy substrate and an aluminum bronze barrier layer and a transition alloy wear-resistant layer disposed sequentially along a direction away from the titanium alloy substrate;

[0025] The phase structure of the aluminum bronze barrier layer includes a Cu phase and a Cu2TiAl phase, both of which are FCC crystal structures; the volume percentages of the Cu phase and Cu2TiAl phase in the aluminum bronze barrier layer are 40%~45% and 55%~60%, respectively.

[0026] In some embodiments, the titanium alloy substrate is metallurgically bonded to the aluminum bronze barrier layer. For example, the aluminum bronze barrier layer is formed on the titanium alloy substrate using laser cladding technology.

[0027] In some embodiments, the thickness of the aluminum bronze barrier layer is 600 μm to 670 μm.

[0028] In some embodiments, the phase structure of the aluminum bronze barrier layer consists of Cu phase and Cu2TiAl phase.

[0029] In some embodiments, the aluminum bronze barrier layer and the transition alloy wear-resistant layer are metallurgically bonded. For example, the transition alloy wear-resistant layer is formed on the aluminum bronze barrier layer using laser cladding technology.

[0030] In some embodiments, the combination of the aluminum bronze barrier layer and the transition alloy wear-resistant layer is defined as a composite layer, and the chemical elemental composition of this composite layer satisfies the following relationship: Al a Co b Cr c Fe d Ni e Cu f Ti g In the formula, the subscripts a, b, c, d, e, f, and g represent the atomic percentages (%) of the corresponding elements, and satisfy the following conditions: 0 ≤ a ≤ 16.5; 25 ≤ b ≤ 33.4; 25 ≤ c ≤ 33.4; 0 ≤ d ≤ 25; 25 ≤ e ≤ 33.4; 3 ≤ f ≤ 6; 0 ≤ g ≤ 3; a+b+c+d+e+f+g=100. The composite layer of the above components has an FCC or "FCC+BCC" structure, and the wear-resistant layer is often dominated by FCC. It has good work hardening ability during friction, which can achieve good wear resistance. At the same time, the low Cu and Fe content makes the coating have excellent corrosion resistance.

[0031] Further solutions to the "a titanium alloy-based composite coating structure" provided in the third aspect of the present invention, such as a further selection of the wear-resistant layer of a transition alloy, have been specifically described in the first aspect of the present invention, "a method for suppressing the upward dilution of Ti when a wear-resistant layer is clad on the surface of a titanium alloy," and will not be repeated here.

[0032] The fourth aspect of the present invention provides the above-described method for suppressing the upward dilution of Ti when a wear-resistant layer is clad on a titanium alloy surface, or the application of a titanium alloy-based composite coating structure in the preparation of wear-resistant moving parts.

[0033] The fifth aspect of the present invention provides a wear-resistant moving part comprising the titanium alloy-based composite coating structure described in any of the technical solutions.

[0034] In some embodiments, the wear-resistant moving parts include seawater-resistant moving parts.

[0035] Compared with the prior art, the present invention has some or all of the following beneficial effects: The method provided by the present invention forms an aluminum bronze barrier layer between a titanium alloy substrate and a transition alloy wear-resistant layer. On the one hand, the aluminum bronze barrier layer can prevent the titanium element in the substrate from diluting upward during the laser cladding process and generating a brittle phase at the interface of the wear-resistant layer. On the other hand, it can realize the transition of thermal properties such as the coefficient of thermal expansion between the wear-resistant layer and the titanium alloy substrate. The two aspects work together to significantly reduce the cracking of the wear-resistant layer. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application 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 some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1a These are electron microscope comparison images of the titanium alloy-based composite coating structures prepared in Example 1 and Comparative Example 1;

[0038] Figure 1b These are electron microscope comparison images of the titanium alloy-based composite coating structures prepared in Example 2 and Comparative Example 2;

[0039] Figure 1c These are electron microscope comparison images of the titanium alloy-based composite coating structures prepared in Example 3 and Comparative Example 3;

[0040] Figure 2 These are macroscopic morphology comparison images of the coatings obtained by cladding in Examples 1-3 and Comparative Examples 1-3;

[0041] Figure 3 These are electron microscope comparison images of the cross sections of the titanium alloy-based composite coating structures prepared in Example 2 and Comparative Example 4;

[0042] Figure 4 This is a cross-sectional EDS analysis diagram of the titanium alloy-based composite coating structure in Comparative Example 2;

[0043] Figure 5 This is a cross-sectional EDS analysis diagram of the titanium alloy-based composite coating structure in Comparative Example 4;

[0044] Figure 6 This is a cross-sectional EDS analysis diagram of the titanium alloy-based composite coating structure in Example 2;

[0045] Figure 7 These are the XRD patterns of the Ni-based multi-principal-element alloy layers from Examples 1-3.

[0046] Figure 8These are the XRD patterns of the aluminum bronze barrier layer in Example 2 and the pure copper layer in Comparative Example 4;

[0047] Figure 9 These are comparative diagrams of the cross-sectional hardness distribution of the titanium alloy-based composite coating structures in Example 2 and Comparative Example 4;

[0048] Figure 10 The measured potentiodynamic polarization curves of the titanium alloy-based composite coating structures in Examples 1-3 are shown in the test diagram.

[0049] Figure 11 The friction coefficient diagrams are shown for the titanium alloy-based composite coating structures in Examples 1-3;

[0050] Figure 12 The wear rate calculation diagram is shown for the titanium alloy-based composite coating structure in Examples 1-3. Detailed Implementation

[0051] The invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as intended to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.

[0052] In addition, unless otherwise specified, all raw materials used in the following embodiments can be purchased from the market or other sources, and all production and testing equipment used are known in the art, as are the testing methods used.

[0053] Example 1

[0054] This embodiment provides a titanium alloy-based composite coating structure and its preparation method, specifically including the following steps:

[0055] (1) Pre-treatment of TC4 titanium alloy substrate includes: polishing the surface of titanium alloy substrate with 120 mesh, 240 mesh, 400 mesh and 800 mesh sandpaper in sequence, then ultrasonically cleaning with acetone and alcohol for 20~25 min respectively, blowing dry, and preheating to 450℃ in advance.

[0056] (2) An aluminum bronze barrier layer was clad onto a titanium alloy substrate using laser cladding technology. The elemental composition of the aluminum bronze alloy powder used in this embodiment includes: 80.01 at% copper and 19.55 at% aluminum. The aluminum bronze alloy powder was placed in an oven and dried at 80°C for 2 hours.

[0057] The process conditions for cladding the aluminum bronze barrier layer include: under argon protection, a coaxial powder-feeding laser is used with a laser power of 600 W, a cladding scanning speed displacement of 15 mm / s, an overlap rate of 50%, a laser focal length of 19 mm, a powder feeding rate of 15 discs / min, and both the powder feeding gas and the cladding protective gas are argon with a gas flow rate of 12 L / min, thereby forming an aluminum bronze barrier layer with a thickness of approximately 660.8 μm on the aforementioned titanium alloy substrate.

[0058] (3) A CoCrNi coating was formed on the aluminum bronze barrier layer using laser cladding technology. Co, Cr and Ni elemental powders with an equiatomic ratio (33.33 at%) (particle size between 15-53 μm) were taken and placed in a planetary ball mill. The mill was set to a speed of 400 rpm and mixed for 3 h to obtain a uniform mixed powder. The powder was then dried at 80℃ for more than 2 h.

[0059] The process conditions for cladding the CoCrNi coating include: under argon protection, a coaxial powder-feeding laser with a laser power of 400 W, a cladding scanning speed of 15 mm / s, an overlap rate of 50%, a laser focal length of 20 mm, a powder feeding rate of 20 discs / min, and both the powder feeding gas and the cladding protective gas being argon with a gas flow rate of 12 L / min, thereby forming a CoCrNi layer with a thickness of approximately 803.7 μm on the aluminum bronze barrier layer, thus obtaining a titanium alloy-based composite coating structure.

[0060] Example 2

[0061] Example 2 is basically the same as Example 1, except that in Example 2, Co, Cr, Fe and Ni elemental powders with equal atomic ratio (25.00 at%) are used to prepare a mixed powder, and a CoCrFeNi coating is prepared under the same process conditions as in Example 1.

[0062] The rest is the same as in Example 1, and will not be described again here.

[0063] Example 3

[0064] Example 3 is basically the same as Example 1, except that:

[0065] In step (3), 16.39 at% of Al elemental powder, 16.39 at% of Co elemental powder, 16.39 at% of Cr elemental powder, 16.39 at% of Fe elemental powder, and 34.43 at% of Ni elemental powder are mixed to form a mixed powder to obtain AlCoCrFeNi. 2.1 Coating; and, step (3) cladding AlCoCrFeNi 2.1 The laser power for the coating is 300 W.

[0066] The rest is the same as in Example 1, and will not be described again here.

[0067] Example 4

[0068] Example 4 is basically the same as Example 1, except that the elemental composition of the aluminum bronze alloy powder used in Example 4 is: the mass percentage of copper is 82.0 at% and the mass percentage of aluminum is 18.0 at%.

[0069] The rest is the same as in Example 1, and will not be described again here.

[0070] Example 5

[0071] Example 5 is basically the same as Example 1, except that the elemental composition of the aluminum bronze alloy powder used in Example 5 is: the mass percentage of copper is 79.25 at and the mass percentage of aluminum is 20.75 at.

[0072] The rest is the same as in Example 1, and will not be described again here.

[0073] Example 6

[0074] Example 6 is basically the same as Example 1, except that in step (2) of Example 6, the process conditions for cladding the aluminum bronze barrier layer include: under argon protection, a coaxial powder-feeding laser is used, the laser power is 400 W, the cladding scanning speed displacement is 17 mm / s, the overlap rate is 60%, the laser focal length is 20 mm, the powder feeding rate is 20 discs / min, the powder feeding gas and the cladding protective gas are both argon, and the gas flow rate is 15 L / min.

[0075] The rest is the same as in Example 1, and will not be described again here.

[0076] Example 7

[0077] Example 7 is basically the same as Example 1, except that the thickness of the aluminum bronze barrier layer formed in Example 7 is 600 μm. The rest is the same as in Example 1, and will not be described again here.

[0078] Example 8

[0079] Example 8 is basically the same as Example 1, except that the thickness of the aluminum bronze barrier layer formed in Example 8 is 670 μm. The rest is the same as in Example 1, and will not be described again here.

[0080] Comparative Example 1

[0081] The only difference between Comparative Example 1 and Example 1 is that no aluminum bronze barrier layer is formed; instead, the CoCrNi layer is directly clad onto the TC4 titanium alloy substrate.

[0082] The rest is the same as in Example 1, and will not be described again here.

[0083] Comparative Example 2

[0084] The only difference between Comparative Example 1 and Example 2 is that no aluminum bronze barrier layer is formed; instead, the CoCrFeNi layer is directly clad onto the TC4 titanium alloy substrate.

[0085] The rest is the same as in Example 1, and will not be described again here.

[0086] Comparative Example 3

[0087] The only difference between Comparative Example 3 and Example 3 is that no aluminum bronze barrier layer is formed; AlCoCrFeNi is directly clad onto a TC4 titanium alloy substrate. 2.1 layer.

[0088] The rest is the same as in Example 1, and will not be described again here.

[0089] Comparative Example 4

[0090] The only difference between Comparative Example 4 and Example 2 is that a pure copper layer is used instead of the aluminum bronze barrier layer. Specifically, a pure copper layer (with the same thickness as the aluminum bronze barrier layer in Example 1) is clad onto a TC4 titanium alloy substrate, and then a CoCrFeNi layer is formed on the pure copper layer. The rest of the implementation is the same as in Example 1, and will not be repeated here.

[0091] Figure 1a These are electron microscope comparison images of the titanium alloy-based composite coating structures prepared in Example 1 and Comparative Example 1; Figure 1b These are electron microscope comparison images of the titanium alloy-based composite coating structures prepared in Example 2 and Comparative Example 2; Figure 1c These are electron microscope (EM) comparison images of the titanium alloy-based composite coating structures prepared in Example 3 and Comparative Example 3. Figure 1a , Figure 1b , Figure 1c As shown, compared with Comparative Examples 1-3, Examples 1-3 all achieved good bonding performance after using the aluminum bronze barrier layer, and no obvious cracks were observed in the surface coating and the aluminum bronze barrier layer.

[0092] The coatings obtained by cladding in the above examples and comparative examples were subjected to non-destructive testing using DPT-8 metal surface color penetrant testing agent. Figure 2 These are macroscopic morphological comparison images of the coatings obtained by cladding in Examples 1-3 and Comparative Examples 1-3. In these images, the red lines on the sample surface after non-destructive testing represent cracks. Figure 2As shown, the coating surface of Comparative Examples 1-3 has a large number of interwoven red cracks, some of which extend in a network pattern and penetrate between multiple cladding channels, indicating that there are large residual stress and brittle phase concentration areas inside the coating, leading to severe cracking. In Examples 1-3, due to the presence of an aluminum bronze barrier layer, the excessive dilution of Ti elements in the titanium alloy substrate into the wear-resistant layer was effectively suppressed, significantly reducing the formation of hard and brittle phases, and alleviating the concentration of interfacial thermal stress. Therefore, the overall crack resistance of the coating was significantly improved.

[0093] Figure 3 These are electron microscope comparison images of the cross sections of the titanium alloy-based composite coating structures prepared in Example 2 and Comparative Example 4. It can be seen that the aluminum bronze transition layer in Example 2 has no obvious cracks, while the pure copper layer in Comparative Example 4 has obvious cracks.

[0094] Figure 4 , Figure 5 and Figure 6 The images shown in order are EDS analysis diagrams of the cross sections of the titanium alloy-based composite coating structures of Comparative Example 2 (without a barrier layer), Comparative Example 4 (pure copper layer), and Example 2.

[0095] XRD diffraction tests were performed on the titanium alloy-based composite coating structures in Examples 1-3, with radial scanning at a scattering angle of 2θ from 20° to 90° and a scanning speed of 4° / min. Figure 7 These are the XRD patterns of the Ni-based multi-principal-element alloy layers from Examples 1-3. Figure 8 These are the XRD patterns of the aluminum bronze barrier layer in Example 2 and the pure copper layer in Comparative Example 4. Figure 8 As can be seen, compared to the pure copper layer, the aluminum bronze barrier layer in Example 2 has a simpler crystal structure, with only Cu phase (volume fraction of 44.65%) and Cu2TiAl phase (volume fraction of 55.35%), both of which are FCC structures, exhibiting good deformability and providing better mitigation of thermal stress during the cladding process. In contrast, when a pure copper layer was used as the intermediate transition layer in Comparative Example 2, many types of compounds were generated between Cu and Ti, leading to cracking at the Cu-Ti interface. The use of the aluminum bronze barrier layer suppressed the formation of various complex compounds, significantly reducing the cracking sensitivity of the Cu-Ti interface.

[0096] Figure 9 This is a comparison of the hardness distribution of the cross-sections of the titanium alloy-based composite coating structures in Example 2 (corresponding to "Cu-Al" in the figure) and Comparative Example 4 (corresponding to "Cu" in the figure). Figure 9It can be seen that the hardness of Example 2, after using the aluminum bronze barrier layer, remained generally between approximately 350–380 HV0.3, with minimal fluctuations and a continuous, smooth gradient transition; while Comparative Example 4 exhibited significant fluctuations, a wide range of hardness variations, and poor structural stability. Therefore, the aluminum bronze barrier layer effectively alleviated stress concentration, thereby significantly improving the crack resistance and structural reliability of the coating system.

[0097] Using an electrochemical workstation, the electrochemical performance of the titanium alloy-based composite coating structure prepared above was tested with 3.5 wt% NaCl solution as the corrosion medium. The test results are shown in Table 1.

[0098] Table 1

[0099] Group Corrosion potential (mV vs. Ag / AgCl) Corrosion current density (A / cm 2 ) Example 1 -277.80 5.97 x 10 -8 ]] Example 2 -315.50 2.01 x 10 -8 ]]> Example 3 -323.10 8.26 x 10 -7 ]]>

[0100] Figure 10 The image shows the measured potentiodynamic polarization curves of the titanium alloy-based composite coating structures in Examples 1-3. (Refer to Table 1 and...) Figure 10 As shown, the three coatings prepared using aluminum bronze barrier layers not only achieved crack-free preparation of titanium alloy surfaces, but also exhibited excellent electrochemical performance. The corrosion potentials (E0) of the three embodiments were [not specified]. corr All are located in a relatively positive potential range, and the corrosion current density (I) is... corr The low level indicates that it has a low corrosion rate and good corrosion resistance in corrosive media. The effects of Examples 4-8 are basically equivalent to those of Example 1. However, the coatings of Comparative Examples 1-3 could not be subjected to electrochemical testing due to severe cracking.

[0101] The abrasion resistance of the abrasion-resistant gradient coatings in Examples 1-3 was tested using a corrosion abrasion tester. The friction mode was reciprocating friction, the load was 10 N, the friction frequency was 2 Hz, the friction time was 0.5 h, and the corrosive medium was 3.5 wt% NaCl solution. Figure 11 The friction coefficient diagrams are for the titanium alloy-based composite coating structures in Examples 1-3. Figure 12 This is a wear rate calculation diagram for the titanium alloy-based composite coating structure in Examples 1-3. (Combined with...) Figure 11 , Figure 12 As shown, Examples 1-3 all exhibited relatively stable friction behavior under the corrosion-wear coupling environment, and showed the lowest friction coefficient and wear rate in the 3.5 wt% NaCl solution environment. This further proves that the present invention can significantly improve the service performance of titanium alloy-based composite coatings in complex working conditions such as marine environments through gradient structure design and aluminum bronze barrier layer control.

[0102] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0103] In summary, the solution provided by this invention effectively reduces the upward dilution of Ti elements during the subsequent preparation of the wear-resistant layer by forming an aluminum bronze barrier layer on a titanium alloy substrate, thus avoiding the formation of a large number of hard and brittle phases in the wear-resistant layer. Simultaneously, the aluminum bronze barrier layer can also alleviate the differences in thermophysical properties between the wear-resistant layer (such as a Ni-based multi-principal element wear-resistant layer) and the titanium alloy substrate, further improving the cracking problem. Therefore, the formed wear-resistant layer has a uniform and dense structure with almost no cracks; the substrate, the aluminum bronze barrier layer, and the wear-resistant layer exhibit good bonding strength and toughness, and possess excellent wear and corrosion resistance, contributing to improved wear and corrosion resistance of the titanium alloy surface in seawater environments.

[0104] All aspects, embodiments, features, and examples of this invention should be considered illustrative and used to explain and illustrate the invention, but not to limit the invention. The scope of the invention is defined only by the claims.

[0105] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the described embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims.

Claims

1. A method for suppressing upward dilution of Ti during the cladding of a wear-resistant layer on a titanium alloy surface, characterized in that, include: An aluminum bronze barrier layer is formed on a titanium alloy substrate. The phase structure of the aluminum bronze barrier layer includes a Cu phase and a Cu2TiAl phase. Both the Cu phase and the Cu2TiAl phase have an FCC crystal structure. The Cu2TiAl phase is formed by the reaction of Ti element in the titanium alloy substrate with Cu and Al. The volume percentages of the Cu phase and the Cu2TiAl phase in the aluminum bronze barrier layer are 40%~45% and 55%~60%, respectively. A transition alloy wear-resistant layer is formed on a titanium alloy substrate with the aluminum bronze barrier layer using laser cladding technology.

2. The method according to claim 1, characterized in that: Based on the blocking effect of the aluminum bronze barrier layer, the Ti content in the transition alloy wear-resistant layer, which is derived from the upward dilution of Ti element from the titanium alloy substrate during the laser cladding process, is less than 3 at%. And / or, the Cu content in the transition alloy wear-resistant layer derived from the aluminum bronze barrier layer during laser cladding is less than 6 at%; And / or, the thickness of the aluminum bronze barrier layer is 600 μm to 670 μm; And / or, the phase structure of the aluminum bronze barrier layer consists of Cu phase and Cu2TiAl phase.

3. The method according to claim 1 or 2, characterized in that, A method for forming an aluminum bronze barrier layer on a titanium alloy substrate includes: using aluminum bronze powder to perform laser cladding on the titanium alloy substrate; wherein the aluminum bronze powder contains 78-82 at% copper and 18-22 at% aluminum.

4. The method according to claim 3, characterized in that, The specific process conditions for forming the aluminum bronze barrier layer include: vertical laser scanning, laser cladding power of 400W~600W, cladding scanning speed of 15mm / s~17mm / s, overlap rate of 50%~60%, laser focal length of 19mm~20mm, powder feeding rate of 15~20 trays / min; both powder feeding gas and cladding protective gas are inert atmospheres, and the gas flow rate is 12L / min~15L / min; And / or, the particle size of the aluminum bronze powder is 15 μm to 53 μm.

5. The method according to claim 1, characterized in that, The transition alloy wear-resistant layer is a Ni-based multi-principal element wear-resistant layer; And / or, the material of the transition alloy wear-resistant layer includes CoCrNi alloy, CoCrFeNi alloy, or AlCoCrFeNi alloy.

6. The method according to claim 1 or 5, characterized in that: The process conditions for forming the wear-resistant layer of the transition alloy using laser cladding technology include: vertical laser scanning, laser cladding power of 300W~400W, cladding scanning speed of 15mm / s~17mm / s, overlap rate of 50%~60%, laser focal length of 20mm~21mm, powder feeding rate of 20~25 trays / min, and both powder feeding gas and cladding protective gas are inert atmospheres with a gas flow rate of 12L / min~15L / min.

7. A titanium alloy-based composite coating structure, characterized in that, The composite coating structure comprises a titanium alloy substrate and an aluminum bronze barrier layer and a transition alloy wear-resistant layer sequentially formed on the titanium alloy substrate, wherein the titanium alloy substrate composite coating structure is obtained based on the method of any one of claims 1-6.

8. A titanium alloy-based composite coating structure, characterized in that, It includes a titanium alloy substrate and an aluminum bronze barrier layer and a transition alloy wear-resistant layer arranged sequentially in a direction away from the titanium alloy substrate; The phase structure of the aluminum bronze barrier layer includes a Cu phase and a Cu2TiAl phase, both of which are FCC crystal structures; the volume percentages of the Cu phase and Cu2TiAl phase in the aluminum bronze barrier layer are 40%~45% and 55%~60%, respectively.

9. The method for suppressing upward dilution of Ti during the cladding of a wear-resistant layer on a titanium alloy surface, as described in any one of claims 1-6, is used in the preparation of wear-resistant moving parts.

10. A wear-resistant moving part, characterized in that, Includes the titanium alloy-based composite coating structure as described in any one of claims 7-8.

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