Method for manufacturing (zrti)c reinforced titanium alloy composite gear

Abstract

The application relates to a preparation method of a (ZrTi)C reinforced titanium alloy composite gear, which comprises the following steps: melting and cladding a zirconium-titanium alloy coating on the side surface of a titanium alloy cylinder, then carrying out hot forging processing to form a gear blank with a required shape, then carrying out finish forging and solid solution treatment on the gear blank, placing the forged gear in a gas carburizing furnace to carry out carburizing by taking acetylene gas as a carbon source, forming a carbonized layer on the surface of the zirconium-titanium alloy cladding layer, obtaining a carbide-titanium alloy gear with a (ZrTi)C carburized layer and a zirconium-titanium alloy cladding layer as gear surfaces, carrying out cleaning and finishing treatment, polishing the gear surfaces, and obtaining the (ZrTi)C reinforced titanium alloy composite gear. The gear forms a layered gradient structure from outside to inside, i.e. a complex carbide layer, a zirconium-titanium cladding layer and a substrate. The complex carbide (ZrTi)C has a good bonding interface with the zirconium-titanium alloy cladding layer and the cladding layer and the substrate, and the stability of the titanium alloy gear in different working conditions is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of gear materials and relates to a preparation method of a (ZrTi)C reinforced titanium alloy composite gear. BACKGROUND

[0002] With the development of lightweight military electronic equipment, the weight reduction requirement of the servo transmission mechanism is also increasingly high. The titanium alloy gear can be used to replace the steel alloy gear to achieve a weight reduction of about 60%, effectively reduce the mass of the mechanical system and improve the performance and efficiency of the system. In terms of performance, the titanium alloy gear can meet the product index requirement, but the friction coefficient of the titanium alloy gear is relatively large (0.6-0.8), the gear transmission efficiency is low, the friction loss is large, and even the function is lost. Therefore, reducing the surface friction coefficient of the titanium alloy gear is an urgent problem to be solved in the application engineering of the titanium alloy gear.

[0003] The main strategy for reducing the surface friction coefficient of the titanium alloy gear is to prepare a composite material, that is, to add a layer of material with a low friction coefficient on the surface of the titanium alloy gear. For example, the Chinese patent with the publication number CN113981441B discloses a preparation method of a gear surface coating, which adopts an ultra-high-speed laser cladding method to form a surface iron-based coating on the surface of a nickel-based gear, greatly improving the wear resistance of the gear surface. The Chinese patent with the publication number CN116100267A discloses a preparation method of a lightweight wear-resistant titanium alloy gear, which clads an alloy steel coating on a titanium alloy gear blank and directly processes the cladding layer into a tooth surface, improving the wear resistance of the titanium alloy gear. The Chinese patent with the publication number CN114231898A discloses a method of depositing a carbon-based thin film on the tooth surface by magnetron sputtering to form a low-friction coefficient, wear-resistant carbon-based thin film modified layer on the surface of the titanium alloy gear. The Chinese patent with the publication number CN109295343A discloses cladding mixed powder (titanium powder, nickel powder, titanium carbide powder) on the surface of the titanium alloy gear to further prepare a hardening layer with good wear resistance and low friction coefficient on the surface of the gear.

[0004] As can be seen from the above, fabricating composite gears is a feasible method to reduce the coefficient of friction. However, for titanium alloy gears, the bonding force between the composite layer and the tooth surface (blank) must be considered; otherwise, the composite layer may experience interfacial cracking and peeling during service. For example, in the steel / iron-titanium composite process, the large difference in interfacial thermophysical properties and the easy formation of hard and brittle intermetallic compounds by metallurgical reactions make the composite layer extremely prone to cracking and failure. Although sputtering to prepare carbon-based thin films on the tooth surface can avoid the generation of brittle phases, the film and the substrate are mechanically bonded and easily detached, and the coating thickness is too thin for long-term service. Fusing a suitable mixed powder system onto the titanium alloy gear tooth surface can improve the wear resistance of the tooth surface, but powder cladding is prone to defects such as porosity and inclusions, resulting in poor composite layer density and greatly reducing the wear resistance of the tooth surface. How to reduce the coefficient of friction of the titanium alloy gear tooth surface while ensuring sufficient thickness and excellent interfacial bonding is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing (ZrTi)C reinforced titanium alloy composite gears, which solves the problems of high friction coefficient and poor interfacial bonding between the matrix and the composite layer in titanium alloy composite gears prepared by existing methods.

[0006] The technical solution adopted in this invention is a method for preparing (ZrTi)C reinforced titanium alloy composite gears, comprising the following steps:

[0007] Step 1: Remove the oxide layer on the surface of the titanium alloy cylinder with sandpaper, then immerse it in an ethanol solution for ultrasonic cleaning and dry it.

[0008] Step 2: Using an automatic wire feeding arc cladding equipment, a zirconium-titanium alloy coating is clad onto the side of the titanium alloy cylinder to obtain a titanium alloy preform. The thickness of the cladding layer exceeds the total tooth height of the titanium alloy tooth blank by 3mm to 5mm.

[0009] Step 3: Hot forging the titanium alloy preform at 800-880℃ to form a gear blank of the required shape;

[0010] Step 4: Precision forging the gear blank at 900-980℃, followed by solution treatment, to obtain the forged gear;

[0011] Step 5: Place the forged gear in a gas carburizing furnace and use acetylene gas as a carbon source for carburizing to form a carbide layer with a thickness of 100μm to 200μm on the surface of the zirconium-titanium alloy cladding layer, thus obtaining a carbide-titanium alloy gear with a (ZrTi)C carburized layer and a zirconium-titanium alloy cladding layer as the tooth surface.

[0012] Step 6: Clean and finish the carbide-titanium alloy gear, and polish the tooth surface to obtain the (ZrTi)C reinforced titanium alloy composite gear.

[0013] In step 2, the power of arc cladding is 10-18 kW, the arc column diameter is 3-7 mm, the feeding mode is lateral wire feeding, the wire material is pure zirconium wire or zirconium-titanium alloy wire, the wire diameter is 0.8 mm-4 mm, the wire feeding speed is 50-80 mm / s, the scanning speed is 20-50 mm / s, argon is used as the protective gas, and the protective gas flow is 25-35 SCFH.

[0014] The zirconium content in the zirconium-titanium alloy wire is greater than or equal to 40 wt.%.

[0015] In step 4, the solid solution treatment comprises the following steps: placing the gear blank after finish forging into an atmosphere heating furnace, increasing the furnace temperature to 680-880 DEG C, and then cooling to room temperature at a cooling rate of 80-120 DEG C / min.

[0016] In step 5, before placing the forged gear into the gas carburizing furnace, the non-tooth part is coated with anti-permeation paint for anti-permeation treatment, and after the coating material is dried for 20-24 h, the forged gear is placed into the gas carburizing furnace.

[0017] In step 5, acetylene gas is used as the carbon source for carburizing, the carburizing temperature is 850-1050 DEG C, the holding time is 1-6 h, the carbon potential is controlled to be 0.4-0.6 during the holding stage, and the heating rate is 5-10 DEG C / min.

[0018] In step 6, the gear tooth surface is polished to a surface roughness of Ra=0.020.

[0019] The titanium alloy cylindrical material is Ti6Al4V.

[0020] The titanium alloy preform gear blank is subjected to hot forging at 800-880 DEG C, and the forging ratio is 1.2-1.3.

[0021] The gear blank is subjected to finish forging at 900-980 DEG C, and the forging ratio is 1.1-1.2.

[0022] The beneficial effects of the present application are as follows:

[0023] (1) The composite wear-resistant layer is prepared on the surface of the titanium alloy gear by the arc cladding and gas carburizing methods, and a layered gradient structure of a complex carbide layer -> a zirconium-titanium cladding layer -> a substrate is formed from the outside to the inside, the complex carbide (ZrTi)C has a good bonding interface with the zirconium-titanium alloy cladding layer and the cladding layer and the substrate, and the stability of the titanium alloy gear in different working conditions is improved.

[0024] (2) Hot forging is used to form the gear. Compared with machined gears, the material streamline characteristics are greatly preserved. The presence of streamlines makes the internal grain arrangement of the gear more uniform. The crystal direction is consistent with the stress direction, which improves the toughness of the gear. In the temperature range of solution treatment, the cladding layer undergoes β phase transformation. Combined with rapid cooling treatment, the solid solution ratio of zirconium and titanium elements increases, which improves the preparation efficiency of the subsequent (ZrTi)C carburizing layer.

[0025] (3) The friction coefficient of the (ZrTi)C reinforced titanium alloy composite gear prepared by the present invention can be reduced to 0.08-0.1, which significantly improves the wear resistance of titanium alloy gears. The thickness of the carbide layer is 100-200μm, which meets the application requirements. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the internal structure of the (ZrTi)C reinforced titanium alloy composite gear in this invention;

[0027] Figure 2 This is a SEM image of the transition zone between the (ZrTi)C carburized layer and the zirconium-titanium alloy cladding layer in Example 2 of this invention;

[0028] Figure 3 This is a SEM image of the transition zone between the zirconium-titanium alloy cladding layer and the titanium alloy substrate in Embodiment 2 of the present invention.

[0029] In the figure, 1. Titanium alloy substrate, 2. Zirconium-titanium alloy cladding layer, 3. (ZrTi)C carburized layer. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0031] The method for preparing (ZrTi)C reinforced titanium alloy composite gears of the present invention includes the following steps:

[0032] Step 1: Remove the oxide layer on the surface of the Ti6Al4V titanium alloy cylinder with sandpaper, then immerse it in an ethanol solution for ultrasonic cleaning and dry it.

[0033] Step 2: Using an automatic wire feeding arc cladding device, a zirconium-titanium alloy coating is clad onto the side of the titanium alloy cylinder. The arc cladding power is 10-18kW, the arc column diameter is 3-7mm, and the wire is fed by a side feeding method. The wire material is pure zirconium wire or zirconium-titanium alloy wire, with a zirconium content ≥40wt.% in the zirconium-titanium alloy wire, a wire diameter of 0.8mm-4mm, a wire feeding speed of 50-80mm / s, a scanning speed of 20-50mm / s, and argon gas is used as the protective gas with a flow rate of 25-35SCFH. Finally, a titanium alloy prefabricated tooth blank is obtained, and the cladding layer thickness exceeds the total tooth height of the titanium alloy tooth blank by 3mm-5mm.

[0034] Step 3, the titanium alloy preform gear blank is placed into a heating furnace and heated to 800-880℃ for 1-2h, after the holding period, the preform gear blank is taken out and placed into a preliminary forging die, and hot forging is performed using a hydraulic machine, the forging ratio is controlled to be 1.2-1.3, and after forging, air cooling is performed to obtain a gear blank with a desired shape;

[0035] Step 4, the gear blank is heated to 900-980℃ for 1-2h, after the holding period, the gear blank is taken out and placed into a precision forging die, and hot forging is performed using a hydraulic machine, the forging ratio is controlled to be 1.1-1.2, and after forging, air cooling is performed to obtain a precision forged gear, and then solid solution treatment is performed, including placing the precision forged gear blank into an atmosphere heating furnace, raising the furnace temperature to 680-880℃, holding for 2h, and then cooling to room temperature at a cooling rate of 80-120℃ / min, thereby obtaining a forged gear;

[0036] Step 5, first, the non-toothed portion is coated with a barrier coating material to perform barrier coating treatment, the barrier coating material is AC100 water-soluble barrier coating material, after the coating material is air dried for 20-24h, the forged gear is placed into a gas carburizing furnace, and acetylene gas is used as the carbon source to perform carburizing, the carburizing temperature is 850-1050℃, the holding time is 1-6h, the carbon potential during the holding period is controlled to be 0.4-0.6, the temperature rising rate is 5-10℃ / min, and a carbonized layer with a thickness of 100-200μm is formed on the surface of the zirconium-titanium alloy cladding layer, thereby obtaining a carbide-titanium alloy gear with a (ZrTi)C carburized layer and a zirconium-titanium alloy cladding layer as the tooth surface;

[0037] Step 6, the carbide-titanium alloy gear is cleaned and finished, and the tooth surface is polished to a surface roughness of Ra=0.020, thereby obtaining a (ZrTi)C reinforced titanium alloy composite gear.

[0038] Referring to Figure 1 , the (ZrTi)C reinforced titanium alloy composite gear is composed of a titanium alloy base 1, a zirconium-titanium alloy cladding layer 2, and a (ZrTi)C carburized layer 3.

[0039] Example 1

[0040] A method for preparing a (ZrTi)C reinforced titanium alloy composite gear, including the following steps:

[0041] Step 1, a Ti6Al4V titanium alloy cylinder with a cross-sectional diameter of 20mm and a height of 10mm is selected as the base, the surface of the Ti6Al4V titanium alloy cylinder is polished to 1000 mesh using sandpaper to remove the surface oxide layer, and then the Ti6Al4V titanium alloy cylinder is placed into an ethanol solution and ultrasonically cleaned for 30min, and then dried;

[0042] Step 2, uniformly cladding zirconium-titanium alloy coating on the side of titanium alloy cylinder by using automatic wire-feeding arc cladding equipment, the power of arc cladding is 10 kW, the diameter of arc column is 3 mm, the feeding mode is lateral wire-feeding, the wire material is pure zirconium wire, the diameter of wire material is 0.8 mm, the wire-feeding speed is 50 mm / s, the scanning speed is 20 mm / s, argon is used as protective gas, the flow rate of protective gas is 25 SCFH, finally the titanium alloy preform tooth blank is obtained, the thickness of cladding layer on the surface of titanium alloy preform tooth blank exceeds the full tooth height of titanium alloy tooth blank by 3 mm.

[0043] Step 3, placing the titanium alloy preform tooth blank into a heating furnace and heating to 800℃ for 1 h, after the end of heat preservation, taking out and placing into an initial forging die to perform hot forging by using a hydraulic machine, the forging ratio is controlled between 1.2-1.3, after forging, air cooling, the gear blank body with required shape is obtained;

[0044] Step 4, heating the gear blank body to 900℃ for 1 h, after the end of heat preservation, taking out and placing into a precision forging die to perform hot forging by using a hydraulic machine, the forging ratio is controlled between 1.1-1.2, after forging, air cooling to obtain the precision forged gear, then performing solid solution treatment, including placing the precision forged gear blank body into an atmosphere heating furnace, increasing the furnace temperature to 880℃, heat preservation for 2 h, then cooling to room temperature at a cooling rate of 80℃ / min, the forged gear is obtained;

[0045] Step 5, first coating the non-tooth part with anti-seepage coating material to perform anti-seepage treatment, after the coating material is air dried for 20 h, then placing the forged gear into a gas carburizing furnace to perform carburizing by using acetylene gas as carbon source, increasing the furnace temperature to 850℃ at a rate of 8℃ / min, heat preservation for 1 h, the carbon potential is controlled at 0.4 during the heat preservation stage, the carbide-titanium alloy gear with (ZrTi)C carburized layer and zirconium-titanium alloy cladding layer as tooth surface is obtained;

[0046] Step 6, performing cleaning and finishing treatment on the carbide-titanium alloy gear, polishing the tooth surface to a surface roughness of Ra=0.020, the (ZrTi)C reinforced titanium alloy composite gear is obtained.

[0047] Observing the microstructure of the (ZrTi)C reinforced titanium alloy composite gear prepared in Example 1, the thickness of the zirconium-titanium alloy cladding layer on the surface of the titanium alloy substrate is about 8 mm, the thickness of the (ZrTi)C carburized layer on the surface of the cladding layer is about 100 μm, the mechanical property detection of the (ZrTi)C reinforced titanium alloy composite gear shows that the tooth surface friction coefficient is 0.1.

[0048] Example 2

[0049] A preparation method of a (ZrTi)C reinforced titanium alloy composite gear, comprising the following steps:

[0050] Step 1, a Ti6Al4V titanium alloy cylinder with a cross-sectional diameter of 40 mm and a height of 20 mm was selected as a substrate, and the surface of the Ti6Al4V titanium alloy cylinder was polished to 1000 mesh by sandpaper to remove the surface oxide layer, then the cylinder was ultrasonically cleaned in ethanol solution for 30 min and dried;

[0051] Step 2, a zirconium-titanium alloy coating was uniformly cladded on the side surface of the titanium alloy cylinder by using an automatic wire feeding arc cladding device, the power of arc cladding was 12 kW, the arc column diameter was 4 mm, the feeding mode was lateral wire feeding, the wire material was Zr50Ti50 wire with a diameter of 1 mm, the wire feeding speed was 55 mm / s, the scanning speed was 25 mm / s, argon was used as the protective gas, and the protective gas flow rate was 27 SCFH, finally a titanium alloy pre-tooth blank was obtained, and the thickness of the cladding layer on the surface of the titanium alloy pre-tooth blank exceeded the full tooth height of the titanium alloy tooth blank by 4 mm.

[0052] Step 3, the titanium alloy pre-tooth blank was heated to 820℃ in a heating furnace for 1.5 h, then taken out and placed in a preliminary forging die for hot forging using a hydraulic press, the forging ratio was controlled between 1.2-1.3, and the forged blank was air-cooled to obtain a gear blank with the required shape;

[0053] Step 4, the gear blank was heated to 920℃ and kept for 1.5 h, then taken out and placed in a precision forging die for hot forging using a hydraulic press, the forging ratio was controlled between 1.1-1.2, and the forged gear was air-cooled to obtain a precision forged gear, which was then subjected to solid solution treatment, including placing the precision forged gear blank in an atmosphere heating furnace, raising the furnace temperature to 850℃, keeping for 2 h, and then cooling to room temperature at a cooling rate of 90℃ / min, to obtain a forged gear;

[0054] Step 5, the non-tooth part was coated with a barrier coating to prevent permeation, and after the coating material was air-dried for 24 h, the forged gear was placed in a gas carburizing furnace and carburized using acetylene gas as the carbon source, the furnace temperature was raised to 900℃ at a rate of 8℃ / min, and kept for 2 h, and the carbon potential was controlled at 0.4 during the holding stage, to obtain a carbide-titanium alloy gear with a (ZrTi)C carburized layer and a zirconium-titanium alloy cladded layer as the tooth surface;

[0055] Step 6, the carbide-titanium alloy gear was cleaned and finished, and the tooth surface was polished to a surface roughness of Ra=0.020, to obtain a (ZrTi)C reinforced titanium alloy composite gear.

[0056] The microstructure of the (ZrTi)C reinforced titanium alloy composite gear prepared in Example 2 was observed, Figure 2 the SEM image of the transition zone between the (ZrTi)C carburized layer and the zirconium-titanium alloy cladded layer, Figure 3 the SEM image of the transition zone between the zirconium-titanium alloy cladded layer and the titanium alloy substrate, and Figure 2 andFigure 3 As can be seen, the (ZrTi)C reinforced titanium alloy composite gear prepared by the method has a dense structure, the zirconium-titanium alloy cladding layer and the titanium alloy substrate are well combined, a dense transition zone is formed between the (ZrTi)C carburized layer and the zirconium-titanium alloy cladding layer, and the interfacial bonding strength of the (ZrTi)C carburized layer and the zirconium-titanium alloy cladding layer is greatly improved. The thickness of the zirconium-titanium alloy cladding layer in the (ZrTi)C reinforced titanium alloy composite gear is about 12 mm, the thickness of the (ZrTi)C carburized layer is about 135 μm, and the tooth surface friction coefficient of the (ZrTi)C reinforced titanium alloy composite gear is 0.092 after mechanical property detection.

[0057] Example 3

[0058] A preparation method of a (ZrTi)C reinforced titanium alloy composite gear, comprising the following steps:

[0059] Step 1, a Ti6Al4V titanium alloy cylinder with a cross-sectional diameter of 60 mm and a height of 30 mm is selected as a substrate, the surface of the Ti6Al4V titanium alloy cylinder is polished to 1000 mesh by sandpaper in stages to remove the surface oxide layer, then the Ti6Al4V titanium alloy cylinder is ultrasonically cleaned in an ethanol solution for 30 min and then dried.

[0060] Step 2, a zirconium-titanium alloy coating is uniformly cladded on the side surface of the titanium alloy cylinder by using an automatic wire feeding arc cladding device, the power of the arc cladding is 14 kW, the arc column diameter is 5 mm, the feeding mode is a side feeding mode, the wire material is Zr60Ti40 wire, the wire diameter is 2 mm, the wire feeding speed is 60 mm / s, the scanning speed is 30 mm / s, argon is used as a protective gas, and the protective gas flow rate is 29 SCFH, and finally a titanium alloy preform gear blank is obtained, and the thickness of the surface cladding layer of the titanium alloy preform gear blank exceeds the full tooth height of the titanium alloy gear blank by 4 mm.

[0061] Step 3, the titanium alloy preform gear blank is heated to 840 ℃ in a heating furnace and kept for 1.2 h, and then taken out and placed in an initial forging die to perform hot forging by using a hydraulic machine, the forging ratio is controlled to be between 1.2 and 1.3, and the forged gear blank is air cooled after forging to obtain a gear blank body with a required shape;

[0062] Step 4, the gear blank body is heated to 940 ℃ and kept for 1.6 h, and then taken out and placed in a precision forging die to perform hot forging by using a hydraulic machine, the forging ratio is controlled to be between 1.1 and 1.2, and the precision forged gear is air cooled after forging, and then solid solution treatment is performed, including placing the precision forged gear blank in an atmosphere heating furnace, increasing the furnace temperature to 800 ℃, keeping for 2 h, and then cooling to room temperature at a cooling rate of 100 ℃ / min, to obtain a forged gear.

[0063] Step 5, first, the non-tooth part is coated with a barrier coating, and after the coating material is dried for 22 hours, the forged gear is placed in a gas carburizing furnace, acetylene gas is used as the carbon source, the furnace temperature is raised to 950℃ at a rate of 5℃ / min, and the temperature is maintained for 4 hours, and the carbon potential is controlled at 0.5, so that a carbide-titanium alloy gear with a (ZrTi)C carburized layer and a zirconium-titanium alloy cladding layer as the tooth surface is obtained;

[0064] Step 6, the carbide-titanium alloy gear is cleaned and finished, and the tooth surface is polished to a surface roughness of Ra=0.020, so that a (ZrTi)C reinforced titanium alloy composite gear is obtained.

[0065] Microstructure observation of the (ZrTi)C reinforced titanium alloy composite gear prepared in Example 3 shows that the zirconium-titanium alloy cladding layer and the titanium alloy substrate are well bonded, a dense transition zone is formed between the (ZrTi)C carburized layer and the zirconium-titanium alloy cladding layer, and the interfacial bonding strength of the (ZrTi)C carburized layer and the zirconium-titanium alloy cladding layer is improved. The thickness of the zirconium-titanium alloy cladding layer in the (ZrTi)C reinforced titanium alloy composite gear is about 14mm, and the thickness of the (ZrTi)C carburized layer is about 165μm. The mechanical property detection of the (ZrTi)C reinforced titanium alloy composite gear shows that the tooth surface friction coefficient is 0.09.

[0066] Example 4

[0067] A method for preparing a (ZrTi)C reinforced titanium alloy composite gear, comprising the following steps:

[0068] Step 1, a Ti6Al4V titanium alloy cylinder with a cross-sectional diameter of 80mm and a height of 40mm is selected as the substrate, the surface of the Ti6Al4V titanium alloy cylinder is polished to 1000 mesh by sandpaper to remove the oxide layer, then it is ultrasonically cleaned in ethanol solution for 30min and dried.

[0069] Step 2, an automatic wire feeding arc cladding device is used to uniformly cladding zirconium-titanium alloy coating on the side surface of the titanium alloy cylinder, the power of arc cladding is 16kW, the arc column diameter is 6mm, the side feeding mode is used for feeding, the wire material is Zr70Ti30 wire with a diameter of 3mm, the wire feeding speed is 65mm / s, the scanning speed is 35mm / s, argon is used as the protective gas, and the protective gas flow is 28SCFH. Finally, a titanium alloy preform gear blank is obtained, and the thickness of the surface cladding layer of the titanium alloy preform gear blank exceeds the full tooth height of the titanium alloy gear blank by 4mm.

[0070] Step 3, the titanium alloy preform gear blank is placed in a heating furnace and heated to 860℃ for 1.8h, then taken out and placed in an initial forging die for hot forging using a hydraulic press, the forging ratio is controlled between 1.2-1.3, and the forged gear blank is air cooled, so that a gear blank with the desired shape is obtained.

[0071] Step 4, the gear blank is heated to 960℃ for 1.8h, after the holding time, it is taken out and put into a precision forging die to be hot forged using a hydraulic machine, the forging ratio is controlled between 1.1-1.2, after forging, the gear is air cooled to obtain a precision forged gear, and then the precision forged gear is subjected to solid solution treatment, including putting the precision forged gear blank into an atmosphere heating furnace, raising the furnace temperature to 750℃, holding for 2h, and then cooling to room temperature at a cooling rate of 110℃ / min, to obtain a forged gear;

[0072] Step 5, first, the non-tooth part is coated with a barrier coating material for barrier coating treatment, after the coating material is air dried for 23h, the forged gear is placed in a gas carburizing furnace, and acetylene gas is used as the carbon source for carburizing, the furnace temperature is raised to 1000℃ at a rate of 9℃ / min, and held for 5h, and the carbon potential is controlled at 0.6 during the holding stage, to obtain a carbide-titanium alloy gear with a (ZrTi)C carburized layer and a zirconium-titanium alloy cladding layer as the tooth surface;

[0073] Step 6, the carbide-titanium alloy gear is subjected to cleaning and finishing treatment, and the tooth surface is polished to a surface roughness of Ra=0.020, to obtain a (ZrTi)C reinforced titanium alloy composite gear.

[0074] Microstructure observation of the (ZrTi)C reinforced titanium alloy composite gear prepared in Example 4 shows that the zirconium-titanium alloy cladding layer and the titanium alloy substrate are well bonded, a dense transition zone is formed between the (ZrTi)C carburized layer and the zirconium-titanium alloy cladding layer, which improves the interfacial bonding strength of the (ZrTi)C carburized layer and the zirconium-titanium alloy cladding layer, the thickness of the zirconium-titanium alloy cladding layer in the (ZrTi)C reinforced titanium alloy composite gear is about 16mm, and the thickness of the (ZrTi)C carburized layer is about 180μm, and the mechanical property detection of the (ZrTi)C reinforced titanium alloy composite gear shows that the tooth surface friction coefficient is 0.085.

[0075] Example 5

[0076] A preparation method of a (ZrTi)C reinforced titanium alloy composite gear, comprising the following steps:

[0077] Step 1, a Ti6Al4V titanium alloy cylinder with a cross-sectional diameter of 100mm and a height of 50mm is selected as the substrate, the surface of the Ti6Al4V titanium alloy cylinder is polished to 1000 mesh by sandpaper in stages to remove the oxide layer, and then the Ti6Al4V titanium alloy cylinder is ultrasonically cleaned in an ethanol solution for 30min and dried;

[0078] Step 2, using automatic wire feeding arc cladding equipment to uniformly cladding zirconium titanium alloy coating on the side of titanium alloy cylinder, the power of arc cladding is 18kW, the arc column diameter is 7mm, using lateral wire feeding mode to feed, the wire material is Zr80Ti20 wire, the wire diameter is 4mm, the wire feeding speed is 70mm / s, the scanning speed is 40mm / s, using argon as protection gas and plasma gas, the protection gas flow is 30SCFH, the plasma gas flow is 2.0SCFH, finally obtaining titanium alloy preform tooth blank, the thickness of the surface cladding layer of titanium alloy preform tooth blank exceeds the full tooth height of titanium alloy tooth blank by 5mm.

[0079] Step 3, placing the titanium alloy preform tooth blank into the heating furnace to heat to 880℃ for 2h, after the end of the heat preservation, taking out and placing into the initial forging die to use hydraulic press for hot forging, the forging ratio is controlled between 1.2-1.3, after forging, air cooling, obtaining the required shape gear blank;

[0080] Step 4, heating the gear blank to 980℃ for 2h, after the end of the heat preservation, taking out and placing into the precision forging die to use hydraulic press for hot forging, the forging ratio is controlled between 1.1-1.2, after forging, air cooling to obtain the precision forged gear, then solid solution treatment, including placing the precision forged gear blank into the atmosphere heating furnace, increasing the furnace temperature to 680℃, heat preservation for 2h, then cooling to room temperature at a cooling rate of 120℃ / min, obtaining the forged gear;

[0081] Step 5, first using anti-seepage coating to coat the non-tooth part for anti-seepage treatment, after the coating material is dry for 24h, then placing the forged gear into the gas carburizing furnace to use acetylene gas as carbon source for carburizing, increasing the furnace temperature to 1050℃ at a rate of 10℃ / min, heat preservation for 6h, the carbon potential is controlled at 0.6 during the heat preservation stage, obtaining the carbide-titanium alloy gear with (ZrTi)C carburized layer and zirconium titanium alloy cladding layer as the tooth surface;

[0082] Step 6, cleaning and finishing treatment of the carbide-titanium alloy gear, polishing the tooth surface to a surface roughness of Ra=0.020, obtaining the (ZrTi)C reinforced titanium alloy composite gear.

[0083] Microstructure observation of the (ZrTi)C reinforced titanium alloy composite gear prepared in Example 5 shows that the zirconium titanium alloy cladding layer and the titanium alloy substrate have good interface bonding, a dense transition zone is formed between the (ZrTi)C carburized layer and the zirconium titanium alloy cladding layer, improving the interface bonding strength of the (ZrTi)C carburized layer and the zirconium titanium alloy cladding layer, the thickness of the zirconium titanium alloy cladding layer in the (ZrTi)C reinforced titanium alloy composite gear is about 20mm, the thickness of the (ZrTi)C carburized layer is about 200μm, the mechanical property detection of the (ZrTi)C reinforced titanium alloy composite gear shows that the tooth surface friction coefficient is 0.08.

Claims

1. Method for the production of (ZrTi)C reinforced titanium alloy composite gears, characterized in that, The method comprises the following steps: Step 1, removing the oxide layer on the surface of the titanium alloy cylinder by sandpaper, then ultrasonic cleaning in ethanol solution and drying; Step 2, cladding a zirconium-titanium alloy layer on the side surface of the titanium alloy cylinder by using an automatic wire feeding electric arc cladding device to obtain a titanium alloy preform gear blank, and the thickness of the cladding layer is 3-5 mm more than the full tooth height of the titanium alloy gear blank; Step 3, hot forging the titanium alloy preform gear blank at 800-880 DEG C to form a gear blank body with a required shape; Step 4, precision forging the gear blank body at 900-980 DEG C, and then performing solid solution treatment to obtain a forged gear; The solid solution treatment comprises the following steps: placing the precision forged gear blank into an atmosphere heating furnace, increasing the furnace temperature to 680-880 DEG C, keeping the temperature for 2 hours, and then cooling to room temperature at a cooling rate of 80-120 DEG C / min; Step 5, placing the forged gear into a gas carburizing furnace, and using acetylene gas as a carbon source to perform carburizing to form a carbonized layer with a thickness of 100-200 microns on the surface of the zirconium-titanium alloy cladding layer, thereby obtaining a carbide-titanium alloy gear with a (ZrTi)C carburized layer and a zirconium-titanium alloy cladding layer as gear surfaces; Step 6, performing cleaning and finishing treatment on the carbide-titanium alloy gear, and polishing the gear surfaces, thereby obtaining a (ZrTi)C reinforced titanium alloy composite gear.

2. The method of making a (ZrTi)C reinforced titanium alloy composite gear according to claim 1, wherein, In step 2, the power of the electric arc cladding is 10-18 kW, the diameter of the electric arc column is 3-7 mm, the wire is fed in a lateral feeding mode, the wire is made of pure zirconium wire or zirconium-titanium alloy wire, the diameter of the wire is 0.8-4 mm, the wire feeding speed is 50-80 mm / s, the scanning speed is 20-50 mm / s, argon is used as a protective gas, and the flow rate of the protective gas is 25-35 SCFH.

3. The method of making a (ZrTi)C reinforced titanium alloy composite gear according to claim 2, wherein, The zirconium content in the zirconium-titanium alloy wire is greater than or equal to 40 wt.%.

4. The method of making a (ZrTi)C reinforced titanium alloy composite gear according to claim 3, wherein, In step 5, before placing the forged gear into the gas carburizing furnace, the non-tooth part is coated with a permeation-resistant coating to perform permeation-resistant treatment, and after the coating material is air-dried for 20-24 hours, the forged gear is placed into the gas carburizing furnace.

5. The method of making a (ZrTi)C reinforced titanium alloy composite gear according to claim 4, wherein, In step 5, acetylene gas is used as the carbon source for carburizing, the carburizing temperature is 850-1050 DEG C, the holding time is 1-6 hours, the carbon potential is controlled to be 0.4-0.6 during the holding stage, and the temperature increasing rate is 5-10 DEG C / min.

6. The method of making a (ZrTi)C reinforced titanium alloy composite gear according to claim 1, wherein, In step 6, the gear surfaces are polished to a surface roughness of Ra=0.

020.

7. The method of making a (ZrTi)C reinforced titanium alloy composite gear according to claim 1, wherein, The titanium alloy cylinder is made of Ti6Al4V.

8. The method of making a (ZrTi)C reinforced titanium alloy composite gear according to claim 1, wherein, The titanium alloy preform gear blank is hot forged at 800-880 DEG C, and the forging ratio is 1.2-1.

3.

9. The method of making a (ZrTi)C reinforced titanium alloy composite gear according to claim 8, wherein, The gear blank body is precision forged at 900-980 DEG C, and the forging ratio is 1.1-1.2.

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