Titanium alloy reinforced blade leading edge thermal creep and diffusion bonding composite manufacturing method

Abstract

A kind of composite manufacturing method of blade leading edge titanium alloy reinforcing edge hot creep and diffusion connection, titanium alloy reinforcing edge upper and lower thin-walled prefabricated parts are respectively prepared by the way of cutting plate material, titanium alloy reinforcing edge middle layer block prefabricated part is prepared by the way of cutting titanium alloy block material;After being assembled, the upper thin-walled prefabricated part, the core mold, the middle layer block prefabricated part and the lower thin-walled prefabricated part are arranged between the upper and lower molds, and the prefabricated part is bent and attached to the mold by cold pressing, and the titanium alloy reinforcing edge is obtained by composite forming after die closing.The composite method of hot creep and diffusion connection after piece cold pressing is used to process leading edge reinforcing edge once, which can significantly improve the forming efficiency and material utilization rate, shorten the processing cycle, and at the same time, the size precision and forming quality of reinforcing edge can be well controlled.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of an aero-engine, and particularly relates to a composite fan blade front edge titanium alloy reinforcing edge hot creep and diffusion bonding composite manufacturing method. BACKGROUND

[0002] In order to improve the fatigue resistance and impact resistance of an aero-engine blade, a titanium alloy reinforcing edge needs to be added to the front edge of a composite material blade, the reinforcing edge has a complex geometric configuration, the contour size is large, local features are many, curvature mutation is large, and the wall thickness is extremely thin, and the geometric shape and size precision of the reinforcing edge structure will have a significant influence on the aerodynamic performance, service life and reliability of the aerospace component. Meanwhile, the titanium alloy has large deformation resistance at normal temperature, serious springback and is prone to local fracture, which leads to great manufacturing difficulty of the component. A hot plastic forming process, such as hot press forming, hot calibration, high-temperature air inflation forming and the like, is usually used to process the composite fan blade front edge metal reinforcing edge. SUMMARY

[0003] The application aims at the problems that the existing technology uses hot creep forming to distribute the upper and lower thin-wall preforms of the reinforcing edge, the process flow is complex, the time consumption is long, the long-time high-temperature forming causes the titanium alloy material to have large grains, and the strength of the formed part is poor, and the round holes on the ear of the existing thin-wall preform are deformed or even torn in the hot creep forming process, which leads to the problem that the next diffusion bonding process cannot be accurately positioned, and proposes a composite manufacturing method of blade front edge titanium alloy reinforcing edge hot creep and diffusion bonding, which uses the composite method of cold-state compression after slicing and hot creep and diffusion bonding to process the front edge reinforcing edge once, can significantly improve the forming efficiency and material utilization rate, shorten the processing cycle, and well control the size precision and forming quality of the reinforcing edge.

[0004] The application is implemented by the following technical scheme:

[0005] The application relates to a composite manufacturing method of blade front edge titanium alloy reinforcing edge hot creep and diffusion bonding, upper and lower thin-wall preforms of the titanium alloy reinforcing edge are prepared by cutting a plate, and a middle layer block preform of the titanium alloy reinforcing edge is prepared by cutting a titanium alloy block; the upper thin-wall preform, a core mold, the middle layer block preform and the lower thin-wall preform are assembled and arranged between upper and lower molds, the preforms are bent and attached to the molds through cold-state compression, and the titanium alloy reinforcing edge is obtained through composite forming after mold closing.

[0006] The upper and lower thin-wall preforms and the middle layer block preform are all made of TC4 titanium alloy.

[0007] The core mold and the upper and lower molds are all made of 310S stainless steel.

[0008] The upper and lower thin-walled prefabricated parts are flat sheet structures, and their shapes are obtained by process unfolding of the upper and lower thin-walled structures after the reinforcing edges are split.

[0009] The upper and lower faces of the intermediate layer block prefabricated part are respectively matched with the upper and lower thin-walled prefabricated parts, and the inner side face of the intermediate layer block prefabricated part is matched with the front edge of the composite fan blade.

[0010] The outer shape face of the intermediate layer block prefabricated part meets the design requirements of the outer shape face of the reinforcing edge.

[0011] The upper and lower molds meet the design requirements of the outer shape face of the reinforcing edge, and are used for controlling the bending shape of the upper and lower thin-walled prefabricated parts in the thermal creep process and the forming precision of the outer shape face in the diffusion bonding process.

[0012] The outer circle of the upper and lower molds is provided with a threaded hole locking structure, and the upper and lower molds can be locked through bolts.

[0013] The outer circle of the upper and lower molds is provided with a positioning structure, and the positioning structure is a stepped through hole, which can position the upper and lower molds through a pin.

[0014] The outer surface of the core mold is matched with the inner cavity of the reinforcing edge, and is used for controlling the bending shape of the upper and lower thin-walled prefabricated parts in the thermal creep forming process and the forming precision of the inner cavity in the diffusion bonding process.

[0015] The assembly refers to that the positioning pin holes on the ear pieces extending outwards from the contact faces of the upper and lower thin-walled prefabricated parts and the intermediate layer block prefabricated part are connected to fix the core mold.

[0016] The ear piece specifically refers to the ear piece with a hole formed by extending outwards from the contact face of the prefabricated part and the core mold. After the assembly is completed, the holes on the ear pieces on both sides are in the same vertical position, and the positions of the prefabricated parts and the core mold are controlled.

[0017] The cold-state pressing refers to that after the prefabricated parts and the core mold are assembled, they are placed in the mold, and the mold is locked through the locking structure. In this process, the flat sheet prefabricated parts will be bent and matched with the mold and the core mold.

[0018] The composite forming refers to that the prefabricated parts are simultaneously subjected to thermal creep forming and diffusion bonding forming by heating to 900 DEG C and pressurizing to 2 MPa in a vacuum hot-pressing furnace for 60 min, and after the forming is completed, the product is cooled to room temperature in the furnace and then taken out.

[0019] The thermal creep forming is realized after the mold is pressed and the vacuum hot-pressing furnace is heated and kept for a period of time.

[0020] The diffusion link forming is realized by heating and pressurizing through a vacuum hot press furnace, and after completion, the temperature and pressure are maintained and the furnace is cooled, finally the core mold is taken out, the ear piece is cut and removed, and the titanium alloy reinforcing edge of the composite fan blade leading edge is obtained.

[0021] Technical effects

[0022] The present application adopts the method of thermal creep and diffusion bonding composite forming. In the forming process, the plane thin plate preform simultaneously occurs thermal creep forming and diffusion bonding behavior; by putting the preform into the mold and cold pressing, the upper and lower plane thin plate preforms are deformed to obtain a shape suitable for the reinforcing edge, and the forming process of the curved thin-walled structure is omitted; only one set of mold is used in the forming process, and only one thermal forming process is carried out, the vacuum heating furnace is not opened during the process, and the oxidation of the diffusion bonding interface is avoided. Not only the manufacturing cost of multiple heating and cooling is saved, the forming efficiency is improved to 3 times of the original, but also the titanium alloy grain coarsening is avoided, and the strength of the formed part is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The schematic view of the titanium alloy reinforcing edge of the composite fan blade leading edge of the embodiment is shown in the figure.

[0024] Figure 2 The schematic view of the upper and lower preforms of the titanium alloy reinforcing edge of the embodiment is shown in the figure.

[0025] Figure 3 The schematic view of the connection between the core mold and the preform of the embodiment is shown in the figure.

[0026] Figure 4 The assembly schematic view of the embodiment is shown in the figure.

[0027] Figure 5 The mold closing schematic view of the embodiment is shown in the figure.

[0028] Figure 6 The three-dimensional assembly schematic view of each part of the embodiment is shown in the figure.

[0029] In the figure: 1 titanium alloy reinforcing edge, 2 upper thin-walled preform, 3 lower thin-walled preform, 4 middle layer block preform, 5 core mold, 6 upper mold, 7 lower mold, 8 ear piece, 9 pin, 10 bolt. DETAILED DESCRIPTION

[0030] As Figure 1As shown, the present embodiment relates to a composite manufacturing method of blade leading edge titanium alloy reinforcing edge thermal creep and diffusion bonding, which adopts cold-state pressing of pieces, and obtains the titanium alloy reinforcing edge of the composite material fan blade leading edge of the aero-engine through thermal creep forming and diffusion bonding. The upper thin-walled preform 2 and the lower thin-walled preform 3 are processed by cutting titanium alloy sheet, and the middle layer block preform 4 is obtained by cutting titanium alloy block material. The upper thin-walled preform 2, the middle layer block preform 4 and the lower thin-walled preform 3 are pressed under cold state through the upper die 6, the lower die 7 and the core die 5, and the precision of the titanium alloy reinforcing edge is guaranteed by the profile of the upper die 6, the lower die 7 and the core die 5. Threaded holes are provided on the upper die 6 and the lower die 7, and the die is locked through threads. The core die 7 is fixed between the preforms through pins, and the formed part is obtained after thermal creep forming and diffusion bonding by controlling temperature, pressure and time. Finally, the connecting part is cut off to obtain the titanium alloy reinforcing edge 1, which specifically includes the following steps:

[0031] S1: Determine the geometric shape of the titanium alloy reinforcing edge 1. The reinforcing edge 1 is designed according to the contour of the composite material fan blade; the geometric shape of the upper thin-walled preform 2, the middle layer block preform 4 and the lower thin-walled preform 3 is divided by the shape of the titanium alloy reinforcing edge, wherein the upper thin-walled preform 2 and the lower thin-walled preform 3 are thin-walled parts obtained by process development from the thin-walled part of the titanium alloy reinforcing edge 1, and the shape of the middle block preform 4 is the remaining part after removing the thin wall. The contact surface of the preform extends outward to form a hole lug 8 for positioning between the preform and the core die 5.

[0032] S2: The upper thin-walled preform 2 and the lower thin-walled preform 3 are obtained by cutting sheet material, and the two blank parts are equal-thickness planar thin-walled parts; the titanium alloy block material is cut to obtain the middle layer block preform 4. The shape of the inner and outer surfaces of the three preforms and the surface roughness of each surface are controlled by cutting and polishing.

[0033] As shown in Figure 2 The upper and lower preforms of the titanium alloy reinforcing edge of the present embodiment are planar thin-walled structures, and their shapes are not directly the same as the curved surface structure of the formed part.

[0034] S3: Spray the contact surface of all parts that do not need to be connected with welding inhibitor, and assemble the lower die 7, the lower thin-walled preform 3, the core die 5, the middle layer block preform 4, the upper thin-walled preform 2 and the upper die 6 in sequence. The dies are connected and positioned by pins 9. The lugs of the preforms extend out of the diffusion bonding die, and the lugs 8 are connected with the core die 5 through the pins 9, thereby playing a positioning role on the preforms.

[0035] As shown in Figure 3As shown, the core mold is connected with the prefabricated part; the planar thin-walled prefabricated part is connected with the core mold through the pin under cold state. Due to the elastic bending of the planar structure, the prefabricated part is not completely attached to the core mold.

[0036] As shown, the prefabricated part and the matching structure of the core mold are put into the mold, and the planar thin-walled prefabricated part is deformed further through the compression of the mold, and is attached to the upper and lower molds and the core mold. Figure 4

[0037] S4: After all the assembly is completed, the upper and lower molds are locked by the bolt 10.

[0038] As shown, the mold is locked through the locking structure on the mold after the mold is closed, and the springback of the prefabricated part is prevented. Figure 5

[0039] S5: Before forming, the bolt 10 is removed, the vacuum degree of the vacuum hot-pressing furnace is extracted to 5x10 -3 Pa, the temperature is raised to 900℃, then the pressure is increased to 2MPa, and the temperature and pressure are maintained for 60min. The three-layer prefabricated part is compounded and formed. After the forming is completed, the diffusion connection product is cooled to room temperature with the furnace.

[0040] As shown, the assembly is matched from bottom to top, and is directly compressed under cold state, so that the upper and lower thin-walled prefabricated parts are elastically bent and deformed. Figure 6

[0041] S6: After the diffusion connection is completed, the formed part is taken out. The pin 9 on the lug 8 and the core mold 5 are removed, the lug 8 is removed by cutting, and the titanium alloy reinforcing edge 1 is obtained.

[0042] Through specific actual experiments, the composite forming is carried out at 2MPa, 910℃, and the temperature and pressure are maintained for 60min. The experimental data obtained is that the size precision of the formed part is high, the forming precision of the main forming area is within 0-0.05mm, the diffusion connection is good, the strength of the formed part is good, the tensile strength reaches more than 92% of the base material, and the material utilization rate is more than 60%.

[0043] ​​​In summary, the titanium alloy reinforcing edge is formed by the scheme of hot creep and diffusion bonding composite forming after the cold-state pressing of the titanium alloy reinforcing edge, and only simple cutting of the sheet material is needed to obtain the upper and lower prefabricated parts, so the process has low processing difficulty and high processing efficiency; the upper and lower plane sheet prefabricated parts are deformed by direct cold-state pressing to obtain a shape suitable for the reinforcing edge, and the forming process of the curved thin-walled structure is omitted; in the composite forming process, the titanium alloy material simultaneously performs hot creep forming and diffusion bonding forming under the set process parameters, the hot creep process eliminates the deformation stress of the titanium alloy, avoids the fracture of the titanium alloy under the diffusion bonding pressure, and also reduces the springback of the titanium alloy sheet, and the diffusion bonding process realizes the effective connection of the material interface; only one set of molds is used in the forming process of the application, which greatly saves the manufacturing cost; at the same time, only one hot forming process is performed, the vacuum heating furnace is not opened during the process, the oxidation of the diffusion bonding interface is avoided, not only the manufacturing cost of multiple heating and cooling is saved, but also the forming efficiency is improved to 3 times of the original, and the titanium alloy grain coarsening is also avoided, so that the strength of the formed part is greatly improved.

[0044] The above specific embodiments can be adjusted in different ways by those skilled in the art without departing from the principles and purposes of the application, the protection scope of the application is subject to the claims and is not limited by the above specific embodiments, and each implementation scheme within the scope is subject to the constraints of the application.

Claims

1. A composite manufacturing method for a titanium alloy reinforcing edge of a blade, involving thermal creep and diffusion bonding, characterized in that... The upper and lower thin-walled preforms with titanium alloy reinforcing edges are prepared by cutting sheet metal, and the middle layer block preform with titanium alloy reinforcing edges is prepared by cutting titanium alloy block material. The upper thin-walled preform, the core mold, the middle layer block preform, and the lower thin-walled preform are assembled and placed between the upper and lower molds. The preforms are bent and fitted to the molds by cold pressing. After mold closing, the titanium alloy reinforcing edges are obtained through composite forming. The upper and lower thin-walled prefabricated parts are planar thin-plate structures, and their shapes are obtained by unfolding the upper and lower thin-walled structures after the reinforcing edges are split. The assembly refers to the connection between the upper and lower thin-walled prefabricated parts, the intermediate layer block prefabricated parts, and the core mold through the positioning pin holes on the ear pieces extending outward from the contact surfaces, thereby fixing the core mold. Specifically, the ear pieces are: the contact surfaces of the prefabricated parts and the perforated ear pieces extending outward from the core mold. After the assembly is completed, the holes on the ear pieces on both sides are in the same vertical position, controlling the position of the prefabricated parts and the core mold. The aforementioned cold pressing refers to: at room temperature, assembling the preform and the core mold and placing it in the mold, locking it with the locking structure on the mold; through the cold pressing process, the flat thin plate preform will bend and fit into the mold and the core mold surface.

2. The composite manufacturing method of titanium alloy reinforcing edge of blade with thermal creep and diffusion bonding according to claim 1, characterized in that, The upper and lower thin-walled preforms and the intermediate layer block preforms are all made of TC4 titanium alloy; the core mold and the upper and lower molds are all made of 310S stainless steel.

3. The composite manufacturing method of titanium alloy reinforcing edge of blade with thermal creep and diffusion bonding according to claim 1, characterized in that, The upper and lower surfaces of the intermediate layer block prefabricated component are respectively bonded to the upper and lower thin-walled prefabricated components, and the inner surface of the intermediate layer block prefabricated component matches the leading edge of the composite fan blade.

4. The composite manufacturing method of titanium alloy reinforcing edge of blade with thermal creep and diffusion bonding according to claim 1, characterized in that, The outer rings of the upper and lower molds are provided with threaded hole locking structure and positioning structure. The upper and lower molds can be locked by bolts. The positioning structure is a through hole with steps, and the upper and lower molds can be positioned by pins.

5. The composite manufacturing method of titanium alloy reinforcing edge of blade with thermal creep and diffusion bonding according to claim 1, characterized in that, The outer surface of the core mold matches the inner cavity of the reinforcing edge to control the bending shape of the upper and lower thin-walled preforms during thermal creep forming, as well as the forming accuracy of the inner cavity during diffusion bonding.

6. The composite manufacturing method of titanium alloy reinforcing edge of blade with thermal creep and diffusion bonding according to claim 1, characterized in that, The aforementioned composite molding refers to heating the preform to 900°C and pressurizing it to 2MPa in a vacuum hot press furnace, holding it at the temperature and pressure for 60 minutes, so that the preform simultaneously achieves thermal creep forming and diffusion bonding forming. After the forming is completed, the product is cooled to room temperature with the furnace, and then the diffusion-bonded product is taken out.

7. The composite manufacturing method of titanium alloy reinforcing edge of blade with thermal creep and diffusion bonding according to claim 1, characterized in that, The aforementioned thermal creep forming is achieved by pressing the material into a mold, followed by heating it in a vacuum hot press furnace and holding it at that temperature for a period of time.

8. The composite manufacturing method of titanium alloy reinforcing edge of blade with thermal creep and diffusion bonding according to claim 1, characterized in that, The diffusion bonding forming is achieved by heating and pressurizing in a vacuum hot press furnace. After completion, the furnace is kept at a constant temperature and pressure and cooled. Finally, the core mold is removed, and the lugs are cut off to obtain the titanium alloy reinforcing edge of the leading edge of the composite material fan blade.

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