Hot isostatic pressing forming die for titanium-based composite material component and forming method of hot isostatic pressing forming die

Abstract

The invention provides a titanium-based composite material component hot isostatic pressing forming die and a forming method thereof.The forming die comprises a bottom plate and a forming sheath arranged on the bottom plate in a covering mode, the bottom plate and the forming sheath are connected in a sealed mode, a forming cavity is formed between the bottom plate and the forming sheath, and the forming cavity is communicated with the forming sheath. A discharging hole to be sealed is formed in the forming sheath; and the shape control piece is arranged in the forming cavity, the shape control piece comprises a base body part and a mold core part protruding out of the base body part, an isolation layer is arranged on the outer layer of the mold core part, and the base body part is fixedly arranged on the bottom plate through a fixing piece. The forming method comprises the steps that S1, a forming mold is designed and prepared; s2, preparing raw materials of the composite material; s3, raw material powder filling; s4, hot isostatic pressing processing; and S5, the mold is removed. In this way, pre-control forming of the titanium-based composite material component can be achieved, the working efficiency is improved, and raw materials are saved.

Description

Technical Field

[0001] The present invention relates to the field of core mold structures, and in particular to a hot isostatic pressing mold for titanium matrix composite components and a forming method thereof. Background Art

[0002] Titanium matrix composites have excellent properties such as high specific strength and high temperature resistance, and are an important part of future aerospace structural materials. However, titanium matrix composites have high costs and are difficult to process. The method of near-net shape preparation by hot isostatic pressing can reduce the subsequent machining allowance, save materials, and thus reduce costs.

[0003] However, at present, hot isostatic pressing of titanium matrix composites can only be used to prepare billets with regular shapes, and then components with a certain shape are prepared by a large range of machining. Especially in the aerospace field, there is a great demand for thick titanium matrix composite plates (plate thickness > 5 mm) with a large area of hollow structure. If the direct machining preparation method is used, a large amount of materials need to be consumed, resulting in an increase in material costs, and the subsequent machining of the hollow structure is difficult, the machining cycle is long, and the work efficiency is low.

[0004] The molds used for hot isostatic pressing of titanium alloys are usually steel, and the pressing temperature is lower than 1000 °C. However, titanium matrix composites often require more than 1100 °C to achieve the in-situ self-reaction of the reinforcing phase and reach a dense structure. However, above 1086 °C, iron and titanium will undergo a eutectic reaction to generate a liquid phase, posing a great danger to production. If titanium is used as the forming mold for titanium matrix composites, the homogeneous core of titanium is difficult to remove, and subsequent wire cutting and hollowing are required, resulting in low work efficiency. If ceramics are selected as the forming mold for titanium matrix composites, on the one hand, the position of the ceramics is not easy to fix, and on the other hand, under the high temperature action of hot isostatic pressing of titanium matrix composites, the ceramics are easily diffusion-bonded to titanium. Summary of the Invention

[0005] To solve the above problems, the present invention proposes a hot isostatic pressing mold for titanium matrix composite components with a simple structure and a forming method thereof.

[0006] The main content of the present invention includes: The present invention discloses a hot isostatic pressing mold for titanium matrix composites, including a bottom plate (1) and a forming sleeve (2) covering the bottom plate (1). The bottom plate (1) and the forming sleeve (2) are hermetically connected. A forming cavity is formed between the bottom plate (1) and the forming sleeve (2). The forming sleeve has a feeding hole (21) to be sealed, for filling titanium matrix composite powder into the forming cavity. A control member (3) is placed in the forming cavity. The control member (3) includes a base portion (31) and a core portion (32) protruding from the base portion (31). The core portion (32) is arranged to be in imitation of the hollow structure of the titanium matrix composite component. An isolation layer (33) is provided on the outer layer of the core portion (32). The base portion (31) is fixed to the bottom plate (1) through a fixing member (4).

[0007] Preferably, the fixing member includes a fixing substrate and a locking bolt. The fixing substrate includes a pressing portion pressing on the base portion. A connecting portion is circumferentially provided on the pressing portion. A profiling avoidance portion corresponding to the core portion is provided on the pressing portion. When the pressing portion presses on the base portion, the connecting portion is placed on the bottom plate, and the locking bolt connects the connecting portion and the bottom plate.

[0008] Preferably, the profiling avoidance portion is arranged as a hole structure.

[0009] Preferably, the core portion includes a plurality of cores arranged at intervals, and a plurality of holes are correspondingly arranged at intervals in the profiling avoidance portion.

[0010] Preferably, the upper end surface of the bottom plate has a lower groove, and the lower groove is arranged to be in imitation of the base portion. When the fixing substrate is arranged on the bottom plate, a receiving interval is formed between the lower groove and the fixing substrate, and the base portion is restricted within this receiving interval.

[0011] Preferably, the lower end surface of the pressing portion has an upper groove, and the upper groove is arranged to be in imitation of the base portion. When the fixing substrate is arranged on the bottom plate, the lower groove and the upper groove cooperate with each other to form a receiving interval, and the base portion is restricted within this receiving interval.

[0012] Preferably, the base portion and the core portion are integrally formed and made of ceramic material.

[0013] Preferably, the isolation layer is made of boron nitride material.

[0014] Preferably, the bottom plate, the forming jacket and the fixing member are all made of titanium material.

[0015] Also disclosed is a hot isostatic pressing forming method for a titanium matrix composite component, which adopts the above-mentioned hot isostatic pressing forming die and includes the following steps: S1. Design and preparation of the forming die: According to the shape of the hollow structure of the target titanium matrix composite component, design the shape of the core portion on the control member, and prepare the die based on the design. S2. Preparation of composite material raw materials: Select titanium alloy powder with a large particle size (<250μm is sufficient) and reinforcing phase powder. The reinforcing phase powder includes TiB. 2, BN, graphite, ZrB 2 , Si, La 2 O 3 , LaB 6 , Y 2 O 3 a mixture of one or more of the above, and the titanium alloy powder is a mixture of one or more of TC4, TA15, Ti55, and Ti65. Through the method of ball milling and mixing powders, a mixed powder of titanium alloy - reinforcing phase raw materials is obtained; S3. Loading of the mixed powder of raw materials: The mixed powder obtained in step S2 is loaded into the forming jacket from the discharge hole, compacted, degassed, and the discharge hole is sealed by welding to obtain a sealed mold; S4. Hot isostatic pressing process: First, raise the hot isostatic pressing temperature to 880 °C, then start applying pressure. The final pressure design range is 120 - 150 MPa, the holding time is 2 h - 6 h, and the temperature design range is 1200 - 1400 °C; S5. Removal of the mold: For the pressed mold with a fixed outer surface shape, the jacket and the bottom plate are removed by machining, and then the ceramic core part is broken to obtain the component.

[0016] The beneficial effects of the present invention are as follows: The shaping part is fixedly arranged in the forming cavity through the fixing part to maintain the stability of the shaping part during the hot isostatic pressing process. Then, through the shaping part, pre - controlled forming is carried out for the preparation of the titanium - based composite component by hot isostatic pressing, which can effectively save the raw materials of the component and reduce the raw material cost; The shaping part includes a core part made of ceramic. By breaking the core part, the separation between the finished component and the shaping part can be realized. The separation process is simple and the work efficiency is effectively improved; An isolation layer is arranged outside the core part. The isolation layer can isolate the core part from the material powder, prevent the reaction between the core part and the material powder during the hot isostatic pressing process, and at the same time assist in the separation between the core part and the finished component; During the hot isostatic pressing process, first raise the hot isostatic pressing temperature to 880 °C, so that during the heating process, the mixed powder can be fully softened, and the position in contact with the ceramic core part will be fully fitted. At this time, start applying pressure, and the powder can be effectively deformed and densified, effectively improving the quality of the finished component. Description of the Drawings

[0017] Figure 1 It is a three - dimensional structure schematic diagram of a preferred embodiment of the forming mold; Figure 2 It is an exploded structure schematic diagram of a preferred embodiment of the forming mold; Figure 3 It is a cross - sectional structure schematic diagram of a preferred embodiment of the forming mold; Figure 4 It is a flow chart of the hot isostatic pressing forming method; Figure 5 It is a process curve diagram of the hot isostatic pressing process; Reference numerals: 1. Bottom plate; 11. Lower groove 2. Forming sleeve; 21. Feeding hole 3. Shape control part; 31. Substrate part; 32. Core part; 33. Isolation layer 4. Fixing part; 41. Fixing substrate; 411. Lower pressing part; 412. Profiled avoiding part; 413. Connecting part; 42. Locking bolt 5. Titanium matrix composite component Specific implementation mode

[0018] The following specifically describes the technical solution protected by the present invention in conjunction with the accompanying drawings.

[0019] As Figures 1-3 shown, the present application provides a hot isostatic pressing forming die for a titanium matrix composite component, which includes a bottom plate 1 and a forming sleeve 2 covering the bottom plate 1. The bottom plate 1 and the forming sleeve 2 are hermetically connected, and the hermetic connection can be achieved by welding. Of course, if there are other methods, other methods can also be used. A forming cavity is formed between the bottom plate 1 and the forming sleeve 2. The forming sleeve 2 has a feeding hole 21 to be sealed. Titanium matrix composite powder is filled into the forming cavity through the feeding hole 21. After the titanium matrix composite is filled, the forming cavity is evacuated through the feeding hole 21, and is sealed after evacuation to ensure that the forming cavity is always in a sealed state during the hot isostatic pressing process. The sealing can be achieved by using a seal or by welding. To ensure the integrity of the forming sleeve 2, welding is preferably used.

[0020] As Figures 1-3 shown, a shape control part 3 for controlling the position and shape of the core of the titanium matrix composite component 5 is arranged in the forming cavity. The shape control part 3 is fixed to the bottom plate 1 through a fixing part 4 to ensure the stability of the position of the shape control part 3 during the hot isostatic pressing process. When the titanium matrix composite powder is densely formed in the forming cavity, its complex shape can be pre-controlled and formed through the shape control part 3.

[0021] As Figures 1-3As shown in the figure, the shaping control part 3 includes a base part 31 and a core part 32 protruding from the base part 31. An isolation layer 33 is provided on the outer layer of the core part 32. The base part 31 and the core part 32 are integrally formed. The base part 31 is used to stabilize the placement position of the shaping control part 3. The shape of the core part 32 is designed according to the hollow structure shape of the target titanium matrix composite component to control the shape of the finished component. In a specific embodiment, both the base part 31 and the core part 32 are made of ceramic material, so that after the component is formed, the shaping control part 3 can be directly broken to realize the separation between the core part 32 and the finished component. The separation process is simple and the operation is convenient. The isolation layer 33 is used to separate the ceramic material of the core part 32 from the titanium matrix composite material of the component. Its thickness range is controlled at 5 - 500 μm, which can prevent the ceramic from diffusing and bonding with titanium under the high temperature of hot isostatic pressing and realize the easy removal of the core part 32. In one embodiment, the isolation layer 33 can be made of boron nitride material. In the specific implementation process, the isolation layer 33 can be set on the outer layer of the core part 32 by brushing or spraying, and spraying is preferably used to improve the uniformity of the isolation layer 33.

[0022] As Figures 1-3 shown, the fixing part 4 includes a fixing base plate 41 for pressing the shaping control part 3 and a locking bolt 42 for connecting the fixing base plate 41 and the bottom plate 1. The fixing base plate 41 is fixedly connected to the bottom plate 1 through the locking bolt 42 to limit the shaping control part 3 between the fixing base plate 41 and the bottom plate 1, so that the shaping control part 3 is stable in the forming cavity. The fixing base plate 41 includes a pressing part 411 and a connecting part 413 arranged on the circumference of the pressing part 411. A profiling avoidance part 412 is provided at the position corresponding to the core part 32 on the pressing part 411. The profiling avoidance part 412 is set as a hole-like structure. When the pressing part 411 is pressed on the base part 31, the core part 32 correspondingly passes through the profiling avoidance part 412. The connecting part 413 is correspondingly placed on the bottom plate 1, and a number of threaded holes are provided on the connecting part 413. The locking bolt 42 is threadedly engaged in the threaded holes to be locked and connected to the bottom plate 1. Preferably, in this embodiment, the fixing base plate 42 is made of pure titanium material to ensure that the fixing base plate 41 will not react with the material powder during the hot isostatic pressing process, and during the separation of the finished product, it can be separated by simple machining and cutting.

[0023] Furthermore, in one embodiment, the core part 32 includes a number of cores arranged at intervals, and the profiling avoidance part 412 is correspondingly provided with a number of avoidance holes arranged at intervals. The avoidance holes correspond to the cores one by one, and the cores respectively pass through the avoidance holes.

[0024] As Figures 1-3As shown, further, in this embodiment, the upper end surface of the bottom plate 1 has a lower groove 11, and the lower groove 11 is arranged in imitation of the shape of the base portion 31, so that the base portion 31 can be placed in the lower groove 11 to ensure the accurate installation position of the profiling part. At the same time, the displacement of the base portion 31 in the horizontal direction is limited, and the fixing substrate 41 is pressed on the base portion 31 to limit the displacement of the base portion 31 in the vertical direction, so as to fix the profiling part 3 on the bottom plate 1.

[0025] As Figures 1-3 shown, further, in an embodiment, the depth of the lower groove 11 is equal to the thickness of the base portion 31 of the profiling part 3. The fixing substrate 41 is fixed on the bottom plate 1. A receiving interval is formed between the lower groove 11 and the pressing portion 411 of the fixing substrate 41, and the base portion 31 is restricted within this receiving interval to control the position of the profiling part 3. Further, in another embodiment, the depth of the lower groove 11 is less than the thickness of the base portion 31 of the profiling part 3. The bottom surface of the pressing portion 411 of the fixing substrate 41 is provided with an upper groove (not shown), and the upper groove can be arranged in imitation of the shape of the base portion 31. When the fixing substrate 41 is fixed on the bottom plate 1, the lower groove 11 and the upper groove cooperate with each other to form a receiving interval. At this time, the height of the receiving interval is equal to the thickness of the base portion 31, and the base portion is restricted within this receiving interval to control the position of the profiling part 3.

[0026] Working principle: First, according to the hollow shape of the target titanium matrix composite component, design the shape of the core part 32 on the profiling part and the shape of the profiling avoidance part 412 on the fixing substrate 41. The base portion 31 and the core part 32 of the profiling part 3 are machined from ceramics, the fixing substrate 41 is machined from titanium, and an isolation layer 33 is sprayed on the surface of the core part 32; then, the profiling part 3 is placed in the lower groove 11 on the bottom plate 1, and then the fixing substrate 41 is sleeved on the profiling part 3. The profiling avoidance part 412 of the fixing substrate 41 passes through the core part 32, the pressing portion 411 is pressed on the base portion 31, and the connecting portion 413 is placed on the bottom plate 1. The connecting portion 413 and the bottom plate 1 are locked by the locking bolt 42; then, the forming sleeve 2 is covered on the bottom plate 1, and the connection between the forming sleeve 2 and the bottom plate 1 is sealed and welded; then, the titanium matrix composite powder is filled into the forming cavity through the feeding hole 21. During filling, the vibration powder loading method is adopted, and then the inside of the forming cavity is evacuated, and the vacuum degree is less than 10 -3After Pa, the discharge hole 21 is sealed by welding to obtain a sealed mold. Then, the above mold together with the powder is put into a hot isostatic pressing furnace for hot isostatic pressing. After hot isostatic pressing, the powder will be connected to the shape control part 3, the fixed substrate 41, the bottom plate 1 and the forming sleeve 2 to form an integral green compact. After removing the forming sleeve, the fixed substrate and the bottom plate by machining, drilling is carried out at the core part by machining and the core part is broken, so that the component is separated from the core part. Finally, the component is appropriately modified and sandblasted on the inner surface of the component to obtain the target titanium matrix composite component.

[0027] Preferably, in this embodiment, the core part 32 is shaped by using a ceramic material. During separation, the core part 32 can be directly broken to realize the direct separation between the finished component and the shape control part 3. The separation process is simple and the operation is convenient. The finished component does not need to start wire cutting and hollowing processing from a blank with a regular shape, which can effectively save nearly 30% of the titanium matrix composite powder and effectively improve the working efficiency. The processing man-hours are reduced by 8 - 12 hours. An isolation layer 33 is arranged outside the core part 32, which effectively prevents the reaction between the core part 32 and the material powder during the hot isostatic pressing process and helps the separation between the core part 32 and the finished component.

[0028] A hot isostatic pressing forming method for a titanium matrix composite component adopts the above-mentioned hot isostatic pressing forming mold for a titanium matrix composite component, as Figures 1-5 shown, and includes the following steps: S1. Forming mold design: According to the hollow structure shape of the target titanium matrix composite component, design the shape of the core part on the shape control part and the shape of the profiling avoidance part on the fixed substrate, and prepare the mold based on the design; S2. Preparation of composite material raw materials: Select titanium alloy powder with a large particle size (<250μm is fine) and reinforcing phase powder. The reinforcing phase powder includes one or a mixture of several of TiB 2 , BN, graphite, ZrB 2 , Si, La 2 O 3 , LaB 6 , Y 2 O 3 . The titanium alloy powder is one or a mixture of several of TC4, TA15, Ti55, Ti65. Through the method of ball milling and mixing powders, a titanium alloy - reinforcing phase raw material mixed powder is obtained; S3. Loading of raw material powder: The mixed powder obtained in step S2 is filled into the forming sleeve from the discharge hole, vibrated, degassed, and the discharge hole is sealed by welding to obtain a sealed mold; S4. Hot isostatic pressing: First, raise the hot isostatic pressing temperature to 880 °C, then start applying pressure. The final pressure is designed to be in the range of 120 - 150 MPa, and the holding time is 2 h - 6 h to ensure sufficient densification; the temperature is designed to be in the range of 1200 - 1400 °C to ensure sufficient reaction between the reinforcing phase raw material and the titanium alloy powder. S5. Remove the mold: For the pressed mold with a fixed outer surface shape, remove the jacket and the bottom plate by machining, and then break the ceramic core part to obtain the component.

[0029] Furthermore, in the conventional hot isostatic pressing process of simultaneous heating and pressurization in the prior art, for titanium matrix composites with a relatively high pressing temperature, when the temperature has not reached the yield point of the composite powder, the pressure is relatively large, which is likely to cause stress concentration at the tip and is not conducive to the size control of the hollow structure on the finished component. Therefore, in step S3, during the hot isostatic pressing process, the temperature needs to be first raised to 880 °C. The specific process schematic diagram is as Figure 5 shown. During the heating process, the mixed powder can be fully softened, and the position in contact with the ceramic core part will fit well. At this time, when pressure is applied, the powder can be effectively deformed and densified.

[0030] Furthermore, trim the component obtained in step S5, and sandblast the inner surface of its hollow structure to improve the accuracy of the final finished component.

[0031] The above are only embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A hot isostatic pressing die for titanium-based composite material components, characterized in that: Mainly include: A base plate (1) and a molding sleeve (2) disposed on the base plate (1), the base plate (1) and the molding sleeve (2) being sealed and connected, a molding cavity being formed between the base plate (1) and the molding sleeve (2), the molding sleeve being provided with a discharge hole (21) to be sealed, for filling titanium-based composite material powder into the molding cavity; A control piece (3) is placed in the molding cavity, the control piece (3) comprising a base portion (31) and a core portion (32) protruding from the base portion (31), the core portion (32) being arranged in a similar shape to the hollow structure of the titanium-based composite material component, an isolation layer (33) being arranged on the outer layer of the core portion (32), and the base portion (31) being fixed to the bottom plate (1) via a fixing piece (4).

2. The hot isostatic pressing die for titanium-based composite material components according to claim 1, characterized in that: The fixing member (4) comprises a fixing base plate (41) and a locking bolt (42); the fixing base plate (41) comprises a pressing portion (411) pressed onto the base portion (31); a connecting portion (413) is circumferentially arranged on the pressing portion (411); a contoured avoiding portion (412) is arranged on the pressing portion (411) corresponding to the core portion (32); when the pressing portion (411) is pressed onto the base portion (31), the connecting portion (413) is placed on the bottom plate (1); and the locking bolt (42) connects the connecting portion (413) and the bottom plate (1).

3. The hot isostatic pressing die for titanium-based composite material components according to claim 2, characterized in that: The contour-profiling avoidance portion (412) is configured as a hole-shaped structure, and the core portion (32) can pass through the contour-profiling avoidance portion (412).

4. The hot isostatic pressing die for titanium-based composite material components according to claim 3, characterized in that: The core portion (32) includes a plurality of cores arranged at intervals, and the contour avoidance portion (412) is provided with a plurality of holes opened at intervals.

5. The hot isostatic pressing die for titanium-based composite material components according to claim 2, characterized in that: The upper end surface of the bottom plate (1) has a lower groove (11), and the lower groove (11) is arranged in a contour with the base portion (31). When the fixed base plate (41) is arranged on the bottom plate (1), a receiving area is formed between the lower groove (11) and the fixed base plate (41), and the base portion (31) is confined within the receiving area.

6. The hot isostatic pressing die for titanium-based composite material components according to claim 5, characterized in that: The lower end surface of the pressing portion (411) has an upper groove, and the upper groove is arranged in a similar shape to the base portion (31). When the fixed base plate (41) is arranged on the bottom plate (1), the lower groove (11) and the upper groove cooperate with each other to form a receiving area, and the base portion (31) is confined within the receiving area.

7. The hot isostatic pressing die for titanium-based composite material components according to claim 1, characterized in that: The base part (31) and the core part (32) are integrally formed and made of ceramic material.

8. The hot isostatic pressing die for titanium-based composite material components according to claim 1, characterized in that: The isolation layer (33) is made of boron nitride.

9. The hot isostatic pressing die for titanium-based composite material components according to claim 1, characterized in that: The base plate (1), the forming sleeve (2) and the fixing member (4) are all made of titanium.

10. A method for forming a titanium-based composite material component, using the hot isostatic pressing mold for a titanium-based composite material component according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Design and preparation of forming mold: according to the hollow structure shape of the target titanium-based composite material component, the shape of the core part on the control part is designed, and the mold is prepared based on the design; S2. Preparation of raw materials for composite materials: select titanium alloy powder and reinforcing phase powder with large particle size (<250μm), the reinforcing phase powder includes one or a mixture of TiB2, BN, graphite, ZrB2, Si, La2O3, LaB6, Y2O3, and the titanium alloy powder is one or a mixture of TC4, TA15, Ti55, Ti65, and obtain titanium alloy-reinforcement phase raw material mixed powder by ball milling; S3, raw material mixed powder filling: the mixed powder obtained in step S2 is filled into the molding sleeve from the discharge hole, vibrated, degassed, and the discharge hole is sealed and welded to obtain a sealed mold; S4, hot isostatic pressing: first increase the hot isostatic pressing temperature to 880℃, then start to apply pressure, the final pressure design range is 120-150MPa, the holding time is 2h-6h, and the temperature design range is 1200-1400℃; S5. Removing the mold: After pressing, the outer surface shape of the mold is fixed, and the sleeve and the bottom plate are removed by machining, and then the ceramic core is broken to obtain the component.

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