Near-net forming method for titanium alloy-based composite material powder component

Abstract

The invention discloses a near-net forming method for a titanium alloy-based composite material powder component, belongs to the technical field of thin-wall complex component manufacturing, and particularly aims at near-net forming of a high-temperature titanium alloy-based composite material thin-wall complex component. Aiming at a complex thin-wall titanium alloy cabin section structural component with the service temperature reaching 700-750 DEG C, the high-temperature titanium alloy-based thin-wall complex component is obtained through a proper TiB2 powder and Ti60 powder matching and uniform powder mixing process and through a sheath design, a hot isostatic pressing process and a sheath removal process. Through a titanium alloy-based composite material hot isostatic pressing near-net forming technology, tissue-performance integrated regulation and control are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of manufacturing thin-walled complex components, and in particular relates to a near-net-shape forming method for a titanium alloy-based composite material powder component. Background Art

[0002] High-temperature titanium alloys have excellent thermal strength and high specific strength. As a lightweight and high-strength structural material, they are particularly suitable for working in medium-temperature (350-600°C) environments. They are widely used in aerospace rudders, cabins, aircraft engine containment cases, integral blades and blades. At present, the highest operating temperature of high-temperature titanium alloys in the world is 600°C, including IMI834 in the UK, Ti1100 in the United States, BT36 in Russia and Ti60 in China. After 40 years of development, their operating temperatures have never been broken through. 600°C is also the "thermal barrier" temperature of high-temperature titanium alloys. With the development of a new generation of aerospace vehicles, the operating temperature of their hot end parts will reach 700-750°C, and traditional high-temperature titanium alloys will not meet the use requirements. High-temperature titanium alloys reinforced with ceramic particles, that is, high-temperature titanium alloy-based composite materials, have higher high-temperature strength, creep resistance, impact resistance and fatigue performance than the matrix, and are particularly suitable for extremely harsh working conditions in aerospace. They are considered to be a new generation of aviation and aerospace materials that can break through the thermal strength of existing high-temperature titanium alloys.

[0003] The target product is a high-temperature titanium alloy-based thin-walled cabin section structure with a diameter of Φ300-400mm and a height of 400-500mm. Its wall thickness is 3-5mm, and the inner profile has 4 annular ribs, 24 bosses and 4 side hole structures. The structure is complex. The traditional manufacturing idea is: casting → forging → machining → target product or casting → forging → ring rolling → machining → target product.

[0004] Traditional titanium-based composite materials are mainly prepared by ingot metallurgy, that is, the in-situ reaction of molten Ti with B4C, C, B, LaB6, Y, etc. generates ceramic particle reinforcement phases TiB, TiC and rare earth oxides La2O3, Y2O3, etc. However, the resulting cast titanium-based composite materials generally have poor plasticity and toughness, and there is also uneven composition. It is necessary to regulate the organization and improve the strength and plasticity through high-plasticity thermomechanical processing. Whisker-like TiB and granular TiC have a strong tendency to be brittle during the deformation process, and it is easy to produce hole defects, making the deformation process uncontrollable. The main difficulties of the above manufacturing scheme are that the titanium-based composite material has poor plasticity, is prone to cracking during forging, has a low yield, poor processability, and has a high processing cycle and cost. In addition, this method has a low material utilization rate, a complex internal cavity structure of the target product, and is difficult to machine and has a high cost. Summary of the invention

[0005] The purpose of the present invention is to provide a near-net-shape forming method for titanium alloy-based composite material powder components, combining specific materials with hot isostatic pressing technology to obtain high-temperature titanium alloy-based composite material components with excellent high-temperature performance.

[0006] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0007] A near-net-shape forming method for a titanium alloy-based composite material powder component comprises the following steps:

[0008] (1) A Ti60 alloy ingot is obtained by 2-3 consumable arc melting, a Φ20-100 mm forged rod is obtained by forging deformation, and Ti60 powder is prepared by atomization method;

[0009] (2) screening and removing impurities from the titanium alloy powder obtained in step (1) to obtain clean Ti60 powder;

[0010] (3) preparing TiB2 powder and Ti60 powder in proportion to ensure that the mass fraction of TiB generated after hot isostatic pressing is 4 to 10%;

[0011] (4) ball milling the TiB2 and Ti60 powders prepared in step (3) and mixing them under argon protection;

[0012] (5) Manufacturing and welding the sheath structure according to the shape of the target structural part;

[0013] (6) Filling the TiB2 and Ti60 mixed powder obtained in step (4) into the sheath structure obtained in step (5), compacting the powder, and welding and encapsulating the degassing pipe and the sheath;

[0014] (7) degassing the powder-filled and packaged package obtained in step (6);

[0015] (8) hot isostatic pressing the package obtained in step (7);

[0016] (9) Mechanically remove the sheath obtained in step (8), and process the redundant inner cavity boss to ensure the outline size, so as to obtain the target titanium alloy-based composite material powder component.

[0017] The atomization method in step (1) is electrode induction melting gas atomization method or plasma rotating electrode atomization method.

[0018] In the step (2), magnetic separation and electrostatic separation technology are used for screening and impurity removal.

[0019] In the step (3), the particle size of the Ti60 powder is ≤250 μm, and the particle size of the TiB2 powder is 3 to 20 μm.

[0020] The ball milling mixing process conditions in step (4) are as follows: the diameter of the steel ball is 1 to 20 mm, the ball-to-material ratio is 1 / 6 to 1 / 3, the ball milling time is 2 to 20 h, and the ball milling speed is 200-400 rpm.

[0021] The sleeve structure described in step (5) includes an outer sleeve, an inner sleeve, a sleeve bottom, a sleeve cover, a process block and a process groove, wherein the outer sleeve is an offset profile of the outer profile of the target component; the inner sleeve is an offset profile of the inner profile of the target component; the sleeve bottom and the sleeve cover are plugging covers for closing the cavity; the inner sleeve is located inside the outer sleeve, and the outer sleeve and the inner sleeve are respectively connected to the sleeve bottom and the sleeve cover to form a closed powder loading cavity; the process block is arranged between the outer sleeve and the inner sleeve for preparing the side holes of the target component, and the process holes are provided on the outer surface of the inner sleeve as positioning holes to ensure the accurate position of the side holes of the target product; the process groove is arranged on the outer surface of the inner sleeve for preparing the reinforcing ring ribs of the target component.

[0022] The degassing process conditions in step (7) are as follows: the degassing temperature is 500-700°C, the temperature is kept for 4-6 hours, and the vacuum degree is ≤5×10 -3 Pa.

[0023] The hot isostatic pressing process conditions in step (8) are as follows: the hot isostatic pressing temperature is 1100-1300° C., the pressure is not less than 130 MPa, and the holding time is 2-5 h.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] (1) The present invention adopts hot isostatic pressing technology to densify high-temperature titanium alloy powder and TiB2 powder under high temperature and high pressure, which can effectively avoid uneven organization and composition, obtain fine equiaxed grains, and improve its mechanical properties.

[0026] (2) The present invention can realize direct forming of the inner cavity structure of the target product through hot isostatic pressing process design, and realize that the room temperature and high temperature strength of the target product is equivalent to that of the forging, and the plasticity is significantly higher than that of the forging.

[0027] (3) The present invention can realize the integrated control and manufacturing of the organization, performance and structure of the target product, and can also be extended to other aerospace high-temperature titanium alloy-based thin-walled complex thin-walled components. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a microscopic photo of the morphology of Ti60 spherical powder in Example 1 of the present invention;

[0029] Figure 2 This is a schematic diagram of a hot isostatic pressing jacket of a thin-walled cylindrical structure according to Example 1 of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of the titanium alloy-based composite material according to Example 1 of the present invention;

[0031] Figure 4 The mechanical properties of the titanium alloy-based composite material of Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0033] The present invention provides a near-net-shape forming method for a titanium alloy-based composite material powder component, comprising the following steps:

[0034] (1) A Ti60 alloy ingot is obtained by 2-3 consumable arc melting, a Φ20-100 mm forged rod is obtained by forging deformation, and Ti60 powder is prepared by atomization method;

[0035] (2) screening and removing impurities from the titanium alloy powder obtained in step (1) to obtain clean Ti60 powder;

[0036] (3) preparing TiB2 powder and Ti60 powder in proportion to ensure that the mass fraction of TiB generated after hot isostatic pressing is 4 to 10%;

[0037] (4) ball milling the TiB2 and Ti60 powders prepared in step (3) and mixing them under argon protection;

[0038] (5) Manufacturing and welding the sheath structure according to the shape of the target structural part;

[0039] (6) Filling the TiB2 and Ti60 mixed powder obtained in step (4) into the sheath structure obtained in step (5), compacting the powder, and welding and encapsulating the degassing pipe and the sheath;

[0040] (7) degassing the powder-filled and packaged package obtained in step (6);

[0041] (8) hot isostatic pressing the package obtained in step (7);

[0042] (9) Mechanically remove the sheath obtained in step (8), and process the redundant inner cavity boss to ensure the outline size, so as to obtain the target titanium alloy-based composite material powder component.

[0043] The atomization method in step (1) is electrode induction melting gas atomization method or plasma rotating electrode atomization method.

[0044] In the step (2), magnetic separation and electrostatic separation technology are used for screening and impurity removal.

[0045] In the step (3), the particle size of the Ti60 powder is ≤250 μm, and the particle size of the TiB2 powder is 3 to 20 μm.

[0046] The ball milling mixing process conditions in step (4) are as follows: the diameter of the steel ball is 1 to 20 mm, the ball-to-material ratio is 1 / 6 to 1 / 3, the ball milling time is 2 to 20 h, and the ball milling speed is 200-400 rpm.

[0047] The sheath structure of step (5) comprises an outer sheath 1, an inner sheath 2, a sheath bottom 3, a sheath cover 4, a process block 6 and a process groove 8, wherein the outer sheath 1 is an offset profile of the outer profile of the target component; the inner sheath 2 is an offset profile of the inner profile of the target component; the sheath bottom 3 and the sheath cover 4 are plugging covers for closing the cavity; the outer sheath 1 and the inner sheath 2 are respectively connected to the sheath bottom 3 and the sheath cover 4 to form a closed powder loading cavity 5; the two ends of the process block 6 are respectively connected to the outer sheath 1 and the inner sheath 2 to prepare the side holes of the target component; the outer surface of the inner sheath 2 is provided with a process hole 7 as a positioning hole to ensure the accurate position of the side hole of the target product; the process groove 8 is arranged on the outer surface of the inner sheath 2 to prepare the reinforcing annular ribs of the target component.

[0048] The degassing process conditions in step (7) are as follows: the degassing temperature is 500-700°C, the temperature is kept for 4-6 hours, and the vacuum degree is ≤5×10 -3 Pa.

[0049] The hot isostatic pressing process conditions in step (8) are as follows: the hot isostatic pressing temperature is 1100-1300° C., the pressure is not less than 130 MPa, and the holding time is 2-5 h.

[0050] Example 1

[0051] The target product of this embodiment is a cylindrical structural part with a diameter of 330 mm, a height of 500 mm, and a wall thickness of 3 mm, and the inner surface has 4 annular ribs, 24 bosses and 4 side hole structures.

[0052] (1) Preparation of high-temperature titanium alloy powder: Ti60 nominal composition (Ti-5.7Al-4.0Sn-3.5Zr-0.4Mo-0.4Si-0.4Nb-1Ta-0.05C) is melted into a Φ220mm ingot by vacuum consumable arc melting. The ingot is melted three times to make the composition uniform, and its β transformation temperature is measured to be 1040℃. Subsequently, the billet is forged into a Φ140mm bar in the 1080℃ range, and then finally forged into a Φ60mm bar in the 990-1010℃ range and polished. Ti60 powder is prepared by plasma rotating electrode atomization method, and magnetic separation and electrostatic separation technology are used to screen the Ti60 alloy powder and remove impurities to obtain clean Ti60 alloy powder. The particle size of the clean high-temperature titanium alloy powder is 60-250μm; Figure 1 Shown is a microscopic photograph of the prepared Ti60 spherical powder morphology;

[0053] (2) Composition design: The composition ratio is determined according to the target performance required. The TiB2 powder and Ti60 powder are calculated by mass percentage, with a TiB mass percentage of 6% and a TiB2 powder particle size of 5 μm.

[0054] (3) Powder mixing: The Ti60 spherical powder and TiB2 powder prepared in (2) are mixed uniformly by low-energy planetary ball milling, so that the TiB2 powder is evenly coated on the surface of the Ti60 spherical powder; high-purity argon gas is introduced into the powder mixing process for protection, the steel ball diameter is 4 mm, the ball-to-material ratio is 4:1, the ball milling speed is 200 rpm, the ball milling is stopped for 10 minutes after 20 minutes, and the total ball milling time is 8 hours;

[0055] (4) Package design: Design the package structure according to the characteristics of the target product. Its structural form is as follows: Figure 2 As shown, it includes: an outer sleeve 1, an inner sleeve 2, a sleeve bottom 3, a sleeve cover 4, a powder loading cavity 5, a process block 6, and an exhaust pipe 9. The sleeve material is carbon steel or stainless steel. The main structure of the sleeve is an outer sleeve 1, an inner sleeve 2, a sleeve bottom 3, a sleeve cover 4, a process block 6, a process hole 7, and a process groove 8. The outer sleeve 1 is the offset profile of the outer profile of the target product; the inner sleeve 2 is the offset profile of the inner profile of the target product; the sleeve bottom 3 and the sleeve cover 4 are plugging covers for cavity sealing; 8 is a process groove at the inner profile, which is to solve the four reinforcing ring ribs inside the target, and its size should envelop the height and depth of the ring ribs; the process block 6 and the process hole 7 are to solve the side hole of the target product, and the process hole should be smaller than the outline of the target product hole. The process hole 7 is a positioning hole to ensure the accurate position of the side hole of the target product. The process block is assembled by interference fit; the inner sleeve, the outer sleeve, the sleeve cover 1 and the sleeve cover 2 are assembled by argon arc welding. The above tooling design can ensure the cavity accuracy, thus achieving near-net-shape of the target product;

[0056] (5) Package assembly and packaging: Clean the package, and perform groove welding on the inner package, outer package, package bottom, and process block in sequence according to the package structure designed in step (4);

[0057] (6) Powder filling: The powder mixed evenly in step (3) is filled into the package that has been assembled and welded. During the powder filling process, the powder is compacted by means of vibration, shaking, etc. Then, the package cover and the package are welded and sealed, and the exhaust pipe 9 is connected;

[0058] (7) Degassing: Place the package packaged after welding in step (6) in a muffle furnace and heat it to 650°C for 6 hours until the vacuum degree of the package is ≤5×10 -3 Pa; take out the sheath, forge the exhaust pipe and seal the sheath;

[0059] (8) Hot isostatic pressing: The package that has been degassed in step (7) is placed in a hot isostatic pressing furnace, heated to 1200°C, set to a pressure of 150 MPa, and kept at this temperature for 4 hours; after the heat preservation is completed, the package is cooled with the furnace, and the package is taken out of the furnace when the temperature drops below 300°C.

[0060] (9) Removal of the sheath: The sheath completed by hot isostatic pressing in (8) is removed by lathing, and the boss and rib parts are slightly processed until they are shiny, thus obtaining the target high-temperature titanium alloy-based thin-walled cylindrical parts. Figure 3 Shown is a schematic diagram of the organization of titanium alloy-based composite materials; Figure 4 Shown is the mechanical properties diagram of titanium alloy matrix composite materials.

[0061] The above description is only the best specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

[0062] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A near-net-shape forming method for titanium alloy-based composite material powder components, characterized in that: The steps include: (1) A Ti60 alloy ingot is obtained by 2-3 consumable arc melting, a Φ20-100 mm forged rod is obtained by forging deformation, and Ti60 powder is prepared by atomization method; (2) screening and removing impurities from the titanium alloy powder obtained in step (1) to obtain clean Ti60 powder; (3) preparing TiB2 powder and Ti60 powder in proportion to ensure that the mass fraction of TiB generated after hot isostatic pressing is 4 to 10%; (4) ball milling the TiB2 and Ti60 powders prepared in step (3) and mixing them under argon protection; (5) Manufacturing and welding the sheath structure according to the shape of the target structural part; (6) Filling the TiB2 and Ti60 mixed powder obtained in step (4) into the sheath structure obtained in step (5), compacting the powder, and welding and encapsulating the degassing pipe and the sheath; (7) degassing the powder-filled and packaged package obtained in step (6); (8) hot isostatic pressing the package obtained in step (7); (9) Mechanically remove the sheath obtained in step (8), and process the redundant inner cavity boss to ensure the outline size, so as to obtain the target titanium alloy-based composite material powder component.

2. A near-net-shape forming method for a titanium alloy-based composite material powder component according to claim 1, characterized in that: The atomization method in step (1) is electrode induction melting gas atomization method or plasma rotating electrode atomization method.

3. The near-net-shape forming method of a titanium alloy-based composite material powder component according to claim 1, characterized in that: In the step (2), magnetic separation and electrostatic separation technology are used for screening and impurity removal.

4. The near-net-shape forming method of a titanium alloy-based composite material powder component according to claim 1, characterized in that: In the step (3), the particle size of the Ti60 powder is ≤250 μm, and the particle size of the TiB2 powder is 3 to 20 μm.

5. The near-net-shape forming method of a titanium alloy-based composite material powder component according to claim 1, characterized in that: The ball milling mixing process conditions in step (4) are as follows: the diameter of the steel ball is 1 to 20 mm, the ball-to-material ratio is 1 / 6 to 1 / 3, the ball milling time is 2 to 20 h, and the ball milling speed is 200-400 rpm.

6. The near-net-shape forming method of a titanium alloy-based composite material powder component according to claim 1, characterized in that: The encapsulation structure in step (5) comprises an outer encapsulation (1), an inner encapsulation (2), an encapsulation bottom (3), an encapsulation cover (4), a process block (6) and a process groove (8); the outer encapsulation (1) is an offset profile of the outer profile of the target component; the inner encapsulation (2) is an offset profile of the inner profile of the target component; the encapsulation bottom (3) and the encapsulation cover (4) are plugging covers for sealing the mold cavity; the inner encapsulation (2) is located inside the outer encapsulation (1); the outer encapsulation (1) and the inner encapsulation (2) are respectively connected to the encapsulation bottom (3) and the encapsulation cover (4) to form a closed powder loading cavity (5); the process block (6) is arranged between the outer encapsulation (1) and the inner encapsulation (2) for preparing the side hole of the target component; the outer surface of the inner encapsulation (2) is provided with a process hole (7) as a positioning hole to ensure the accurate position of the side hole of the target product; the process groove (8) is arranged on the outer surface of the inner encapsulation (2) for preparing the reinforcing annular rib of the target component.

7. The near-net-shape forming method of a titanium alloy-based composite material powder component according to claim 1, characterized in that: The degassing process conditions in step (7) are as follows: the degassing temperature is 500-700°C, the temperature is kept for 4-6 hours, and the vacuum degree is ≤5×10 - 3 Pa.

8. The near-net-shape forming method of a titanium alloy-based composite material powder component according to claim 1, characterized in that: The hot isostatic pressing process conditions in step (8) are as follows: the hot isostatic pressing temperature is 1100-1300° C., the pressure is not less than 130 MPa, and the holding time is 2-5 h.

9. A titanium alloy-based composite material powder component, characterized in that: Prepared according to the forming method according to any one of claims 1-8.

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