Electron beam additive manufacturing method and system for titanium-aluminum intermetallic compound

Abstract

The invention relates to an electron beam additive manufacturing method and system for a titanium-aluminum intermetallic compound, and the electron beam additive manufacturing method for the titanium-aluminum intermetallic compound is realized through the electron beam additive manufacturing system for the titanium-aluminum intermetallic compound. The invention relates to a method for carrying out layer-by-layer stacking forming according to a preset track, carrying out follow-up scanning heating by adopting at least two electron beams and homogenizing a temperature field of a formed part, in particular to a rapid additive manufacturing method for a high-temperature material which is difficult to weld and needs a small temperature gradient and low stress in the forming process. The method can solve the problems of high manufacturing difficulty, high manufacturing cost and the like of the current common processing technology of intermetallic compound parts such as titanium and aluminum.

Description

Technical Field

[0001] The present application relates to the technical field of electron beam additive manufacturing, and in particular to an electron beam additive manufacturing method and system for titanium-aluminum intermetallic compounds. Background Art

[0002] Intermetallic compounds such as titanium and aluminum are increasingly widely used in the fields of aerospace and energy and power due to their high temperature resistance, low density and high strength. At present, the processing of intermetallic compounds such as titanium and aluminum usually adopts forming methods such as casting, precision forging, powder metallurgy and hot extrusion. Intermetallic compounds have low ductility, low fracture toughness and poor room temperature plasticity. Commonly used processing methods are difficult to control the defects and impurity element components generated during the processing process, and the subsequent processing is difficult, making it difficult to significantly improve the manufacturing quality of complex structures of intermetallic compounds, and the manufacturing cost remains high. Electron beam selective melting additive manufacturing technology provides a new method for the processing and manufacturing of intermetallic compounds such as titanium and aluminum. Through high-frequency scanning preheating of electron beams (≥1100℃), the powder bed of the additive manufacturing process is kept in a high temperature state with a uniform temperature field, and the forming temperature is kept above the ductile-brittle transition point, which can effectively solve the problems of cracking and deformation caused by large temperature gradients in the forming process of intermetallic compounds such as titanium and aluminum. The Italian Aerospace Industry Group, Swedish Arcam Company and other units have cooperated to prepare a variety of γ-TiAl alloy blades using electron beam powder bed technology, enriching the connotation of processing and manufacturing technology of intermetallic compounds such as titanium and aluminum. In 2006, GE Additive's titanium-aluminum alloy low-pressure turbine blades made using electron beam powder bed additive manufacturing were used in the GEnX engines selected for Boeing 787 and 747-8. Titanium-aluminum blades have also been used in the LEAP engine launched by Snecma. Pratt and Whitney and Rolls-Royce have also announced that they will use titanium-aluminum intermetallic compounds in new aircraft engines. The development and application of titanium-aluminum and other intermetallic compounds have received widespread attention from governments and research institutions at home and abroad.

[0003] However, the technical difficulty of the equipment and process is relatively high. There are problems such as the difficulty in controlling the consistency of performance of different parts of the formed parts, the evaporation of Al elements easily causing interlayer segregation, and the low utilization rate of powder in the forming process, the extremely high cost of the required powder, and the high manufacturing cost. In addition, the powder blowing phenomenon caused by the discharge of the electron gun due to vacuum mutations, high-voltage pulse interference, etc. during the forming process can easily force the processing process to stop, affecting the forming quality. Summary of the invention

[0004] The present application provides an electron beam additive manufacturing method and system for titanium-aluminum intermetallic compounds, which solves the problem of high manufacturing difficulty and high manufacturing cost of commonly used processing technologies for titanium-aluminum and other intermetallic compound parts.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] In a first aspect, the present application provides an electron beam additive manufacturing method for titanium aluminum intermetallic compounds, which is implemented by an electron beam additive manufacturing system for titanium aluminum intermetallic compounds;

[0007] The electron beam additive manufacturing system for titanium-aluminum intermetallic compounds comprises a coaxial powder feeding electron gun, an ultrasonic powder feeding barrel, a first infrared thermal imager, a second infrared thermal imager, a first high-frequency scanning electron gun, and a second high-frequency scanning electron gun;

[0008] The electron beam additive manufacturing method of the titanium-aluminum intermetallic compound comprises:

[0009] Install a first infrared thermal imager and a first high-frequency scanning electron gun on one side of the formed part, and install a second infrared thermal imager and a second high-frequency scanning electron gun on the other side of the formed part;

[0010] Turning on the first high-frequency scanning electron gun and the second high-frequency scanning electron gun to output beams to the forming area respectively, and detecting the temperature of the forming area by using the first infrared thermal imager and the second infrared thermal imager;

[0011] When the temperature of the forming area reaches the preset temperature range, the coaxial powder feeding electron gun and the ultrasonic powder feeding barrel are positioned to the starting point of the current forming layer to carry out melting and forming of titanium aluminum powder;

[0012] After the current forming layer is formed, the temperature of the forming area is detected by the first infrared thermal imager and the second infrared thermal imager to maintain the temperature within a preset temperature range and to ensure that the temperature field is evenly distributed;

[0013] The coaxial powder feeding electron gun and the ultrasonic powder feeding barrel are controlled to melt and form the titanium aluminum powder of the next forming layer, and the previous step is repeated until all the forming layers of the formed part are formed.

[0014] Further, the first high-frequency scanning electron gun and the second high-frequency scanning electron gun each include a scanning coil current control unit, a power supply, and a focusing unit, and the electron beam additive manufacturing system for titanium-aluminum intermetallic compounds also includes an online temperature control system;

[0015] The step of starting the first high-frequency scanning electron gun and the second high-frequency scanning electron gun to output beams to the forming area respectively includes:

[0016] The online temperature control system starts the scanning coil current control unit of the first high-frequency scanning electron gun and the second high-frequency scanning electron gun;

[0017] The online temperature control system turns on the power of the first high-frequency scanning electron gun and the second high-frequency scanning electron gun, so that the first high-frequency scanning electron gun and the second high-frequency scanning electron gun output beams respectively;

[0018] The online temperature control system turns on the focusing units of the first high-frequency scanning electron gun and the second high-frequency scanning electron gun, so that the beam spots of the beams output by the first high-frequency scanning electron gun and the second high-frequency scanning electron gun are defocused.

[0019] Furthermore, after the first high-frequency scanning electron gun and the second high-frequency scanning electron gun are turned on to output beams to the forming area respectively, the method further includes:

[0020] The beam of the first high-frequency scanning electron gun forms a first electron beam scanning area on the metal substrate, and the beam of the second high-frequency scanning electron gun forms a second electron beam scanning area on the metal substrate.

[0021] Furthermore, the electron beam additive manufacturing system for titanium-aluminum intermetallic compounds also includes a forming trajectory control PLC system and an XY motion mechanism;

[0022] The method of positioning the coaxial powder feeding electron gun and the ultrasonic powder feeding barrel to the starting point of the current forming layer to perform melting forming of titanium aluminum powder includes:

[0023] The forming trajectory control PLC system positions the coaxial powder feeding electron gun to the starting point of the current forming layer by controlling the XY motion mechanism;

[0024] The coaxial powder feeding electron gun outputs a circular electron beam to melt the titanium aluminum powder fed synchronously by the ultrasonic powder feeding barrel;

[0025] After the titanium aluminum powder at the starting point is melted and formed, the forming trajectory control PLC system controls the XY motion mechanism to position the coaxial powder feeding electron gun to the next deposition point of the current forming layer;

[0026] Until all the deposition points of the current forming layer are deposited and formed, the forming trajectory control PLC system stops the coaxial powder feeding electron gun from outputting the annular electron beam and the ultrasonic powder feeding barrel stops feeding the titanium aluminum powder.

[0027] Furthermore, after positioning the coaxial powder feeding electron gun and the ultrasonic powder feeding barrel to the starting point of the current forming layer and melting and forming the titanium aluminum powder, the method further includes:

[0028] The forming trajectory control PLC system transmits the forming completion signal of the current forming layer to the online temperature control system, and the online temperature control system calculates the height of the current forming part according to the slice thickness of the forming part;

[0029] The first high-frequency scanning electron gun adjusts the scanning width of the first electron beam scanning area according to the height of the current formed part, and the second high-frequency scanning electron gun adjusts the scanning width of the second electron beam scanning area according to the height of the current formed part.

[0030] Furthermore, the method of detecting the temperature of the forming area by the first infrared thermal imager and the second infrared thermal imager so that the temperature is maintained within a preset temperature range and the temperature field is evenly distributed includes:

[0031] The first infrared thermal imager and the second infrared thermal imager transmit the collected panoramic thermal images to the online temperature control system, and the online temperature control system analyzes the panoramic thermal images to obtain the temperature field distribution state on both sides of the formed part;

[0032] The temperature fields on the two surfaces of the formed part are divided into multiple sub-areas. By controlling the residence time of the beams generated by different electron guns in different sub-areas on the corresponding surfaces of the formed part, the temperatures on both sides of the formed part are maintained within the preset temperature range and the temperature field is evenly distributed.

[0033] Furthermore, the electron beam additive manufacturing system for titanium-aluminum intermetallic compounds further includes a Z-axis workbench;

[0034] The method of controlling the coaxial powder feeding electron gun and the ultrasonic powder feeding barrel to melt and form the titanium aluminum powder of the next forming layer includes:

[0035] The forming trajectory control PLC system controls the Z-axis worktable to move downward to slice thickness, retrieves the filling path information of the next forming layer, and transmits it to the current forming layer;

[0036] Repeat the steps of melting and forming the titanium-aluminum powder for the current forming layer to complete the melting and forming of the titanium-aluminum powder for the next forming layer.

[0037] Furthermore, after all the shaping layers of the shaped part are formed, the method further comprises:

[0038] The online temperature control system enables the first high-frequency scanning electron gun and the second high-frequency scanning electron gun to output at the maximum beam power respectively, and perform high-frequency scanning in a defocused state. The scanning range covers the entire area of ​​the formed part, and the temperature of the entire formed part is maintained within a preset temperature range for a certain period of time;

[0039] gradually reducing the beam power output of the first high-frequency scanning electron gun and the second high-frequency scanning electron gun at a preset rate until it reaches zero;

[0040] The online temperature control system turns off the power supply, the focusing unit, and the scanning coil current control unit of the first high-frequency scanning electron gun and the second high-frequency scanning electron gun;

[0041] After the molded part and the metal substrate are naturally cooled to room temperature in a vacuum state, the molded part and the metal substrate are taken out.

[0042] In a second aspect, the present application provides an electron beam additive manufacturing system for titanium aluminum intermetallic compounds, which is used to implement the electron beam additive manufacturing method for titanium aluminum intermetallic compounds as described above;

[0043] The electron beam additive manufacturing system for titanium-aluminum intermetallic compounds comprises a coaxial powder feeding electron gun, an ultrasonic powder feeding barrel, a first infrared thermal imager, a second infrared thermal imager, a first high-frequency scanning electron gun, and a second high-frequency scanning electron gun.

[0044] Furthermore, the first high-frequency scanning electron gun and the second high-frequency scanning electron gun each include a scanning coil current control unit, a power supply, and a focusing unit;

[0045] The electron beam additive manufacturing system for titanium-aluminum intermetallic compounds also includes an online temperature control system, a forming trajectory control PLC system, an XY motion mechanism, and a Z workbench.

[0046] The first aspect of the present application provides an electron beam additive manufacturing method for titanium-aluminum intermetallic compounds, which adopts electron beam coaxial powder feeding melting and precise near-net forming. At least two electron beams are arranged on both sides of the formed part to perform high-frequency scanning to keep the overall temperature of the formed part within a preset temperature range. The temperature field distribution is uniformed through the collection and analysis of infrared panoramic thermal images, which reduces stress deformation and cracking, significantly improves the electron beam additive manufacturing yield and processing quality of titanium-aluminum and other intermetallic compounds, greatly improves the powder utilization rate, reduces the powder cost, and solves the problems of the difficulty and high manufacturing cost of the current commonly used processing technology for titanium-aluminum and other intermetallic compound parts.

[0047] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 A schematic diagram of the framework of the electron beam additive manufacturing system for titanium aluminum intermetallic compounds provided in this application;

[0050] Figure 2 This is an application scenario diagram of the electron beam additive manufacturing method for titanium aluminum intermetallic compounds provided in this application;

[0051] Figure 3 A schematic flow chart of the electron beam additive manufacturing method for titanium-aluminum intermetallic compounds provided in this application.

[0052] Figure numerals: 1. coaxial powder feeding electron gun; 101. annular electron beam; 102. titanium aluminum powder; 2. ultrasonic powder feeding barrel; 3. first high-frequency scanning electron gun; 4. second high-frequency scanning electron gun; 5. formed part; 6. metal substrate; 7. Z-axis workbench; 8. first infrared thermal imager; 9. second infrared thermal imager; 10. XY-axis motion mechanism; 11. online temperature control system; 12. forming trajectory control PLC system; 13. focusing unit of the first high-frequency scanning electron gun; 14. focusing unit of the second high-frequency scanning electron gun; 15. scanning coil current control unit of the first high-frequency scanning electron gun; 16. scanning coil current control unit of the second high-frequency scanning electron gun; 17. power supply of the first high-frequency scanning electron gun; 18. power supply of the second high-frequency scanning electron gun. DETAILED DESCRIPTION

[0053] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0054] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0055] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0056] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. "Multiple" means "two or more".

[0057] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but are not intended to limit the scope of the present application.

[0058] This embodiment provides an electron beam additive manufacturing method for titanium aluminum intermetallic compounds, which is implemented by an electron beam additive manufacturing system for titanium aluminum intermetallic compounds. Figure 1 , Figure 2 As shown, the electron beam additive manufacturing system of the titanium-aluminum intermetallic compound includes: a coaxial powder feeding electron gun 1, an ultrasonic powder feeding barrel 2, a first infrared thermal imager 8, a second infrared thermal imager 9, a first high-frequency scanning electron gun 3, a second high-frequency scanning electron gun 4 installed on both sides of the formed part 5, and a focusing unit 13 of the first high-frequency scanning electron gun, a focusing unit 14 of the second high-frequency scanning electron gun, a scanning coil current control unit 15 of the first high-frequency scanning electron gun, a scanning coil current control unit 16 of the second high-frequency scanning electron gun, a power supply 17 of the first high-frequency scanning electron gun, a power supply 18 of the second high-frequency scanning electron gun, an online temperature control system 11, a forming trajectory control PLC system 12, an XY motion mechanism 10, a Z-axis workbench 7, etc.

[0059] The electron beam additive manufacturing method of the titanium-aluminum intermetallic compound comprises:

[0060] The first infrared thermal imager 8 and the first high-frequency scanning electron gun 3 are installed on one side of the formed part 5, and the second infrared thermal imager 9 and the second high-frequency scanning electron gun 4 are installed on the other side of the formed part 5;

[0061] Turn on the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 to output beams to the forming area respectively, and detect the temperature of the forming area by the first infrared thermal imager 8 and the second infrared thermal imager 9;

[0062] When the temperature of the forming area reaches the preset temperature range, the coaxial powder feeding electron gun 1 and the ultrasonic powder feeding barrel 2 are positioned to the starting point of the current forming layer to melt and form the titanium aluminum powder 102; after the current forming layer is formed, the temperature of the forming area is detected by the first infrared thermal imager 8 and the second infrared thermal imager 9 to maintain the temperature within the preset temperature range and to ensure that the temperature field is evenly distributed;

[0063] The coaxial powder feeding electron gun 1 and the ultrasonic powder feeding barrel 2 are controlled to melt and form the titanium aluminum powder 102 of the next forming layer, and the previous step is repeated until all the forming layers of the formed part 5 are formed.

[0064] Specifically, starting the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 to output beams to the forming area respectively includes:

[0065] The online temperature control system 11 turns on the scanning coil current control units 15 and 16 of the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4;

[0066] The online temperature control system 11 turns on the power supplies 17 and 18 of the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4, so that the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 output beams respectively;

[0067] The online temperature control system 11 turns on the focusing units 13 and 14 of the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 to defocus the beam spots of the beams output by the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 , respectively.

[0068] Specifically, after the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 are turned on to output beams to the forming area respectively, the method further includes:

[0069] The beam of the first high-frequency scanning electron gun 3 forms a first electron beam scanning area on the metal substrate 6 , and the beam of the second high-frequency scanning electron gun 4 forms a second electron beam scanning area on the metal substrate 6 .

[0070] Specifically, the coaxial powder feeding electron gun 1 and the ultrasonic powder feeding barrel 2 are positioned at the starting point of the current forming layer to melt and form the titanium aluminum powder 102, including:

[0071] The forming trajectory control PLC system 12 positions the coaxial powder feeding electron gun 1 to the starting point of the current forming layer by controlling the XY motion mechanism 10;

[0072] The coaxial powder feeding electron gun 1 outputs a circular electron beam 101 to melt the titanium aluminum powder 102 synchronously fed by the ultrasonic powder feeding barrel 2;

[0073] After the titanium aluminum powder 102 at the starting point is melted and formed, the forming trajectory control PLC system 12 controls the XY motion mechanism 10 to position the coaxial powder feeding electron gun 1 to the next deposition point of the current forming layer;

[0074] Until all the deposition points of the current forming layer are deposited and formed, the forming trajectory control PLC system 12 stops the coaxial powder feeding electron gun 1 from outputting the annular electron beam 101 and the ultrasonic powder feeding barrel 2 stops feeding the titanium aluminum powder 102.

[0075] Specifically, after positioning the coaxial powder feeding electron gun 1 and the ultrasonic powder feeding barrel 2 at the starting point of the current forming layer and melting and forming the titanium aluminum powder 102, the method further includes:

[0076] The forming trajectory control PLC system 12 transmits the forming completion signal of the current forming layer to the online temperature control system 11, and the online temperature control system 11 calculates the height of the current forming part 5 according to the slice thickness of the forming part 5;

[0077] The first high-frequency scanning electron gun 3 adjusts the scanning width of the first electron beam scanning area according to the height of the current formed part 5 , and the second high-frequency scanning electron gun 4 adjusts the scanning width of the second electron beam scanning area according to the height of the current formed part 5 .

[0078] Specifically, the temperature of the forming area is detected by the first infrared thermal imager 8 and the second infrared thermal imager 9, so that the temperature is maintained within a preset temperature range and the temperature field is evenly distributed, including:

[0079] The first infrared thermal imager 8 and the second infrared thermal imager 9 transmit the collected panoramic thermal image to the online temperature control system 11, and the online temperature control system 11 analyzes the panoramic thermal image to obtain the temperature field distribution state on both sides of the formed part 5;

[0080] The temperature fields on the two surfaces of the formed part 5 are divided into multiple sub-areas. By controlling the residence time of the beams generated by different electron guns in different sub-areas on the corresponding surfaces of the formed part, the temperatures on both sides of the formed part 5 are maintained within a preset temperature range and the temperature field is evenly distributed.

[0081] Specifically, controlling the coaxial powder feeding electron gun 1 and the ultrasonic powder feeding barrel 2 to melt and form the titanium aluminum powder 102 of the next forming layer includes:

[0082] The forming trajectory control PLC system 12 controls the Z-axis worktable 7 to move downward by the slice thickness, retrieves the filling path information of the next forming layer, and transmits it to the current forming layer;

[0083] The steps of melting and forming the titanium aluminum powder 102 of the current forming layer are repeated to complete the melting and forming of the titanium aluminum powder 102 of the next forming layer.

[0084] Specifically, after all the shaping layers of the shaped part 5 are formed, the process further includes:

[0085] The online temperature control system 11 enables the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 to output at the maximum beam power respectively, and to perform high-frequency scanning in a defocused state, so that the scanning range covers the entire area of ​​the formed part 5, and the temperature of the entire formed part 5 is maintained within a preset temperature range for a certain period of time;

[0086] Gradually reducing the beam power output of the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 at a preset rate until it reaches zero;

[0087] The online temperature control system 11 turns off the power supplies 17 and 18 of the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4, the focusing units 13 and 14, and the scanning coil current control units 15 and 16;

[0088] After the molded product 5 and the metal substrate 6 are naturally cooled to room temperature in a vacuum state, the molded product 5 and the metal substrate 6 are taken out.

[0089] In applications, such as Figure 2 As shown, the coaxial powder feeding electron gun 1 moves in the XY direction, and the formed part 5 moves in the Z direction. During the forming process, the coaxial powder feeding electron gun 1 melts and forms by feeding powder, and the XY direction motion mechanism 10 drives the coaxial powder feeding electron gun 1 to move and form a layer. After forming a layer, the Z direction workbench 7 drives the formed part 5 to move down a layer, and this is repeated until the formed part 5 is formed.

[0090] A cold cathode coaxial powder feeding electron gun 1 is used, which has a large power and can melt intermetallic compound powders such as titanium and aluminum, and has a dense internal structure; a low vacuum environment can avoid oxidation and reduce interlayer segregation caused by evaporation of the Al element; directional energy deposition has a high deposition rate while improving component accuracy and powder utilization efficiency; two infrared thermal imagers 8 and 9 collect thermal images of the formed parts and feed them back to the online temperature control system, which can fully analyze the temperature field distribution state of the formed part 5 and formulate a strategy for homogenizing the temperature field. A method of partitioning and time-sharing high-frequency scanning of two auxiliary electron guns 3 and 4 to homogenize the temperature field of the formed part 5 is used to reduce deformation of the formed part 5 and reduce cracking of the formed part 5.

[0091] When the vacuum degree of the vacuum chamber reaches the set requirements and the water, electricity and gas are in good condition, Figure 3 As shown, the electron beam additive manufacturing method for titanium aluminum intermetallic compound provided in this embodiment works as follows:

[0092] Step 1: The online temperature control system 11 turns on the scanning coil current control unit 15 of the first high-frequency scanning electron gun and the scanning coil current control unit 16 of the second high-frequency scanning electron gun, and the scanning frequency is not less than 20 kHz;

[0093] Step 2: The online temperature control system 11 turns on the power supply 17 of the first high-frequency scanning electron gun and the power supply 18 of the second high-frequency scanning electron gun, so that the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 output beams, and the beam power adjustment range is 100W to 3kW;

[0094] Step 3: The online temperature control system 11 turns on the focusing unit 13 of the first high-frequency scanning electron gun and the focusing unit 14 of the second high-frequency scanning electron gun, so that the beam spots of the output beams of the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 are defocused, and the beam spot diameter is 3-5 mm;

[0095] Step 4: The beam of the first high-frequency scanning electron gun 3 forms a first electron beam scanning area on the metal substrate 6, and the beam of the second high-frequency scanning electron gun 4 forms a second electron beam scanning area on the metal substrate 6. The first electron beam scanning area overlaps the second electron beam scanning area, and the width is d0 and the length is L0. The length L0 is ≥ the length L of the deposited part. s , the metal substrate 6 is made of titanium alloy; the titanium aluminum powder 102 is Ti-(42-49)Al-(0.1-10)X, the element X is any one or more of Cr, Nb, V, Mn, Ta, Mo, Zr, W, Si, C, Y and B, the powder is prepared by gas atomization method, and its particle size range is 45-150 μm;

[0096] Step 5: The first infrared thermal imager 8 and the second infrared thermal imager 9 detect whether the temperature of the deposition forming area of ​​the metal substrate 6 reaches 800-900° C. If not, jump to step 4; if the temperature of the deposition forming area of ​​the metal substrate 6 reaches 800-900° C., execute step 6;

[0097] Step 6: The forming trajectory control PLC system 12 positions the coaxial powder feeding electron gun 1 to the starting point of the current forming layer by controlling the XY motion mechanism 10; the coaxial powder feeding electron gun 1 outputs a circular electron beam 101 to melt the titanium aluminum powder 102 synchronously fed by the ultrasonic powder feeding barrel 2;

[0098] Step 7: After the titanium aluminum powder 102 at the starting point is melted and formed, the forming trajectory control PLC system 12 controls the XY motion mechanism 10 to position the coaxial powder feeding electron gun 1 to the next deposition point of the current forming layer. The coaxial powder feeding electron gun 1 keeps outputting the annular electron beam 101 unchanged, and melts the titanium aluminum powder 102 synchronously fed by the ultrasonic powder feeding barrel 2;

[0099] Step 8: The forming trajectory control PLC system 12 detects whether all deposition points of the current forming layer have been deposited and formed. If not, the coaxial powder feeding electron gun 1 is moved to the next deposition point of the current forming layer by controlling the XY motion mechanism 10. The coaxial powder feeding electron gun 1 keeps outputting the annular electron beam 101 unchanged, and melts the titanium aluminum powder 102 synchronously fed by the ultrasonic powder feeding barrel 2.

[0100] Step 9, repeating step 8 until all deposition points of the current forming layer are deposited and formed; the forming trajectory control PLC system 12 stops the coaxial powder feeding electron gun 1 from outputting the annular electron beam 101, and the ultrasonic powder feeding barrel 2 stops feeding the titanium aluminum powder 102;

[0101] Step 10, the forming trajectory control PLC system 12 transmits the deposition forming completion signal of the nth forming layer to the online temperature control system 11. The online temperature control system 11 calculates the height of the current forming part 5 as n×a according to the slice thickness a of the forming part 5, so that the scanning width of the first electron beam scanning area formed by the beam of the first high-frequency scanning electron gun 3 increases by (n-1)×a, becoming (n-1)×a+d0, and the scanning width of the second electron beam scanning area formed by the beam of the second high-frequency scanning electron gun 4 increases by (n-1)×a, becoming (n-1)×a+d0; the length L0 of the first electron beam scanning area formed by the beam of the first high-frequency scanning electron gun 3 remains unchanged, and the length L0 of the second electron beam scanning area formed by the beam of the second high-frequency scanning electron gun 4 remains unchanged;

[0102] Step 11, the first infrared thermal imager 8 and the second infrared thermal imager 9 transmit the collected panoramic thermal image to the online temperature control system 11, the online temperature control system 11 analyzes the panoramic thermal image to obtain the temperature field distribution state of the two surfaces of the formed part 5, and divides the temperature fields of the two surfaces of the formed part 5 into multiple sub-areas. Based on the principle of "the temperature difference between adjacent sub-areas is less than 20°C, and the temperature of the entire area is maintained at 800-900°C", by controlling the residence time of the beam generated by different electron guns in different sub-areas of the corresponding surface of the formed part 5, the temperature of the two surfaces of the formed part 5 is maintained at 800-900°C, and the temperature field is evenly distributed;

[0103] Step 12: Check whether all the forming layers of the formed part 5 have been deposited and formed. If so, jump to step 16; otherwise, go to step 13;

[0104] Step 13: The forming trajectory control PLC system 12 controls the Z-axis worktable 7 to move downward by a slice thickness a;

[0105] Step 14: The forming trajectory control PLC system 12 retrieves the filling path information of the n+1th forming layer and transmits it to the current forming layer nth layer;

[0106] Step 15, repeating steps 6 to 15 until all the forming layers of the formed part 5 are deposited and formed;

[0107] Step 16, the online temperature control system 11 makes the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 output with a beam power of 3kW respectively, and performs high-frequency scanning in a defocused state. The scanning range covers the entire area of ​​the formed part, and the temperature of the entire formed part 5 is maintained at 800-900°C for 30-40 minutes; according to the mode of reducing the beam power of the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 by 100W every 10 minutes, the beam power output of the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 is gradually reduced until the beam output of the first high-frequency scanning electron gun 3 and the second high-frequency scanning electron gun 4 is zero;

[0108] Step 17: The online temperature control system 11 turns off the power supply 17 of the first high-frequency scanning electron gun and the power supply 18 of the second high-frequency scanning electron gun; turns off the focusing unit 13 of the first high-frequency scanning electron gun and the focusing unit 14 of the second high-frequency scanning electron gun; turns off the scanning coil current control unit 15 of the first high-frequency scanning electron gun and the scanning coil current control unit 16 of the second high-frequency scanning electron gun;

[0109] After the molded product 5 and the metal substrate 6 are naturally cooled to room temperature in a vacuum state, the molded product 5 and the metal substrate 6 are taken out.

[0110] This embodiment also provides an electron beam additive manufacturing system for titanium aluminum intermetallic compounds, which is used to implement the electron beam additive manufacturing method for titanium aluminum intermetallic compounds as described above. Figure 1 and Figure 2 As shown, the electron beam additive manufacturing system of the titanium-aluminum intermetallic compound includes: a coaxial powder feeding electron gun 1, an ultrasonic powder feeding barrel 2, a first infrared thermal imager 8, a second infrared thermal imager 9, a first high-frequency scanning electron gun 3, a second high-frequency scanning electron gun 4 installed on both sides of the formed part 5, and a focusing unit 13 of the first high-frequency scanning electron gun, a focusing unit 14 of the second high-frequency scanning electron gun, a scanning coil current control unit 15 of the first high-frequency scanning electron gun, a scanning coil current control unit 16 of the second high-frequency scanning electron gun, a power supply 17 of the first high-frequency scanning electron gun, a power supply 18 of the second high-frequency scanning electron gun, an online temperature control system 11, a forming trajectory control PLC system 12, an XY motion mechanism 10, a Z-axis workbench 7, etc.

[0111] The electron beam additive manufacturing method and system for titanium-aluminum intermetallic compounds provided in the embodiment of the present application address the problems of difficulty in manufacturing and high manufacturing cost of the commonly used processing technologies for titanium-aluminum and other intermetallic compound parts. Cold cathode electron beam coaxial powder feeding melting and precision near-net forming are adopted. At least two electron beams are arranged on both sides of the formed part to maintain the overall temperature of the formed part at a high temperature of more than 900°C through high-frequency scanning. The temperature field distribution is uniformed by zone scanning heating through the collection and analysis of infrared panoramic thermal images, which reduces stress deformation and cracking, significantly improves the yield and processing quality of electron beam additive manufacturing of titanium-aluminum and other intermetallic compounds, greatly improves the powder utilization rate, and reduces the powder cost.

[0112] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned functions can be assigned to different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application.

[0113] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. An electron beam additive manufacturing method for titanium aluminum intermetallic compounds, characterized in that: This was achieved through an electron beam additive manufacturing system of titanium-aluminum intermetallic compounds; The electron beam additive manufacturing system for titanium-aluminum intermetallic compounds comprises a coaxial powder feeding electron gun, an ultrasonic powder feeding barrel, a first infrared thermal imager, a second infrared thermal imager, a first high-frequency scanning electron gun, and a second high-frequency scanning electron gun; The electron beam additive manufacturing method of the titanium-aluminum intermetallic compound comprises: Install a first infrared thermal imager and a first high-frequency scanning electron gun on one side of the formed part, and install a second infrared thermal imager and a second high-frequency scanning electron gun on the other side of the formed part; Turning on the first high-frequency scanning electron gun and the second high-frequency scanning electron gun to output beams to the forming area respectively, and detecting the temperature of the forming area by using the first infrared thermal imager and the second infrared thermal imager; When the temperature of the forming area reaches the preset temperature range, the coaxial powder feeding electron gun and the ultrasonic powder feeding barrel are positioned to the starting point of the current forming layer to carry out melting and forming of titanium aluminum powder; After the current forming layer is formed, the temperature of the forming area is detected by the first infrared thermal imager and the second infrared thermal imager to maintain the temperature within a preset temperature range and to ensure that the temperature field is evenly distributed; The coaxial powder feeding electron gun and the ultrasonic powder feeding barrel are controlled to melt and form the titanium aluminum powder of the next forming layer, and the previous step is repeated until all the forming layers of the formed part are formed.

2. The electron beam additive manufacturing method of titanium aluminum intermetallic compound according to claim 1, characterized in that: The first high-frequency scanning electron gun and the second high-frequency scanning electron gun both include a scanning coil current control unit, a power supply, and a focusing unit, and the electron beam additive manufacturing system for titanium-aluminum intermetallic compounds also includes an online temperature control system; The step of starting the first high-frequency scanning electron gun and the second high-frequency scanning electron gun to output beams to the forming area respectively includes: The online temperature control system starts the scanning coil current control unit of the first high-frequency scanning electron gun and the second high-frequency scanning electron gun; The online temperature control system turns on the power of the first high-frequency scanning electron gun and the second high-frequency scanning electron gun, so that the first high-frequency scanning electron gun and the second high-frequency scanning electron gun output beams respectively; The online temperature control system turns on the focusing units of the first high-frequency scanning electron gun and the second high-frequency scanning electron gun, so that the beam spots of the beams output by the first high-frequency scanning electron gun and the second high-frequency scanning electron gun are defocused.

3. The electron beam additive manufacturing method of titanium aluminum intermetallic compound according to claim 1, characterized in that: After the first high-frequency scanning electron gun and the second high-frequency scanning electron gun are turned on to output beams to the forming area respectively, the method further includes: The beam of the first high-frequency scanning electron gun forms a first electron beam scanning area on the metal substrate, and the beam of the second high-frequency scanning electron gun forms a second electron beam scanning area on the metal substrate.

4. The electron beam additive manufacturing method of titanium aluminum intermetallic compound according to claim 1, characterized in that: The electron beam additive manufacturing system for titanium-aluminum intermetallic compounds also includes a forming trajectory control PLC system and an XY motion mechanism; The method of positioning the coaxial powder feeding electron gun and the ultrasonic powder feeding barrel to the starting point of the current forming layer to perform melting forming of titanium aluminum powder includes: The forming trajectory control PLC system positions the coaxial powder feeding electron gun to the starting point of the current forming layer by controlling the XY motion mechanism; The coaxial powder feeding electron gun outputs a circular electron beam to melt the titanium aluminum powder fed synchronously by the ultrasonic powder feeding barrel; After the titanium aluminum powder at the starting point is melted and formed, the forming trajectory control PLC system controls the XY motion mechanism to position the coaxial powder feeding electron gun to the next deposition point of the current forming layer; Until all the deposition points of the current forming layer are deposited and formed, the forming trajectory control PLC system stops the coaxial powder feeding electron gun from outputting the annular electron beam and the ultrasonic powder feeding barrel stops feeding the titanium aluminum powder.

5. The electron beam additive manufacturing method of titanium aluminum intermetallic compound according to claim 1, characterized in that: After positioning the coaxial powder feeding electron gun and the ultrasonic powder feeding barrel to the starting point of the current forming layer and melting and forming the titanium aluminum powder, the method further includes: The forming trajectory control PLC system transmits the forming completion signal of the current forming layer to the online temperature control system, and the online temperature control system calculates the height of the current forming part according to the slice thickness of the forming part; The first high-frequency scanning electron gun adjusts the scanning width of the first electron beam scanning area according to the height of the current formed part, and the second high-frequency scanning electron gun adjusts the scanning width of the second electron beam scanning area according to the height of the current formed part.

6. The electron beam additive manufacturing method of titanium aluminum intermetallic compound according to claim 1, characterized in that: The method of detecting the temperature of the forming area by using the first infrared thermal imager and the second infrared thermal imager to maintain the temperature within a preset temperature range and to make the temperature field uniformly distributed includes: The first infrared thermal imager and the second infrared thermal imager transmit the collected panoramic thermal images to the online temperature control system, and the online temperature control system analyzes the panoramic thermal images to obtain the temperature field distribution state on both sides of the formed part; The temperature fields on the two surfaces of the formed part are divided into multiple sub-areas. By controlling the residence time of the beams generated by different electron guns in different sub-areas on the corresponding surfaces of the formed part, the temperatures on both sides of the formed part are maintained within the preset temperature range and the temperature field is evenly distributed.

7. The electron beam additive manufacturing method of titanium aluminum intermetallic compound according to claim 1, characterized in that: The electron beam additive manufacturing system for titanium-aluminum intermetallic compounds also includes a Z-axis workbench; The method of controlling the coaxial powder feeding electron gun and the ultrasonic powder feeding barrel to melt and form the titanium aluminum powder of the next forming layer includes: The forming trajectory control PLC system controls the Z-axis worktable to move downward to slice thickness, retrieves the filling path information of the next forming layer, and transmits it to the current forming layer; Repeat the steps of melting and forming the titanium-aluminum powder for the current forming layer to complete the melting and forming of the titanium-aluminum powder for the next forming layer.

8. The electron beam additive manufacturing method of titanium aluminum intermetallic compound according to claim 1, characterized in that: After all the shaping layers of the shaped part are formed, the method further comprises: The online temperature control system enables the first high-frequency scanning electron gun and the second high-frequency scanning electron gun to output at the maximum beam power respectively, and perform high-frequency scanning in a defocused state, so that the scanning range covers the entire area of ​​the formed part, and keeps the temperature of the entire formed part within the preset temperature range for a certain period of time; gradually reducing the beam power output of the first high-frequency scanning electron gun and the second high-frequency scanning electron gun at a preset rate until it reaches zero; The online temperature control system turns off the power supply, the focusing unit, and the scanning coil current control unit of the first high-frequency scanning electron gun and the second high-frequency scanning electron gun; After the molded part and the metal substrate are naturally cooled to room temperature in a vacuum state, the molded part and the metal substrate are taken out.

9. An electron beam additive manufacturing system for titanium aluminum intermetallic compounds, characterized in that: An electron beam additive manufacturing method for realizing the titanium aluminum intermetallic compound according to any one of claims 1 to 8; The electron beam additive manufacturing system for titanium-aluminum intermetallic compounds comprises a coaxial powder feeding electron gun, an ultrasonic powder feeding barrel, a first infrared thermal imager, a second infrared thermal imager, a first high-frequency scanning electron gun, and a second high-frequency scanning electron gun.

10. The electron beam additive manufacturing system for titanium aluminum intermetallic compound according to claim 9, characterized in that: The first high-frequency scanning electron gun and the second high-frequency scanning electron gun both include a scanning coil current control unit, a power supply, and a focusing unit; The electron beam additive manufacturing system for titanium-aluminum intermetallic compounds also includes an online temperature control system, a forming trajectory control PLC system, an XY motion mechanism, and a Z workbench.

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