A method for forming a titanium / magnesium layered composite shell having a three-dimensional interface structure

Abstract

The application provides a forming method of a titanium / magnesium layered composite shell with a three-dimensional interface structure, and belongs to the technical field of non-ferrous metal preparation. According to the physical, chemical, acoustic and electromagnetic performance characteristics of titanium alloy and magnesium alloy, the application adopts titanium alloy as an outer layer metal of the shell and magnesium alloy as an inner layer metal, processes a threaded groove structure on the inner surface of the outer layer titanium alloy in advance, and applies a high-energy ultrasonic field in a spinning forming process to control the plastic deformation of the metal and the residual stress in the shell, so that a three-dimensional occlusal interface of mechanical-metallurgical bonding is formed, and a titanium / magnesium layered composite shell with good forming performance is prepared.

Description

Technical Field

[0001] This invention belongs to the technical field of non-ferrous metal preparation, and specifically discloses a method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure. Background Technology

[0002] Titanium alloys possess excellent properties such as high strength, corrosion resistance, and high temperature resistance, making them widely used in aerospace, electronics, electrical engineering, and weaponry. However, their high price and density limit their applications to some extent. Magnesium alloys have low density, good electromagnetic shielding properties, and good mechanical properties, but their corrosion resistance is relatively poor. Combining the characteristics of titanium and magnesium alloys, a titanium / magnesium layered composite shell can be fabricated to overcome their respective shortcomings, showing broad application prospects.

[0003] During the plastic deformation process, the differences in strength, plasticity, and melting point between titanium / magnesium layered composite shells make it difficult to coordinate the plastic deformation. Furthermore, both titanium and magnesium alloys have poor plastic deformation capabilities at medium and low temperatures, and the heating temperature during deformation cannot reach the plastic deformation temperature of titanium alloys due to the limitation of magnesium alloy melting point. Therefore, an effective method is needed to prepare titanium / magnesium layered composite shells. Summary of the Invention

[0004] Based on the physical, chemical, acoustic, and electromagnetic properties of titanium and magnesium alloys, this invention uses titanium alloy as the outer shell metal and magnesium alloy as the inner shell metal. A threaded groove structure is pre-machined on the inner surface of the outer titanium alloy. A high-energy ultrasonic field is applied during the spinning process to regulate the plastic deformation of the metal and the residual stress inside the shell, forming a three-dimensional interlocking interface with mechanical-metallurgical bonding, thus producing a titanium / magnesium layered composite shell with good formability.

[0005] This invention provides a method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure, comprising the following steps:

[0006] S1, machining titanium alloy outer cylinder and magnesium alloy inner cylinder

[0007] The titanium alloy outer cylinder and the magnesium alloy inner cylinder are machined to the preset size. Threaded grooves are machined on the inner surface of the titanium alloy outer cylinder, and a step is machined at the first end of the magnesium alloy inner cylinder.

[0008] S2, the magnesium alloy inner cylinder is assembled into the titanium alloy outer cylinder, and the step at the first end of the magnesium alloy inner cylinder presses against the first end of the titanium alloy outer cylinder to form a titanium / magnesium assembly.

[0009] S3, High-energy ultrasound-assisted spinning forming of titanium / magnesium composite shell

[0010] The titanium / magnesium assembly prepared in step S2 is mounted on an internal spinning press and spun into shape, while being subjected to ultrasonic assistance.

[0011] S4, Residual stress control of the titanium / magnesium composite shell.

[0012] The titanium / magnesium composite shell prepared in step S3 is placed on a high-energy ultrasonic residual stress control test bench for residual stress control. Ultrasonic components are arranged along the axial direction of the titanium / magnesium composite shell at a preset interval. Each group of ultrasonic components includes multiple ultrasonic pressure heads arranged along the circumference of the titanium / magnesium composite shell.

[0013] S5, storage

[0014] Storage temperature: 20℃, relative humidity: ≤10%.

[0015] The internal spinning press used in step S3 includes an internal spinning press frame, a fixed frame, a sliding frame, a three-jaw chuck, an internal spinning press spindle, an internal spinning press motor, a retaining ring, an ultrasonic generator, a transducer, an amplitude transformer, an ultrasonic tool head, and a spinning head. The fixed frame and the sliding frame are arranged opposite to each other. The fixed frame is fixedly installed on the internal spinning press frame, and the sliding frame is slidably installed on the internal spinning press frame. The three-jaw chuck is installed on the fixed frame. The internal spinning press spindle is installed on the sliding frame and is coaxial with the three-jaw chuck. It is driven to rotate by the internal spinning press motor. A retaining ring is installed inside the internal spinning press spindle. The transducer is installed on the retaining ring and is coaxial with the internal spinning press spindle. Its input end is connected to the output end of the ultrasonic generator.

[0016] The input end of the amplitude transformer is connected to the output end of the transducer; the ultrasonic tool head passes through the spindle of the inner spinning machine, and its input end is connected to the output end of the amplitude transformer; the spinning head includes an inner ring and cylindrical rolling elements; the inner ring of the spinning head has a frustum-shaped structure, with its central hole connected to the output end of the ultrasonic tool head, its small end face facing the fixed frame, and its large end face facing the sliding frame; the cylindrical rolling elements surround the outer side of the inner ring of the spinning head, and its central axis is parallel to the outer wall of the inner ring of the spinning head;

[0017] Step S3 includes:

[0018] t1, clamp the second end of the titanium / magnesium assembly onto the three-jaw chuck, align the centerline of the titanium / magnesium assembly with the centerline of the spindle of the internal spinning press, and then position and clamp the titanium / magnesium assembly.

[0019] t2, start the internal spinning press, feed the spindle of the internal spinning press, and the ultrasonic tool head drives the cylindrical rolling body to spin the titanium / magnesium assembly while providing ultrasonic assistance.

[0020] In the aforementioned internal spinning press, the output end of the ultrasonic tool head is provided with a tool thread; the inner ring of the spinning head is fitted on the tool thread; the spinning head also includes a retainer, which passes through the cylindrical rolling element and has its two ends connected to the outer wall of the inner ring of the spinning head and the tool thread, respectively; a washer and a locking nut are fitted on the tool thread to press the retainer.

[0021] The aforementioned internal spinning press also includes an internal spinning press guide rail; the internal spinning press guide rail is mounted on the internal spinning press frame; the sliding frame is mounted on the internal spinning press guide rail; the internal spinning press is controlled by the internal spinning press electrical control cabinet.

[0022] The high-energy ultrasonic residual stress control test bench used in step S4 includes a support frame, ultrasonic components and an ultrasonic power supply; the ultrasonic components are arranged at a preset interval along the axial direction of the support frame, and each group of ultrasonic components includes multiple ultrasonic indenters arranged circumferentially along the support frame; the ultrasonic power supply provides power to the ultrasonic indenters.

[0023] Step S4 includes:

[0024] t1, Install the titanium / magnesium composite shell inside the support frame;

[0025] t2, turn on the ultrasonic pressure head to regulate the residual stress of the titanium / magnesium composite shell.

[0026] The aforementioned high-energy ultrasonic residual stress control test bench is controlled by the high-energy ultrasonic residual stress control test bench electrical control cabinet.

[0027] In step S1, the machining steps for the titanium alloy outer cylinder are as follows: clamp the titanium alloy outer cylinder on a lathe, turn the inner surface, the inner diameter is 94mm, the upper deviation is 0.1mm, and the lower deviation is 0.

[0028] Threaded grooves are machined on the inner surface of the titanium alloy outer cylinder. Depending on the different interfacial shear strength requirements, the depth of the threaded grooves is 0.1 to 0.5 mm and the pitch is 4 mm.

[0029] The machining steps for the magnesium alloy inner cylinder are as follows: clamp the magnesium alloy inner cylinder on a machine tool, turn the outer surface, the outer diameter is 94mm, the upper deviation is -0.05mm, the lower deviation is -0.15mm, and a step is machined at the first end, with an outer diameter of 106mm and a thickness of 4mm.

[0030] The inner wall of the magnesium alloy inner cylinder is machined to an inner diameter of 89mm, with an upper deviation of 0.1mm and a lower deviation of 0.

[0031] In step S3, the spindle speed of the internal spinning press is 500 r / min, the feed ratio is 1 mm / r, and multi-pass forming is adopted. The single-pass spinning deformation is within 20%. The total spinning deformation is 50% by changing different spinning heads between passes. The angles of the inner ring of the spinning head and the cylindrical rolling element are different in different spinning heads. The ultrasonic output power is 150 W and the frequency is 20 kHz.

[0032] In step S4, a set of ultrasonic components is arranged every 150 mm along the axial direction of the support frame, and an ultrasonic pressure head is arranged every 90° along the circumference of the support frame; the ultrasonic output power is 150 W and the frequency is 20 kHz.

[0033] The present invention has the following beneficial effects:

[0034] This invention addresses the advantages of high strength and corrosion resistance of titanium alloys and low cost of magnesium alloys by preparing a titanium / magnesium layered composite shell component that combines the properties of both. A pre-formed threaded groove structure on the inner surface of the titanium alloy outer cylinder creates a three-dimensional mechanical interlocking structure at the titanium-magnesium interface, improving interfacial shear strength. An ultrasonic field is applied to the spinning head during the internal spinning process, promoting deformation of the inner magnesium alloy layer and improving metal fluidity, facilitating the filling of the magnesium alloy into the threaded grooves. Subsequent manipulation using an array of high-energy ultrasonic fields enables the manufacture of a low-stress titanium / magnesium layered composite shell. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the titanium alloy outer cylinder.

[0037] Figure 2 for Figure 1 A magnified view of a portion of the image;

[0038] Figure 3 This is a schematic diagram of the magnesium alloy inner cylinder.

[0039] Figure 4 A schematic diagram of the spin forming process for a titanium / magnesium layered composite shell;

[0040] Figure 5 This is an assembly diagram of the ultrasonic generator, transducer, amplitude transformer, ultrasonic tool head, and spinning head in an internal spinning press.

[0041] Figure 6A schematic diagram of residual stress control for a titanium / magnesium composite shell;

[0042] Figure 7 A schematic diagram of a titanium / magnesium layered composite shell with a three-dimensional interface structure;

[0043] Figure 8 for Figure 7 A magnified view of a portion of the image.

[0044] In the diagram: 101-Internal spinning press frame; 102-Internal spinning press guide rail; 103-Fixed frame; 104-Sliding frame; 105-Three-jaw chuck; 106-Internal spinning press spindle; 107-Internal spinning press motor; 108-Fixed ring; 109-Ultrasonic generator; 110-Transducer; 111-Amplitude rod; 112-Ultrasonic tool head; 113-Spinning head inner ring; 114-Cage; 115-Cylindrical rolling element; 116-Washer; 117-Locking nut; 118-Internal spinning press... Electromechanical control cabinet; 119-Power switch for internal spinning press; 120-Power indicator light for internal spinning press; 121-Spindle control switch; 122-Spindle control switch indicator light; 123-Power switch I for ultrasonic generator; 124-Power indicator light I for ultrasonic generator; 125-Ultrasonic power control knob I; 126-Ultrasonic power control indicator light I; 127-Ultrasonic amplitude control knob I; 128-Ultrasonic amplitude control indicator light I; 129-Display screen for internal spinning press; 130-Flange;

[0045] 201-Stand; 202-Support frame; 203-Ultrasonic power supply; 204-Ultrasonic indenter; 205-Electrical control cabinet of high-energy ultrasonic residual stress control test bench; 206-Switch of high-energy ultrasonic residual stress control test bench; 207-Power switch indicator light of high-energy ultrasonic residual stress control test bench; 208-Power switch II of ultrasonic generator; 209-Power indicator light II of ultrasonic generator; 210-Ultrasonic power control knob II; 211-Ultrasonic power control indicator light II; 212-Ultrasonic amplitude control knob II; 213-Ultrasonic amplitude control indicator light II; 214-Display screen of high-energy ultrasonic residual stress control test bench; 215-Terminal; 216-Wire.

[0046] 301 - Titanium alloy outer cylinder; 302 - Magnesium alloy inner cylinder. Detailed Implementation

[0047] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] The bonding interfaces of layered composite metals typically take the form of mechanical interlocking, metallurgical bonding, and mechanical-metallurgical composite interfaces. These interfaces are typically flat and two-dimensional, and brittle intermetallic compounds easily form at the interface, reducing the interfacial bonding strength. Transforming the interface from a two-dimensional to a three-dimensional interlocking interface is beneficial for improving the shear strength of the interface. Applying a high-energy external field during the forming process is beneficial for the plastic deformation of the metal and increases its fluidity.

[0049] This embodiment employs ultrasonic-assisted spinning technology to prepare a layered composite shell of titanium (outer layer) / magnesium (inner layer). Before spinning, threaded grooves are machined inside the outer titanium alloy shell. During spinning, magnesium alloy is filled into the threaded grooves to form a three-dimensional interface. A high-energy ultrasonic field is fixedly applied to the surface of the outer titanium alloy to regulate the residual stress and metal fluidity inside the shell, thereby achieving high-quality titanium / magnesium layered composite shell spinning.

[0050] The raw materials used are: titanium alloy tubes, magnesium alloy tubes, sandpaper, and alcohol, and their quantities are as follows: measured in pieces, millimeters, and sheets.

[0051]

[0052] The internal spinning press includes an internal spinning press frame 101, an internal spinning press guide rail 102, a fixed frame 103, a sliding frame 104, a three-jaw chuck 105, an internal spinning press spindle 106, an internal spinning press motor 107, a retaining ring 108, an ultrasonic generator 109, a transducer 110, an amplitude transformer 111, an ultrasonic tool head 112, and a spinning head; the internal spinning press guide rail 102 is mounted on the internal spinning press frame 101; the fixed frame 103 and the sliding frame 104 are arranged opposite to each other, and the fixed frame 103 is fixed... The internal spinning press is fixedly mounted on the frame 101, and the sliding frame 104 is mounted on the internal spinning press guide rail 102; the three-jaw chuck 105 is mounted on the fixed frame 103; the first end of the internal spinning press main shaft 106 is mounted on the sliding frame 104, and the second end is mounted on the flange 130 by bolts and nuts. The internal spinning press main shaft 106 and the three-jaw chuck 105 are coaxially arranged and driven to rotate by the internal spinning press motor 107; a retaining ring 108 is installed inside the internal spinning press main shaft 106; the transducer 110 is installed. Mounted on the retaining ring 108, coaxially arranged with the spindle 106 of the internal spinning press, the input end of which is connected to the output end of the ultrasonic generator 109; the input end of the amplitude transformer 111 is connected to the output end of the transducer 110; the ultrasonic tool head 112 passes through the spindle 106 and flange 130 of the internal spinning press, the input end of which is connected to the output end of the amplitude transformer 111, and the output end is provided with a tool thread; the spinning head includes an inner ring 113, a cage 114, and cylindrical rolling elements 115; the inner ring 113 of the spinning head is circular. The structure is truncated, with a central hole connected to the tool thread of the ultrasonic tool head 112. The small end face faces the fixed frame 103, and the large end face faces the sliding frame 104. The cylindrical rolling element 115 surrounds the outer side of the inner ring 113 of the spinning head, with the central axis parallel to the outer wall of the inner ring 113 of the spinning head. The retainer 114 passes through the cylindrical rolling element 115, and its two ends are respectively connected to the outer wall of the inner ring 113 of the spinning head and the tool thread. A washer 116 and a locking nut 117 are fitted on the tool thread to press the retainer 114.

[0053] The internal spinning press is controlled by the internal spinning press electrical control cabinet 118. The internal spinning press electrical control cabinet 118 is equipped with an internal spinning press power switch 119, an internal spinning press power switch indicator light 120, a spindle control switch 121, a spindle control switch indicator light 122, an ultrasonic generator power switch I 123, an ultrasonic generator power indicator light I 124, an ultrasonic power control knob I 125, an ultrasonic power control indicator light I 126, an ultrasonic amplitude control knob I 127, an ultrasonic amplitude control indicator light I 128, and an internal spinning press display screen 129.

[0054] The high-energy ultrasonic residual stress control test bench includes a frame 201, a support frame 202, ultrasonic components, and an ultrasonic power supply 203. The support frame 202 is mounted on the frame 201. The ultrasonic components are arranged along the axial direction of the support frame 202 at a preset interval. Each group of ultrasonic components includes multiple ultrasonic indenters 204 arranged circumferentially along the support frame 202. The ultrasonic power supply 203 provides power to the ultrasonic indenters 204.

[0055] The aforementioned high-energy ultrasonic residual stress control test bench is controlled by the high-energy ultrasonic residual stress control test bench electrical control cabinet 205. The electrical control cabinet 205 is equipped with a high-energy ultrasonic residual stress control test bench switch 206, a high-energy ultrasonic residual stress control test bench power switch indicator light 207, an ultrasonic generator power switch II 208, an ultrasonic generator power indicator light II 209, an ultrasonic power control knob II 210, an ultrasonic power control indicator light II 211, an ultrasonic amplitude control knob II 212, an ultrasonic amplitude control indicator light II 213, a high-energy ultrasonic residual stress control test bench display screen 214, and terminal blocks 215. The ultrasonic indenter 204 is connected to the terminal blocks 215 via a wire 216.

[0056] The method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure provided in this embodiment includes the following steps.

[0057] S1, Machining the titanium alloy outer cylinder 301 and the magnesium alloy inner cylinder 302

[0058] The machining steps for the titanium alloy outer cylinder 301 are as follows: clamp the titanium alloy outer cylinder 301 on a lathe and machine the inner surface. The inner diameter is 94mm, the upper deviation is 0.1mm, and the lower deviation is 0.

[0059] Threaded grooves are machined on the inner surface of the titanium alloy outer cylinder 301. Depending on the different interface shear strength requirements, the depth of the threaded groove is 0.1 to 0.5 mm and the pitch is 4 mm.

[0060] The machining steps of the magnesium alloy inner cylinder 302 are as follows: clamp the magnesium alloy inner cylinder 302 on the machine tool, turn the outer surface, the outer diameter is 94mm, the upper deviation is -0.05mm, the lower deviation is -0.15mm, and a step is machined at the first end, with an outer diameter of 106mm and a thickness of 4mm.

[0061] The inner wall of the magnesium alloy inner cylinder 302 is machined to an inner diameter of 89 mm, with an upper deviation of 0.1 mm and a lower deviation of 0 mm.

[0062] S2, the magnesium alloy inner cylinder 302 is assembled into the titanium alloy outer cylinder 301 to form a titanium / magnesium assembly. The step at the first end of the magnesium alloy inner cylinder 302 presses against the first end of the titanium alloy outer cylinder 301 for positioning, while preventing coolant from entering the connection interface and affecting the interface connection performance.

[0063] S3, High-energy ultrasound-assisted spinning forming of titanium / magnesium composite shell

[0064] t1, clamp the second end of the titanium / magnesium assembly onto the three-jaw chuck 105, so that the center line of the titanium / magnesium assembly coincides with the center line of the spindle 106 of the internal spinning press. After adjustment, position and clamp the titanium / magnesium assembly.

[0065] t2, start the internal spinning press, feed the spindle 106 of the internal spinning press, and the ultrasonic tool head 112 drives the cylindrical rolling element 115 to spin the titanium / magnesium assembly while providing ultrasonic assistance. The spindle 106 of the internal spinning press rotates at 500 r / min, the feed ratio is 1 mm / r, and multi-pass forming is adopted. The single-pass spinning deformation is within 20%. The total spinning deformation is 50% by changing different spinning heads between passes. The angles of the inner ring 113 of the spinning head and the cylindrical rolling element 115 are different in different spinning heads. The ultrasonic output power is 150 W and the frequency is 20 kHz.

[0066] t3, After spinning is completed, turn off the inner spinning press and remove the spun titanium / magnesium composite shell.

[0067] S4, Residual stress control of the titanium / magnesium composite shell.

[0068] t1, the titanium / magnesium composite shell is installed in the support frame 202; a set of ultrasonic components is arranged every 150mm along the axial direction of the support frame 202, and an ultrasonic pressure head 204 is arranged every 90° along the circumference of the support frame to form an array-type control.

[0069] t2, turn on the ultrasonic pressure head 204 to adjust the residual stress of the titanium / magnesium composite shell. The ultrasonic output power is 150w, the frequency is 20kHz, and the adjustment time is 20min. Different time and power can be adjusted according to the specific residual stress requirements.

[0070] t3, shut down the high-energy ultrasonic residual stress control test bench, complete the residual stress control inside the titanium / magnesium composite shell, remove the titanium / magnesium composite shell, and complete the preparation.

[0071] S5, storage

[0072] The prepared titanium / magnesium composite shell is packaged with soft material and stored in a clean, dry environment, protected from moisture, sunlight, and acid, alkali and salt corrosion. The storage temperature is 20℃ and the relative humidity is ≤10%.

[0073] Conclusion: The shell uses titanium alloy as the outer layer material and magnesium alloy as the inner layer material to achieve the goal of lightweight, high strength and corrosion resistance. The pre-fabricated threaded groove structure on the inner wall of the titanium alloy realizes the three-dimensional mechanical interlocking interface between titanium and magnesium, which increases the interfacial bonding shear strength. During the internal spinning process, high-energy ultrasonic waves are applied to the cylindrical rolling element 115 to promote the plastic flow of the inner magnesium alloy and reduce the deformation resistance. After spinning, the stress is controlled by the high-energy ultrasonic energy field to reduce the residual stress inside the shell and prevent the shell from deforming due to residual stress. A high-quality titanium / magnesium layered composite shell is prepared.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure, characterized in that, Includes the following steps: S1, machining titanium alloy outer cylinder and magnesium alloy inner cylinder The titanium alloy outer cylinder and the magnesium alloy inner cylinder are machined to the preset size. Threaded grooves are machined on the inner surface of the titanium alloy outer cylinder, and a step is machined at the first end of the magnesium alloy inner cylinder. S2, the magnesium alloy inner cylinder is assembled into the titanium alloy outer cylinder, and the step at the first end of the magnesium alloy inner cylinder presses against the first end of the titanium alloy outer cylinder to form a titanium / magnesium assembly. S3, High-energy ultrasound-assisted spinning forming of titanium / magnesium composite shell The titanium / magnesium assembly prepared in step S2 is mounted on an internal spinning press and spun into shape, while being subjected to ultrasonic assistance. The internal spinning press used in step S3 includes an internal spinning press frame, a fixed frame, a sliding frame, a three-jaw chuck, an internal spinning press spindle, an internal spinning press motor, a fixed ring, an ultrasonic generator, a transducer, an amplitude transformer, an ultrasonic tool head, and a spinning head. The fixed frame and the sliding frame are arranged opposite to each other. The fixed frame is fixedly installed on the frame of the inner spinning press, and the sliding frame is slidably installed on the frame of the inner spinning press. The three-jaw chuck is mounted on a fixed frame; The main shaft of the internal spinning press is mounted on the sliding frame and is coaxially arranged with the three-jaw chuck. It is driven to rotate by the internal spinning press motor. A retaining ring is installed inside the main shaft of the internal spinning press; The transducer is mounted on a fixed ring and is coaxially arranged with the main shaft of the internal spinning press. Its input end is connected to the output end of the ultrasonic generator. The input end of the amplitude transformer is connected to the output end of the transducer; The ultrasonic tool head passes through the main shaft of the internal rotary press, and its input end is connected to the output end of the amplitude transformer. The spinning head includes a spinning head inner ring and a cylindrical rolling element; The inner ring of the spinning head is a frustum-shaped structure, with the central hole connected to the output end of the ultrasonic tool head. The small end face faces the fixed frame, and the large end face faces the sliding frame. The cylindrical rolling element surrounds the outer side of the inner ring of the spinning head, and the central axis is parallel to the outer wall of the inner ring of the spinning head. Step S3 includes: t1, clamp the second end of the titanium / magnesium assembly onto the three-jaw chuck, align the centerline of the titanium / magnesium assembly with the centerline of the spindle of the internal spinning press, and then position and clamp the titanium / magnesium assembly. t2, start the internal spinning press, feed the spindle of the internal spinning press, and the ultrasonic tool head drives the cylindrical rolling body to spin the titanium / magnesium assembly while providing ultrasonic assistance; S4, Residual stress control of the titanium / magnesium composite shell. The titanium / magnesium composite shell prepared in step S3 is placed on a high-energy ultrasonic residual stress control test bench for residual stress control. Ultrasonic components are arranged along the axial direction of the titanium / magnesium composite shell at a preset interval. Each group of ultrasonic components includes multiple ultrasonic pressure heads arranged circumferentially along the titanium / magnesium composite shell.

2. The method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure according to claim 1, characterized in that, The output end of the ultrasonic tool head is provided with a tool thread; The inner ring of the spinning head is fitted onto the tool thread; The spinning head also includes a cage that passes through the cylindrical rolling element and has its two ends connected to the outer wall of the inner ring of the spinning head and the tool thread, respectively. The tool thread is fitted with a washer and a lock nut to compress and retain the retainer.

3. The method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure according to claim 2, characterized in that, The internal spinning press also includes an internal spinning press guide rail; The internal spinning press guide rail is mounted on the internal spinning press frame; The sliding frame is mounted on the guide rail of the internal spinning press; The internal spinning press is controlled by the internal spinning press electrical control cabinet.

4. The method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure according to any one of claims 1-3, characterized in that, The high-energy ultrasonic residual stress control test rig used in step S4 includes a support frame, ultrasonic components, and an ultrasonic power supply. The ultrasonic components are arranged at a preset interval along the axial direction of the support frame, and each group of ultrasonic components includes multiple ultrasonic pressure heads arranged circumferentially along the support frame. The ultrasonic power supply provides power to the ultrasonic indenter; Step S4 includes: t1, Install the titanium / magnesium composite shell inside the support frame; t2, turn on the ultrasonic pressure head to regulate the residual stress of the titanium / magnesium composite shell.

5. The method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure according to claim 4, characterized in that, The high-energy ultrasonic residual stress control test bench is controlled by the high-energy ultrasonic residual stress control test bench electrical control cabinet.

6. The method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure according to claim 5, characterized in that, In step S1, the machining steps for the titanium alloy outer cylinder are as follows: clamp the titanium alloy outer cylinder on a lathe, turn the inner surface, the inner diameter is 94mm, the upper deviation is 0.1mm, and the lower deviation is 0. Threaded grooves are machined on the inner surface of the titanium alloy outer cylinder. Depending on the different interfacial shear strength requirements, the depth of the threaded grooves is 0.1 to 0.5 mm and the pitch is 4 mm. The machining steps for the magnesium alloy inner cylinder are as follows: clamp the magnesium alloy inner cylinder on the machine tool, turn the outer surface, the outer diameter is 94mm, the upper deviation is -0.05mm, the lower deviation is -0.15mm, and a step is machined at the first end, with an outer diameter of 106mm and a thickness of 4mm. The inner wall of the magnesium alloy inner cylinder is machined to an inner diameter of 89 mm, with an upper deviation of 0.1 mm and a lower deviation of 0 mm.

7. The method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure according to claim 6, characterized in that, In step S3, the spindle speed of the internal spinning press is 500 r / min, the feed ratio is 1 mm / r, and multi-pass forming is adopted. The single-pass spinning deformation is within 20%. The total spinning deformation is 50% by changing different spinning heads between passes. The angles of the inner ring of the spinning head and the cylindrical rolling element are different in different spinning heads. The ultrasonic output power is 150W and the frequency is 20kHz.

8. The method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure according to claim 7, characterized in that, In step S4, a set of ultrasonic components is arranged every 150 mm along the axial direction of the support frame, and an ultrasonic pressure head is arranged every 90° along the circumference of the support frame. The ultrasonic output power is 150W and the frequency is 20kHz.

9. The method for forming a titanium / magnesium layered composite shell with a three-dimensional interface structure according to claim 8, characterized in that, Including step S5, storage Storage temperature: 20℃, relative humidity: ≤10%.

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