Device and method for rolling titanium / aluminum composite plate with laser-induced interface ripple morphology

Abstract

The invention belongs to the technical field of composite metal plate manufacturing, and particularly discloses a device and method for rolling a titanium / aluminum composite plate with a laser-induced interface ripple morphology. The technical problem that when the laminar metal composite material is prepared through an existing rolling composite method, holes, cracks and other defects are prone to occurring at the interface is solved. The device comprises a pair of flat rollers, a pair of pulse lasers is arranged on the incoming material side of the flat roller; the diffraction beam splitting element and the collimation focusing element scatter emergent light of the pulse laser into stripe-shaped light spots; and the pulse laser is subjected to pulse modulation, so that staggered irradiation of stripe-shaped light spots on the continuously moving plate can be realized. According to the method, on the basis of the thickening effect in laser bending forming and different thermal physical properties of titanium and aluminum, staggered and meshed macroscopic ripple shapes are generated on the interfaces of the two metal plates, namely the titanium alloy plate and the aluminum alloy plate, and a micro-area molten pool appears on the aluminum side; therefore, the double bonding phenomenon of mechanical bonding and metallurgical bonding of two metal interfaces is achieved, and the interface bonding performance is improved.

Description

Technical Field

[0001] This invention belongs to the field of composite metal plate manufacturing technology, and specifically discloses an apparatus and method for rolling titanium / aluminum composite plates with laser-induced interface ripple morphology. Background Technology

[0002] Aluminum alloys possess advantages such as low density and high strength. However, their strength and hardness significantly decrease at high temperatures. While the oxide film on the surface of aluminum alloys offers some protection, it is easily damaged in certain environments, leading to localized corrosion phenomena such as pitting and intergranular corrosion, thus affecting their service life and performance. Aluminum alloys are commonly used in the aerospace industry to manufacture load-bearing components for aircraft, but they are susceptible to localized corrosion from chloride ions and humidity, reducing lifespan and safety. WC-Co coatings are prone to peeling off in marine climates, offering limited protection. Titanium alloys are corrosion-resistant but expensive. Titanium / aluminum composite plates combine the advantages of both, with a thin titanium layer coated on the aluminum alloy surface, improving corrosion resistance while controlling costs, making them an ideal material for equipment operating in harsh environments.

[0003] Currently, methods for preparing metal composite plates include extrusion bonding, rolling bonding, diffusion welding, explosive bonding, and friction stir welding. Since rolling bonding is a commonly used method for preparing metal composite materials, enabling continuous and mass production of layered metal composites, it is the preferred method for preparing titanium / aluminum composite plates. However, traditional rolling bonding methods struggle to achieve sufficient interfacial bonding for dissimilar metals with significantly different mechanical properties, easily leading to interface cracking. This results in defects such as voids and cracks at the interface of the prepared layered metal composite material, severely reducing its mechanical and formability properties. Summary of the Invention

[0004] This invention addresses the technical problem that existing rolling composite methods for preparing layered metal composites are prone to causing cracking at the bonding interface, resulting in defects such as pores and cracks at the interface of the prepared layered metal composites. The invention provides an apparatus and method for rolling titanium / aluminum composite plates with laser-induced interface ripple morphology.

[0005] This invention is achieved using the following technical solution: an apparatus for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology, comprising at least a pair of flat rolls for rolling titanium / aluminum plates; a pair of first pulse lasers and second pulse lasers respectively arranged above and below the plate on the incoming side of the flat rolls; the first pulse laser located above has its emission end facing downward and an optical system is provided on its emission path, and the second pulse laser located below has its emission end facing upward and an optical system is also provided on its emission path; the optical system includes a diffraction beam splitting element and a collimating focusing element; the two optical systems respectively scatter the emission light from the first and second pulse lasers into striped light spots, constituting a laser irradiation area; the direction of the striped light spots is perpendicular to the rolling direction of the plate; pulse modulation of the first and second pulse lasers can achieve staggered irradiation of the striped light spots on the continuously moving plate.

[0006] This device enables a laser beam emitted by a pulsed laser to diverge into striped spots with equal spacing after passing through a diffraction beam splitter. By modulating the pulsed laser output parameters, two metal plates are subjected to non-uniform, staggered irradiation. Based on the thickening effect in laser bending and the different thermophysical properties of titanium and aluminum, a state of coexistence of macroscopic corrugated mechanical interlocking and microscopic metallurgical bonding is formed at the interface of the two metal plates, thus changing the load-bearing mode of the bonding interface.

[0007] Furthermore, it also includes a pair of graphite spraying devices located on the infeed side of the flat roll, respectively arranged above and below the sheet; the graphite spraying devices are located in front of the first pulse laser and the second pulse laser, and the pair of graphite spraying devices arranged above and below can spray a striped graphite coating on the outer surface of the sheet to enhance the laser absorption effect; the discharge side of the flat roll is provided with a graphite cleaning device for cleaning the graphite coating on the surface of the sheet.

[0008] Furthermore, the graphite spraying device uses a plasma graphite spray gun; the graphite cleaning device employs a pair of brush rollers.

[0009] This invention also discloses a method for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology, comprising the following steps: The thicknesses are respectively n 1 and n Two titanium alloy plates and an aluminum alloy plate are stacked on top of each other. Before entering the laser irradiation zone, a graphite spraying device is used to add an interlaced graphite coating in a staggered stripe pattern to the outer surfaces of the two alloy plates. The width of the graphite coating stripes on the outer surface of the titanium alloy plate is 2. n 1. The stripe spacing is 2. n 2. The width of the graphite coating stripes on the outer surface of the aluminum alloy plate is 2. n 2, the stripe spacing is 2 n 1; The interlaced stripes refer to the stripe spacing on one alloy plate corresponding to the stripe spacing on another alloy plate; The positions of the first and second pulse lasers and their corresponding optical systems were adjusted to ensure that the two striped laser spots intersect, meaning that the stripes of one striped laser spot correspond to the fringe spacing of the other striped laser spot; the fringe width of the striped laser spot on the outer surface of the titanium alloy plate is 0.1. n 1, the stripe spacing is 2 ( n 1+ n 2) The width of the striped light spots on the outer surface of the aluminum alloy plate is 0.1. n 2, the stripe spacing is 2 ( n 1+ n 2); The number of stripes in the striped light spot is N ; By modulating the output parameters of the pulsed laser, the substrate is subjected to continuous, non-uniform, staggered irradiation. The pulse frequencies of the first and second lasers are both... Hz, where, D The diameter of the flat roll is in mm. ω The rolling speed is expressed in revolutions per minute (rpm), and the pulse width is... W =100 / f ms; After being irradiated by a pulsed laser, the bimetallic plate expands and thickens at both the interface and the outer layer due to the thickening effect. The interface exhibits interlocking ripples. At the same time, due to the enhanced metal flow properties at high temperatures in the irradiated area and the high temperature of the titanium side, micro-layer melting occurs on the aluminum side of the interface, forming a micro-melt pool. Then, a flat roll rolling process is used for rolling composite, and titanium alloy plates and aluminum alloy plates are rolled in the rolling zone to obtain titanium / aluminum composite plates.

[0010] Furthermore, the first and second pulse lasers differ in phase (2) along the rolling direction when positioning the striped laser spot. n 1mm.

[0011] Furthermore, after the rolling process, the two metal plates are cleaned by a graphite cleaning device to remove the graphite coating from the plate surface to ensure the cleanliness of the plate surface.

[0012] Furthermore, the rolling zone is a wedge-shaped area formed by the mechanical bonding and metallurgical bonding of the interfaces of the titanium alloy plate and the aluminum alloy plate under the pressure of the flat rolling rolls.

[0013] The beneficial effects of this invention are: based on the thickening effect in laser bending forming and the different thermophysical properties of titanium and aluminum, the interface between the titanium alloy plate and the aluminum alloy plate produces a macroscopic corrugated morphology with interlocking, and a micro-melt pool appears on the aluminum side, so that the interface between the two metals achieves a dual bonding phenomenon of mechanical bonding and metallurgical bonding to improve the interface bonding performance. Attached Figure Description

[0014] Figure 1 A schematic diagram of the structure of the device for implementing the present invention; Figure 2 This is a schematic diagram of the spaced stripes on a titanium alloy plate. Figure 3 This is a schematic diagram of the spaced stripes on an aluminum alloy plate. Figure 4 This is a schematic diagram of the rolling device in this invention.

[0015] 1-Titanium alloy plate, 2-Aluminum alloy plate, 3-Graphite spraying device, 4-Optical system, 5-First pulse laser, 6-Second pulse laser, 7-Flat rolling roll, 8-Graphite cleaning device. Detailed Implementation

[0016] See Figure 1 A method for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology, comprising the following steps: Prepare two metal plates, titanium alloy plate 1 with a thickness of [missing information]. n 1mm, aluminum alloy plate 2 thickness is n A 2mm thick graphite coating is applied to the outer surfaces of two metal plates using a plasma graphite spray gun in a pre-positioned, intermittent spray pattern, forming staggered stripes. The stripe width on the titanium alloy plate side is 2mm. n 1mm, stripe spacing is 2 n 2mm, the width of the stripes on both sides of the aluminum alloy plate is 2 n 2mm, stripe spacing is 2 n 1mm. For example... Figure 2 , Figure 3 As shown, a plasma arc is used as a heat source to heat graphite powder to an extremely high temperature and melt it. The melted powder is then sprayed at high speed onto the surface of the workpiece to form a coating, thereby enhancing the laser absorption effect.

[0017] Two optical systems 4 are used to scatter stripe-shaped light spots of equal intervals from two pulsed lasers. The first pulsed laser 5 modulates a light spot with a width of 0.1. n 1mm, number of stripes is N The interval is 2 ( n 1+ n 2) mm, the beam width modulated by the second pulse laser 6 is 0.1 mm. n 2mm, number of stripes is N The interval is 2 ( n 1+ n 2) mm, by modulating the output parameters of the pulsed laser, the substrate is subjected to continuous, non-uniform, staggered irradiation, wherein the pulse frequencies of the first and second lasers are both Hz, where, D The diameter of the roll is in mm. ω The rolling speed is expressed in revolutions per minute (rpm), and the pulse width is...W =100 / f The unit is milliseconds. When the first pulse laser 5 and the second pulse laser 6 are positioning the rectangular stripe-shaped light spot, the phase difference along the rolling direction is 2. n The pulse width and rolling speed are coupled with the graphite stripes to ensure that the pulsed laser irradiates the graphite coating on the moving titanium alloy plate 1 and aluminum alloy plate 2 exactly.

[0018] After laser array irradiation, plastic deformation and thickening are simultaneously induced at the interface and surface of the titanium alloy plate 1 and aluminum alloy plate 2, resulting in a macroscopic corrugated morphology of interlocking at the metal plate interface. The temperature rises within the irradiation area, enhancing the fluidity of the metals. Due to the differences in thermophysical properties between titanium and aluminum (titanium has a relatively low thermal conductivity), heat accumulates on the titanium side under laser irradiation, causing a rapid increase in its temperature. Heat is conducted from the high-temperature titanium side to the aluminum side. When the temperature near the aluminum interface reaches its melting point, a micro-melt pool is formed, resulting in micro-layer melting on the aluminum side of the interface, thus creating a solid-phase structure at the bimetallic plate interface. After passing through the laser irradiation area, the two metal plates are fed by a feeding device to a wedge-shaped area formed by two flat rolls 7 for rolling and compounding. The feeding speed is... πDω / 60 mm / s, matching the rotational speed of the flat roll 7.

[0019] After rolling, the two metal sheets are cleaned by a graphite cleaning device 8 to remove the graphite coating from the sheet surface and ensure surface cleanliness. The graphite cleaning device 8 uses a brush roller with a diameter of 0.6 mm. D mm, rotation speed 2 ω Redirects / minutes.

[0020] In the specific embodiment of the composite plate, the upper side is a titanium alloy plate TC4 with a size of 200×100×1mm, and the lower side is an aluminum alloy plate 7075 with a size of 200×100×1mm. A staggered stripe graphite coating (the coating direction is perpendicular to the rolling direction) is added to the surfaces of the two metal plates using a plasma graphite spray gun. The stripe width is 2mm and the spacing is 2mm to ensure increased absorption efficiency under subsequent laser irradiation.

[0021] The two flat rolling rolls 7 have a diameter of 250 mm and a rotation speed of 10 r / min. The two metal plates are fed in by a feeding device at a speed of 131 mm / s, matching the rolling roll speed. The titanium alloy plate 1 and aluminum alloy plate 2 are fed into the irradiation range of the pulsed laser by the feeding device. The laser beam emitted by the pulsed laser is split into five independent beams by a diffraction beam splitter, and then focused into five beams by a collimating and focusing element (which can be a lens system). Each beam is a linear beam with a width of 0.1 mm and a length of 100 mm. The laser is pulse-modulated with a pulse width of 15.4 ms and a frequency of 6.5 Hz, so that the laser is output in the form of a pulse sequence. The output power of the laser is set to 6 kW on the titanium plate side and 2 kW on the aluminum plate side.

[0022] After passing through the laser irradiation zone, the titanium alloy plate 1 and aluminum alloy plate 2 are heated and expand. The surrounding cold material exerts pressure on them, causing the heated material to accumulate and the plates to thicken locally, resulting in a thickening effect. Therefore, the outer layer and interface of the two metal plates exhibit alternating corrugated morphology. Due to the differences in the thermophysical properties of titanium and aluminum, as well as the difference in laser power, the titanium side has a higher temperature than the aluminum side. Heat is conducted from the high-temperature titanium side to the aluminum side. When the temperature near the aluminum interface reaches near its melting point, a micro-melt pool is formed, manifesting as micro-layer melting on the aluminum side of the interface.

[0023] After passing through the laser irradiation zone, the two metal plates are fed by a feeding device to a wedge-shaped area formed by two flat rolling rolls 7 for rolling and compounding.

[0024] After the rolling process, the graphite coating on the surface of the two metal plates is cleaned by a brush roller (150mm in diameter, 20r / min) to ensure the cleanliness of the plate surface.

Claims

1. An apparatus for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology, comprising at least a pair of flat rolls (7) for rolling titanium / aluminum plates; characterized in that, A pair of first pulse lasers (5) and second pulse lasers (6) are respectively arranged on the upper and lower sides of the plate on the receiving side of the flat roll (7); the upper first pulse laser (5) has its emission end facing downward and an optical system (4) is provided on its emission path, and the lower second pulse laser (6) has its emission end facing upward and an optical system (4) is also provided on its emission path; the optical system (4) includes a diffraction beam splitting element and a collimation focusing element; the two optical systems (4) respectively scatter the emission light of the first and second pulse lasers into striped light spots, forming a laser irradiation area; the direction of the striped light spots is perpendicular to the rolling direction of the plate; pulse modulation of the first and second pulse lasers can realize the staggered irradiation of the striped light spots on the continuously moving plate.

2. The apparatus for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology as described in claim 1, characterized in that, It also includes a pair of graphite spraying devices (3) arranged on the upper and lower sides of the sheet on the incoming side of the flat roll (7); the graphite spraying devices (3) are located in front of the first pulse laser (5) and the second pulse laser (6), and the pair of graphite spraying devices (3) arranged on the upper and lower sides can spray an intermittent graphite coating on the outer surface of the sheet; the outgoing side of the flat roll (7) is provided with a graphite cleaning device (8) for cleaning the graphite coating on the surface of the sheet.

3. The apparatus for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology as described in claim 2, characterized in that, The graphite spraying device (3) uses a plasma graphite spray gun.

4. The apparatus for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology as described in claim 2, characterized in that, The graphite cleaning device (8) uses a pair of brush rollers.

5. A method for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology, comprising using the apparatus for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology as described in claim 2, characterized in that, Includes the following steps: The thicknesses are respectively n 1 and n Titanium alloy plate (1) and aluminum alloy plate (2) are stacked on top of each other. Before entering the laser irradiation area, a graphite spraying device (3) is used to add an interlaced graphite coating on the outer surface of the two alloy plates in the form of staggered stripes. The graphite coating stripe width on the outer surface of the titanium alloy plate (1) is 2. n 1. The stripe spacing is 2. n 2. The width of the graphite coating stripes on the outer surface of the aluminum alloy plate (2) is 2. n 2, the stripe spacing is 2 n 1; The interlaced stripes refer to the stripe spacing on one alloy plate corresponding to the stripe spacing on another alloy plate; The positions of the first and second pulse lasers and the corresponding optical system (4) are adjusted to ensure that the two striped light spots are staggered, that is, the stripes of one striped light spot correspond to the stripe spacing of the other striped light spot; the stripe width of the striped light spot on the outer surface of the titanium alloy plate (1) is 0.

1. n 1, the stripe spacing is 2 ( n 1+ n 2) The stripe width of the striped light spot on the outer surface of the aluminum alloy plate (2) is 0.

1. n 2, the stripe spacing is 2 ( n 1+ n 2); The number of stripes in the striped light spot is N ; By modulating the output parameters of the pulsed laser, the substrate is subjected to continuous, non-uniform, staggered irradiation. The pulse frequencies of the first and second lasers are both... Hz, where, D The diameter of the flat roll (7) is in mm. ω The rolling speed is expressed in revolutions per minute (rpm), and the pulse width is... W =100 / f ms; After being irradiated by a pulsed laser, the bimetallic plate expands and thickens at both the interface and the outer layer due to the thickening effect. The interface exhibits interlocking ripples. At the same time, due to the enhanced metal flow properties at high temperatures in the irradiated area and the high temperature of the titanium side, micro-layer melting occurs on the aluminum side of the interface, forming a micro-melt pool. Then, a flat roll rolling process is used for rolling composite, and titanium alloy plate (1) and aluminum alloy plate (2) are rolled in the rolling zone to obtain titanium / aluminum composite plate.

6. The method for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology as described in claim 5, characterized in that, When positioning the striped light spot, the first pulse laser (5) and the second pulse laser (6) are 2 pulses apart along the rolling direction. n 1mm.

7. The method for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology as described in claim 5 or 6, characterized in that, After the rolling process, the two metal plates are cleaned by a graphite cleaning device (8) to clean the graphite coating on the plate surface to ensure the cleanliness of the plate surface.

8. The method for rolling titanium / aluminum composite plates with laser-induced interfacial ripple morphology as described in claim 5 or 6, characterized in that, The rolling zone is a wedge-shaped area formed by the mechanical bonding and metallurgical bonding of the interfaces of the titanium alloy plate (1) and the aluminum alloy plate (2) under the pressure of the flat rolling roll (7).

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