Low-melting-point liquid alloy suitable for 3D printing and 3D printing shaping method of low-melting-point liquid alloy

Abstract

The invention provides a low-melting-point liquid alloy suitable for 3D printing and a 3D printing shaping method of the low-melting-point liquid alloy. According to the liquid alloy provided by the invention, a multi-element eutectic phase can be provided through eutectic atoms formed among gallium, indium, tin and blended powder, so that the melting point of the titanium alloy is remarkably reduced. And after the material is injected to a target position, shaping and curing from outside to inside can be realized by directly utilizing an air cooling mode, so that a self-defined 3D printing metal structure is obtained. According to the alloy, in the cooling and curing process, cooling air columns sprayed at different angles can also be used for applying pressure to metal liquid drops, and adjustment forming of a metal shape structure at the printing operation position is achieved. 3D printing of the metal material can be achieved in a liquid phase mode, compared with a traditional alloy powder sintering and curing printing mode, pores and defects of a forming material can be effectively reduced, the printed metal structure is smoother and more compact, and therefore the richer surface effect is achieved, and application to subsequent machining and test scenes is facilitated.

Description

Technical Field

[0001] The present application relates to the field of intelligent manufacturing, and specifically to a low-melting-point liquid alloy suitable for 3D printing and a 3D printing shaping method thereof. Background Art

[0002] The substrate of a 3D printing device is generally made of polymer materials or metal powder. When using a polymer substrate, the printing needle stacks the molten polymer substrate layer by layer to the appropriate position to gradually construct it into a target structure. When using metal powder materials, existing printing equipment needs to rely on lasers or electron beams to melt the metal powder, thereby constructing the target structure layer by layer.

[0003] The structural strength and stress response characteristics of polymer substrates are significantly different from those of metal materials. The model structure constructed by them requires complex conversion work to obtain reference results when simulating mechanical or electrical properties. Metal powder substrates will partially vaporize during the melting process, and the gas flow generated during the vaporization process will wash away part of the powder, so tiny pores and defects are often generated in the structural molding material. When used for testing, large errors will also occur due to material defects.

[0004] Therefore, there is an urgent need for a 3D printing technology that can overcome the above-mentioned defects. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present application provides a low-melting-point liquid alloy suitable for 3D printing and a 3D printing shaping method thereof. The present application uses gallium, indium, tin and a proportioned blended powder to provide a multi-element eutectic phase in a titanium alloy, which can significantly reduce the melting point of the titanium alloy so that it can be injected into the target position at a constant temperature above 150°C and solidified by air cooling to obtain a 3D printed metal structure. The present application specifically adopts the following technical solutions.

[0006] First, in order to achieve the above-mentioned purpose, a low-melting-point liquid alloy suitable for 3D printing is proposed, which is prepared according to the following steps: step 1, heating gallium, indium, tin, blended powder and titanium alloy powder in a mass ratio of 27.2-38.3:4.8-8.8:3.5-5.8:3.7-8.8:43-60 under vacuum or protective atmosphere until completely melted; step 2, shaking the melted mixture until the melt is uniform, and then injecting it into the substrate pipeline of the 3D printer, so that the 3D printer can inject the substrate in the pipeline into the corresponding printing position according to the requirements of the printing model under a constant temperature of more than 150°C, thereby cooling layer by layer to obtain the target model; wherein the blended powder is magnesium powder or a mixture of magnesium powder and any one of the following metal powders: zinc or cadmium; the titanium alloy powder includes titanium powder accounting for more than 90% by mass.

[0007] Optionally, in any of the above described low-melting-point liquid alloys suitable for 3D printing, the titanium alloy powder further comprises: titanium chloride and / or titanium diboride powder.

[0008] Optionally, in any of the above described low-melting-point liquid alloys suitable for 3D printing, the mixed powder includes magnesium powder and zinc powder in a mass ratio of 1:1 to 3.

[0009] Optionally, in any of the above described low-melting-point liquid alloys suitable for 3D printing, the mixed powder includes magnesium powder and cadmium powder in a mass ratio of 1:1 to 3.

[0010] Optionally, in any of the above described low-melting-point liquid alloys suitable for 3D printing, the particle size of the gallium, indium, tin and mixed powders is in the range of 0.5 to 1 mm; the d50 particle size of the titanium alloy powder is in the range of 0.5 to 2 mm.

[0011] Optionally, a low-melting-point liquid alloy suitable for 3D printing as described above, wherein the liquid alloy is composed of gallium, indium, tin, magnesium, zinc, titanium, titanium chloride, and titanium diboride, and the mass ratio thereof is 35.3:8.3:5.2:3:3:56:1:1.

[0012] Optionally, the low-melting-point liquid alloy suitable for 3D printing as described above, wherein the 3D printer injects the substrate in the copper inner wall pipe into the printing needle of the printer according to the requirements of the printing model under a constant temperature of 160~180°C.

[0013] At the same time, in order to achieve the above-mentioned purpose, the present application also provides a shaping method of low-melting-point liquid alloy suitable for 3D printing, which is used for any of the liquid alloys described above, and the steps include: when the liquid alloy is injected into the corresponding printing position through the printing needle, a dry gas column with a temperature lower than room temperature is simultaneously sprayed toward the printing position from different directions, and the gas column cools the alloy droplets from the outside and shapes them by using the air flow pressure during the cooling and shaping process.

[0014] Optionally, in any of the above methods for shaping low-melting-point liquid alloys suitable for 3D printing, before the liquid alloy is injected into the printing needle, the temperature of the liquid alloy in the pipeline is controlled at a constant temperature of more than 150°C.

[0015] Optionally, a shaping method for a low-melting-point liquid alloy suitable for 3D printing as described above, wherein the gas column is pre-pressurized to a pressure of 1.2 to 2 times the ambient air pressure, and during the injection of the gas column, medium powder is blown to the printing position, and the medium powder is powder particles formed by crushing the liquid alloy after solidification, or the medium powder is a mixed powder particle of titanium alloy powder and carbon and / or manganese. Beneficial Effects

[0016] The low-melting-point liquid alloy suitable for 3D printing and its 3D printing shaping method provided by the present application. The liquid alloy provided by the present application can provide a five-element eutectic phase or even a six-element eutectic phase in the alloy through the eutectic atomic pairs formed between gallium, indium, tin and the blended powder, thereby significantly reducing the melting point of the titanium alloy. The liquid alloy of the present application has a melting point between 110°C and 140°C, a liquidus temperature between 170°C and 180°C, a melting width substantially greater than 50°C, and an effective optimization of the symmetry of the melting peak. Injecting it into the target position at a constant temperature of more than 150°C can directly use air cooling to achieve shaping and solidification from the outside to the inside, thereby obtaining a customized 3D printed metal structure. The alloy of the present application can also use cooling gas columns sprayed at different angles to pressurize the metal droplets during the cooling and solidification process to achieve adjustment and molding of the metal shape structure at the printing operation position. The present application can realize 3D printing of metal materials in liquid phase. Compared with the traditional printing method of sintering and solidifying alloy powder, it can effectively reduce the porosity and defects of the molding material, making the printed metal structure smoother and denser, thereby achieving richer surface effects and facilitating the application of subsequent processing and test scenarios.

[0017] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings: Figure 1 This is a DSC test result diagram of the low melting point liquid alloy suitable for 3D printing of the present application; Figure 2 It is a schematic diagram of the operating principle of a 3D printing device using the liquid alloy of the present application as a printing substrate; Figure 3 It is a schematic diagram of the cold air nozzle end structure in the device of the present application.

[0019] In the figure, 1 represents a sealed chamber; 2 represents a cold air nozzle; 3 represents a printing needle; 11 represents a turntable; 12 represents a medium powder spraying port; 21 represents a rotating guide groove; 22 represents an airflow guide device; 24 represents a limit strip; and 23 represents a rib. DETAILED DESCRIPTION

[0020] In order to make the purpose and technical solution of the embodiment of the present application clearer, the technical solution of the embodiment of the present application will be clearly and completely described in conjunction with the drawings of the embodiment of the present application. Obviously, the described embodiment is a part of the embodiment of the present application, not all of the embodiments. Based on the described embodiment of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0022] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0023] The meaning of "inside" and "outside" mentioned in this application refers to the direction pointing to the center of the air flow channel inside the cold air nozzle itself, and the opposite direction is outside; it is not a specific limitation on the device mechanism of this application.

[0024] The meaning of "left and right" in this application refers to that when the user is facing the sealed cavity, the left side of the user is left and the right side of the user is right, rather than a specific limitation on the device mechanism of this application.

[0025] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0026] The meaning of "up" and "down" in the present application refers to that when the user is facing the sealing chamber, the direction from the turntable to the printing needle is up, and the opposite direction is down, rather than a specific limitation on the device mechanism of the present application.

[0027] The purpose of the present invention is to provide a low melting point liquid alloy suitable for 3D printing. Based on the eutectic phase diagram strategy, the present invention uses the eutectic atomic pair principle and the deep eutectic point provided by the powder blending to design a five-element alloy component Ti58Ga38In8Sn5Mg4.8, whose melting point is reduced to below 150°C and the liquidus temperature is about 160°C. It can maintain liquid flow at a tube temperature of 160~180°C in the 3D printing device, and cool and shape at an appropriate speed during the cooling process of low-temperature dry gas columns sprayed from different directions. It can not only use the airflow pressure to effectively shape it during the cooling process, but also strictly limit the cooling time to improve printing efficiency.

[0028] On the basis of the above-mentioned five-element alloy, the present application can further form a six-element eutectic alloy by adding 4% by mass of Zn element, further reducing its melting point to about 140°C to facilitate droplet processing.

[0029] Furthermore, the present application can also replace the Zn element component in the above-mentioned quinary alloy Ti58Ga38In8Sn5Mg4.8Zn4 in combination with the Mg50Cd50 (at%) phase diagram, and further adjust the melting point temperature and liquidus temperature by adjusting the Cd element ratio content in the formulated powder. Example

[0030] The liquid alloy in this embodiment is Ti43Ga27.2In8.3Sn5.5Mg3, which can be prepared by the following steps: (1) Strictly weigh the samples of each element according to the required proportion, mix the samples evenly and place them in a sealed container; (2) Evacuate the sealed container to make the internal pressure of the container lower than 1×10-2Pa, close the vacuum valve, and introduce high-purity argon gas. Repeat the above operation three times and then heat the container to completely melt the sample. (3) Shake the container for more than half an hour until the melted mixture in the container reaches a uniform molten state, thus obtaining liquid alloy.

[0031] According to DSC testing, the melting point of the liquid alloy is about 130°C, which makes it suitable for temperature control pipeline systems with working temperatures above 150°C in 3D printing. Example

[0032] The mass ratio of gallium, indium, tin, magnesium and titanium contained in the alloy in the previous embodiment is adjusted to 38.3:8.8:5.2:3:60. The preparation method is the same as that in Example 1. A metal substrate with a melting point of about 140°C is obtained. The metal substrate is passed into the temperature control pipeline system of the 3D printing device and can also be solidified by air cooling to achieve a three-dimensional printing effect. Example

[0033] The mass ratio of gallium, indium, tin, magnesium and titanium in the previous embodiment is adjusted to 35.3:4.8:3.5:3:58. The preparation method is the same as that in Example 1. A metal substrate with a melting point close to 120° C. is obtained, which is then passed into the temperature control pipeline system of the 3D printing device for printing.

[0034] Taking into account the inevitable temperature loss that will occur in the process of the metal substrate flowing from the temperature control pipeline system of the 3D printing equipment to the tip of the printing needle 3, the present application preferably considers lowering the melting point of the liquid alloy as much as possible so that it can still have appropriate fluidity during the cooling process at the printing position, so as to achieve shaping and solidification through air cooling. Example

[0035] Zn is further added on the basis of the previous embodiment, and the melting point of the alloy material is further controlled by the crystal phase coordination between Zn and Mg. In this embodiment, the mass ratio of gallium, indium, tin, magnesium, zinc, and titanium is adjusted to 35.3:8.3:5.8:1.9:1.8:58, and the preparation method is the same as that of Example 1, to obtain a metal substrate with a melting point temperature slightly lower than 120°C, which is suitable for being supplied to the printing needle 3 of the 3D printing device through a temperature control pipeline system so as to be accurately applied to a suitable working position for printing. Example

[0036] Based on the previous embodiment, Zn is further replaced with Cd to try to regulate the melting point of the alloy material. In this embodiment, the mass ratio of gallium, indium, tin, magnesium, cadmium, and titanium is adjusted to 35.3:8.3:5.2:2.2:4-6.6:58, wherein the titanium element component specifically includes: 90% by mass of titanium powder and 10% by mass of titanium chloride. The above powder is melted and shaken in the same manner as in Example 1 to obtain a metal substrate with a melting point temperature between 110°C and 120°C.

[0037] During the preparation process, considering the heating efficiency of the material and the oscillation mixing efficiency, it is preferred to control the particle size of each metal powder between 0.5 and 2.5 mm. Gallium, indium, tin, and the blended powders composed of magnesium, cadmium or magnesium and zinc can be set to a smaller particle size in order to fully mix them with other components of the titanium alloy powder. As a result, powders with smaller particle sizes can be evenly distributed in the gaps between the titanium alloy powder particles, making it easier to oscillate after heating and melting to form a uniformly molten metal substrate. Example

[0038] Based on the above embodiment, the mass ratio of gallium, indium, tin, magnesium, zinc and titanium components is further adjusted to 35.3:8.3:5.2:3:3:58, wherein the titanium component can be specifically composed of titanium powder, titanium chloride and titanium diboride in a mass ratio of 56:1:1. In addition, it is preferred that the particle size range of the gallium, indium, tin and magnesium powders is between 0.5 and 1 mm, and the d50 particle size of the titanium alloy powder is controlled between 0.5 and 2 mm, so that a metal substrate with a melting point temperature close to 110°C can be obtained.

[0039] Any of the aforementioned metal substrates can be introduced Figure 2In the 3D printing device shown, the substrate is stacked layer by layer to the corresponding position using its printing needle and cooled and solidified to achieve 3D printing.

[0040] During the printing process, the printing needle 3 can be flexibly moved to the top of the target printing position of the turntable 11 by the mechanical arm or gantry structure provided on the top of the sealed chamber 1, and the droplets fed by the temperature control pipeline system can be dropped to the target printing position; then, a dry air column with a temperature lower than room temperature is sprayed toward the printing position from different directions by synchronous control, and the alloy droplets are gradually cooled from the outside to the inside by the air column, and the air flow pressure is used to shape them during the cooling and shaping process.

[0041] The temperature control pipeline system that supplies the liquid metal substrate to the printing needle 3 can be arranged outside the sealed chamber 1 to regularly receive the uniformly melted metal substrate in the aforementioned oscillation container. For the metal substrate composed of gallium, indium, tin, blended powder and titanium alloy powder provided in the aforementioned embodiments, the present application can generally maintain the temperature control pipeline at a constant temperature of more than 150°C. The temperature control pipeline system preferably uses a copper inner wall, and the outside of the copper inner wall can be wrapped with a heat resistance wire isolated by sealing paint, and a heat insulation layer is further provided outside the heat resistance wire to keep the metal substrate in the tube at a suitable temperature state to ensure the fluidity of the metal substrate in the printing needle.

[0042] The cold air nozzle 2 for realizing the above-mentioned air cooling operation can be referred to Figure 2 In a manner, the cold air nozzles 2 are arranged in pairs in the sealed chamber 1 to spray cooling air columns toward the printing operation position on the turntable 11. The rear end of each cold air nozzle 2 is also connected to a condensation system, which is connected to each cold air nozzle 2 to cool down the air column sprayed by the cold air nozzle 2, thereby increasing the condensation speed of the metal substrate.

[0043] For target printing models with relatively complex internal structures, in order to avoid the already condensed and formed structures blocking the airflow and affecting the cooling of the target printing position, the turntable 11 in this application is generally set to be driven by a high-precision stepper motor to control its horizontal rotation angle, and driven by a hydraulic device to control its up and down lifting height. Therefore, the deflection angle between the target position of the printing operation and each nozzle on the side wall of the equipment can be adjusted by means of the lifting and rotation of the turntable 11, so that the airflow injection path avoids the metal model structure that has been condensed and fixed to form, and avoids the influence of the airflow on other printing structures. At the same time, such a design can further ensure that the airflow of each airflow nozzle can accurately reach the target printing position, so as to exert a force on the metal droplets so that the force is more balanced during the cooling and solidification process, thereby obtaining a better shaping effect.

[0044] In order to further improve the guiding property of the gas column during the condensation of the metal droplets, the present application preferably sets a Figure 3The airflow guide device 22 shown is used to limit the airflow from diverging outside the spraying direction, so as to prevent the airflow from diverging and affecting the effect of the metal droplets on the target printing position. As a result, the cooling airflows in different directions can be more accurately sprayed in pairs from two opposite directions to the metal droplets at the same time, acting on the droplets together, using the jet airflow on one side of the droplet to provide support, and using the jet airflow on the other side of the droplet to apply pressure, so that the surface of the droplet is applied by the air column during the cooling process to make it more uniform and flat. Figure 2 In the cubic sealed cavity 1 shown, the present application preferably provides at least one set of cold air nozzles 2 with opposite airflow spraying directions on the front, back, left and right walls. Each pair of airflows with opposite spraying directions can provide support for both sides of the droplet at the same time, so as to achieve accurate shaping during the solidification process on the metal surface through airflow pressure.

[0045] Each cold air nozzle 2 can flexibly adjust its deflection direction relative to the side wall through its own deflection mechanism, thereby changing the airflow injection angle. Therefore, each air column can appropriately adjust the air column injection direction in accordance with the rotation angle and lifting height of the turntable 11, thereby avoiding the formed model structure and directly injecting the cooling air column to the target position, applying pressure to the metal droplets at the target printing position to achieve cooling and shaping.

[0046] During the spraying process, the cooling airflow sprayed by each nozzle is generally preferably passed through a condensation system in advance, and the condensation system reduces its temperature to below room temperature, so as to quickly reduce the surface temperature of the droplets, so that the surface of the droplets at the target printing position quickly hardens to form a force-bearing surface that can accurately receive the force of the air column. At this time, the high temperature remaining inside the droplets can keep the droplets in a non-condensed state that can be shaped for a certain period of time. In this state, the droplets can be flexibly adjusted by the spray air pressure applied to them in all directions, and the metal droplets can be shaped into a suitable form by pressurizing them to 1.2 to 2 times the ambient air pressure. After they are completely cooled and solidified, the detailed structure of the target model can be accurately expressed.

[0047] In a more preferred implementation, in order to further enhance the shaping effect of the above-mentioned oppositely-sprayed air columns on the metal droplets at the printing position, the present application may further add a booster system for the jet airflow in the 3D printing device. Thus, the airflow pressure for the air-cooling treatment of the metal droplets is increased by the booster system connected between the cold air nozzle 2 and the condensation system, so as to adapt to a longer injection stroke and improve the shaping effect of the metal droplets solidified and hardened by the component. Specifically, the booster system can pressurize the airflow through a gas booster device when the target printing position is far from the nozzle to ensure that it exerts a force on the surface of the metal droplet when it reaches the target position. It can also adjust the stress by flexibly controlling the airflow pressure when it is necessary to apply additional force to the droplet surface to form special effects such as concave structures. In this process, the airflows on both sides of the droplet can also cooperate with each other through the control algorithm inside the device, using the air column on one side to provide support for the droplet, and using the air column on the other side to achieve the surface processing requirements.

[0048] Therefore, the above-mentioned 3D printing device can decompose the target model layer by layer according to the target model, so as to stack the layers obtained by the decomposition layer by layer, and form the target structure layer by layer by shaping and solidifying the metal droplets. In this process, the turntable 11 can be flexibly controlled to rotate or lift to a suitable height to receive the metal droplets and provide a suitable air column injection path and air pressure action angle for them. After the metal droplets are injected into the target working position by the printing needle, the printing device can spray cooling air columns from all directions of the sealed cavity 1 according to the shaping requirements, so as to cause the metal droplets to cool and form according to their target structure. Repeating the above process layer by layer, the target model can be gradually restored to the turntable 11.

[0049] In the above process, since each layer of metal droplets needs to be stably connected to each other, it is also necessary to consider optimizing the strength of the connection structure between each droplet. Since the metal droplets at each printing position need to be connected to the already formed structure at its bottom and side, the present application generally also needs to spray medium powder to the connection position of the metal droplets in real time during the aforementioned operation process, so as to promote reliable connection between the two structures through the material properties of the medium powder. For the liquid alloy droplets containing Ga, In, Sn, Zn, Cd, Mg and other elements provided by the present application, on the one hand, the powder particles formed by grinding ink after the alloy condenses and solidifies can be used as an intermediate medium, and the powder particles sprinkled on the surface of the liquid metal can be used to continuously induce flow and deformation after being wetted, and the droplet flow is driven by the uneven gradient of the droplet surface tension, so as to realize the coupling between the metal particles and the liquid metal, so that the metal droplets can be more closely adhered to the solidified metal.

[0050] In addition, based on the liquid metal endocytosis effect, the present application can also introduce charge imbalance by spraying mixed powder particles of titanium alloy powder and carbon and / or manganese, thereby obtaining an enhanced effect of thermal conductivity at the connection position. By incorporating the above-mentioned particles, the adhesion of the liquid metal substrate to the hard surface of the existing molding structure is significantly improved, and the plasticity of the material itself is improved. The improvement in thermal conductivity can also cause the micro-surface of the molding structure to tend to melt or at least partially soften, thereby promoting its fusion with the newly added metal droplets, making the connection between the two tighter and more reliable.

[0051] The above-mentioned various powder particles can be Figure 2 The medium powder spraying port 12 shown in the middle surrounds the outer side of the turntable, and uses the upward airflow provided by the spraying port to disperse various types of powders into the space where the printing area is located. At this time, the dripping metal droplets can absorb powder particles during their movement path; on the other hand, when the cold air nozzle sprays the cooling air column, the air column can pass through the medium powder spraying port 12 and carry the powder upward, and further cool the temperature of the droplets while spraying the medium powder to the working position, thereby providing medium particles for the connection position between adjacent droplets, so that different droplet structures can be fully and tightly connected.

[0052] In order to ensure the spray direction of the cooling air column in the above process and avoid the influence of air flow divergence on the shaping of the surface structure of the metal droplets in the spray path, the present application can further embed a cooling air nozzle at the end of each cooling air nozzle 2. Figure 3 The airflow guide device 22 shown. The airflow guide device 22 can rotate synchronously along the inner wall of the cold air nozzle 2 during the airflow injection process, and use the airflow guide at the center position of the airflow to compress the radius of the airflow passing surface, thereby compressing the airflow while correcting the cyclone direction through the guide device, thereby limiting the divergence phenomenon during the airflow injection process.

[0053] See Figure 3 As shown, the airflow guide device 22 can be specifically configured to be composed of two guide flaps 223 arranged opposite to each other. The two guide flaps can be fixed by welding with ribs, and the two guide flaps need to be staggered at a certain angle at the center of the cooling nozzle to form an airflow guide channel; The two guide flaps 223 can be provided with a limit strip 24 folded outward and protruding from the surface of the guide flap at their bottom edges. The inner wall of the nozzle can cooperate with the limit strip, and an annular rotation guide groove 21 can be provided along the circumference of the inner wall. Thus, the airflow guide device 22 can be embedded in the inner wall of the nozzle through the limit strip 24 to realize rotation along the circumference of the inner wall and keep rotating along the inner wall of the nozzle.

[0054] During the airflow, since the guide flaps 223 are separated far apart at the bottom and gathered inward at the top, the concave curvature thereof can form an airflow guide channel along the center of the nozzle during the rotation of each guide flap 223, providing a certain boosting effect. In addition, the concave curvature of the guide flap can also form a vortex cyclone outside the airflow guide channel during the airflow injection process, thereby further limiting the outward divergence of the airflow during the injection process through the inward cyclone, further providing a certain gathering and guiding effect for the injection airflow. At the same time, the vortex cyclone can also carry more particles when passing through the medium powder dispersion area and apply them to the working surface to improve the tightness of the connection structure between the droplets.

[0055] The above is only an implementation method of the present application, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present application. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application.

Claims

1. A low melting point liquid alloy suitable for 3D printing, characterized in that: The liquid alloy is prepared according to the following steps: Step 1, heating gallium, indium, tin, blended powder and titanium alloy powder in a mass ratio of 27.2-38.3:4.8-8.8:3.5-5.8:3.7-8.8:43-60 under vacuum or protective atmosphere until completely melted; Step 2, the melted mixture is shaken until the melt sample is uniform, and then injected into the substrate pipeline of the 3D printer, so that the 3D printer can inject the substrate in the pipeline into the corresponding printing position according to the printing model requirements under a constant temperature of more than 150° C., thereby cooling layer by layer to obtain the target model; Wherein, the prepared powder is magnesium powder or a mixture of magnesium powder and any one of the following metal powders: zinc or cadmium; The titanium alloy powder includes titanium powder accounting for more than 90% by mass.

2. The low melting point liquid alloy suitable for 3D printing according to claim 1, characterized in that: The titanium alloy powder also includes: titanium chloride and / or titanium diboride powder.

3. The low melting point liquid alloy suitable for 3D printing according to claim 1, characterized in that: The mixed powder includes magnesium powder and zinc powder in a mass ratio of 1:1 to 3.

4. The low melting point liquid alloy suitable for 3D printing according to claim 1, characterized in that: The mixed powder includes magnesium powder and cadmium powder in a mass ratio of 1:1-3.

5. The low melting point liquid alloy suitable for 3D printing as described in claims 1-4, characterized in that: The gallium, indium, tin and mixed powders have a particle size range of 0.5 to 1 mm; The d50 particle size of titanium alloy powder is between 0.5 and 2 mm.

6. The low melting point liquid alloy suitable for 3D printing as described in claims 1-5, characterized in that: The liquid alloy consists of gallium, indium, tin, magnesium, zinc, titanium, titanium chloride and titanium diboride, and the mass ratio thereof is 35.3:8.3:5.2:3:3:56:1:

1.

7. The low melting point liquid alloy suitable for 3D printing according to claim 6, characterized in that: The 3D printer injects the base material in the copper inner wall pipeline into the printing pin of the printer according to the requirements of the printing model under a constant temperature of 160-180°C.

8. A 3D printing shaping method for a low melting point liquid alloy suitable for 3D printing, characterized in that: For the liquid alloy according to claims 1-7, the steps include: When the liquid alloy is injected into the corresponding printing position through the printing needle, a dry gas column with a temperature lower than room temperature is simultaneously sprayed toward the printing position from different directions. The gas column cools the alloy droplets from the outside and shapes them using the air flow pressure during the cooling and shaping process.

9. The 3D printing shaping method of a low melting point liquid alloy suitable for 3D printing according to claim 8, characterized in that: Before the liquid alloy is injected into the printing needle, the temperature of the liquid alloy in the pipeline is controlled at a constant temperature above 150°C.

10. The 3D printing shaping method of low melting point liquid alloy suitable for 3D printing as described in claims 8-9, characterized in that: The air column is also pre-pressurized to a pressure of 1.2 to 2 times the ambient pressure. During the air column injection process, medium powder is also blown to the printing position. The medium powder is powder particles formed by crushing liquid alloy after solidification, or the medium powder is a mixed powder particle of titanium alloy powder and carbon and / or manganese.

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