3D printing continuous carbon fiber reinforced thermoplastic composite material and preparation method thereof

Abstract

The invention discloses a 3D printing continuous carbon fiber reinforced thermoplastic composite material and a preparation method thereof.The 3D printing continuous carbon fiber reinforced thermoplastic composite material comprises a continuous carbon fiber reinforced nylon layer and a chopped carbon fiber reinforced nylon layer, and the continuous carbon fiber reinforced nylon layer comprises a plurality of continuous carbon fiber reinforced nylon sub-layers arranged in the first direction; the extension directions of the continuous carbon fibers in the same continuous carbon fiber reinforced nylon sub-layer are the same, the extension directions of the continuous carbon fibers in the two adjacent continuous carbon fiber reinforced nylon sub-layers are different, the first direction is the thickness direction of the continuous carbon fiber reinforced nylon sub-layer, the number of the short carbon fiber reinforced nylon layers is two, and the second direction is the thickness direction of the short carbon fiber reinforced nylon sub-layer. The two chopped carbon fiber reinforced nylon layers are arranged on the two opposite sides of the continuous carbon fiber reinforced nylon layer in the first direction. According to the 3D printing continuous carbon fiber reinforced thermoplastic composite material disclosed by the invention, the microcrack resistance of the 3D printing continuous carbon fiber reinforced thermoplastic composite material can be effectively enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials and liquid hydrogen storage and transportation, and particularly relates to a 3D printing continuous carbon fiber reinforced thermoplastic composite material and a preparation method thereof. BACKGROUND

[0002] At present, with the wide application of hydrogen energy in the fields of aerospace and energy storage equipment, a light-weight, high-strength and ultra-low-temperature-resistant hydrogen storage container becomes a key equipment. Carbon fiber reinforced composite materials become an important material for manufacturing liquid hydrogen storage tanks due to high specific strength, high specific modulus and excellent corrosion resistance. However, the traditional thermosetting resin-based composite materials are prone to interlaminar microcracks in an ultra-low-temperature environment (such as an ultra-low-temperature environment of-253 DEG C), which reduces the gas tightness of the storage tank and causes a safety hazard.

[0003] Thermoplastic-based composite materials gradually become a candidate system for a new generation of liquid hydrogen storage tank composite materials due to their high toughness, recyclability and hot weldability. The 3D printing (fused deposition modeling) technology can quickly realize the molding of composite parts with complex structures, and has the advantages of high design freedom and high manufacturing efficiency. However, the existing 3D printing thermoplastic carbon fiber composite materials are prone to generate many pores and thermal residual stress in the forming process, which results in insufficient microcrack resistance in the ultra-low-temperature environment, and seriously restricts the popularization and application of the materials in high-demand application scenarios such as liquid hydrogen storage tanks. Therefore, how to enhance the microcrack resistance of the 3D printing thermoplastic carbon fiber composite material has become a technical problem to be solved. SUMMARY

[0004] The present application aims to at least solve one of the technical problems in the prior art. To this end, one object of the present application is to provide a 3D printing continuous carbon fiber reinforced thermoplastic composite material, which can effectively enhance the microcrack resistance of the 3D printing continuous carbon fiber reinforced thermoplastic composite material.

[0005] The present application also provides a preparation method of the 3D printing continuous carbon fiber reinforced thermoplastic composite material.

[0006] The 3D printing continuous carbon fiber reinforced thermoplastic composite material according to the first aspect of the present application comprises: a continuous carbon fiber reinforced nylon layer, the continuous carbon fiber reinforced nylon layer comprises a plurality of sub-continuous carbon fiber reinforced nylon layers arranged along a first direction, the continuous carbon fibers in the same sub-continuous carbon fiber reinforced nylon layer have the same extension direction, the continuous carbon fibers in the adjacent two sub-continuous carbon fiber reinforced nylon layers have different extension directions, and the first direction is the thickness direction of the continuous carbon fiber reinforced nylon layer; and a chopped carbon fiber reinforced nylon layer, the chopped carbon fiber reinforced nylon layer comprises two layers, the two layers of the chopped carbon fiber reinforced nylon layer are arranged on the opposite sides of the continuous carbon fiber reinforced nylon layer along the first direction, the chopped carbon fiber reinforced nylon layer comprises at least one layer of chopped carbon fibers, and the chopped carbon fibers in the chopped carbon fiber reinforced nylon layer have the same extension direction.

[0007] The 3D printing continuous carbon fiber reinforced thermoplastic composite material according to the first aspect of the present application comprises: a continuous carbon fiber reinforced nylon layer, the continuous carbon fiber reinforced nylon layer comprises a plurality of sub-continuous carbon fiber reinforced nylon layers arranged along a first direction, the continuous carbon fibers in the same sub-continuous carbon fiber reinforced nylon layer have the same extension direction, the continuous carbon fibers in the adjacent two sub-continuous carbon fiber reinforced nylon layers have different extension directions, and the first direction is the thickness direction of the continuous carbon fiber reinforced nylon layer; and a chopped carbon fiber reinforced nylon layer, the chopped carbon fiber reinforced nylon layer comprises two layers, the two layers of the chopped carbon fiber reinforced nylon layer are arranged on the opposite sides of the continuous carbon fiber reinforced nylon layer along the first direction, the chopped carbon fiber reinforced nylon layer comprises at least one layer of chopped carbon fibers, and the chopped carbon fibers in the chopped carbon fiber reinforced nylon layer have the same extension direction.

[0008] According to some embodiments of the present application, the included angle between the continuous carbon fibers in the adjacent two sub-continuous carbon fiber reinforced nylon layers ranges from 45° to 90°; and / or, the continuous carbon fiber reinforced nylon layer comprises three sub-continuous carbon fiber reinforced nylon layers arranged along the first direction.

[0009] According to some embodiments of the present application, one of the two sub-continuous carbon fiber reinforced nylon layers comprises six continuous carbon fibers, and the other of the two sub-continuous carbon fiber reinforced nylon layers comprises twelve continuous carbon fibers.

[0010] According to some embodiments of the present application, the continuous carbon fiber reinforced nylon layer comprises continuous carbon fiber reinforced polyamide 6-I; and / or, the chopped carbon fiber reinforced nylon layer comprises chopped carbon fiber reinforced polyamide 6.

[0011] According to some embodiments of the present application, the porosity of the 3D printing continuous carbon fiber reinforced thermoplastic composite material is less than 1%.

[0012] According to some embodiments of the present application, the 3D printed continuous carbon fiber reinforced thermoplastic composite material has a micro-crack initiation strain range of 0.4% to 0.6% in an environment of -196°C.

[0013] The method for preparing the 3D printed continuous carbon fiber reinforced thermoplastic composite material according to the second aspect of the present application, the 3D printed continuous carbon fiber reinforced thermoplastic composite material is the 3D printed continuous carbon fiber reinforced thermoplastic composite material according to the first aspect of the present application, the method comprises the following steps:

[0014] Preparation of the continuous carbon fiber and the chopped carbon fiber;

[0015] The continuous carbon fiber and the chopped fiber are put into a printing device, and the sub-continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer are printed by a fused deposition modeling 3D printing process;

[0016] The prepared sub-continuous carbon fiber reinforced nylon layer is stacked in a predetermined direction to obtain the continuous carbon fiber reinforced nylon layer, and the prepared chopped carbon fiber reinforced nylon layer is laid on the opposite sides of the continuous carbon fiber reinforced nylon layer along the first direction;

[0017] The continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer are placed in an argon atmosphere, an atmospheric pressure of 1-2 bar, and an environment with a temperature of 160-210°C, and are heat treated for 60-120 min, and are cooled to room temperature at a cooling rate of 10°C / min to obtain the 3D printed continuous carbon fiber reinforced thermoplastic composite material.

[0018] The method for preparing the 3D printed continuous carbon fiber reinforced thermoplastic composite material according to the embodiments of the present application, the chopped carbon fiber reinforced nylon layer is arranged on the opposite sides of the continuous carbon fiber reinforced nylon layer along the first direction, and the continuous carbon fiber reinforced nylon layer comprises a plurality of sub-continuous carbon fiber reinforced nylon layers arranged along the first direction, the continuous carbon fibers in the same sub-continuous carbon fiber reinforced nylon layer have the same extension direction, and the continuous carbon fibers in the adjacent two sub-continuous carbon fiber reinforced nylon layers have different extension directions, so that the continuous carbon fibers in the adjacent sub-continuous carbon fiber reinforced nylon layers inside the continuous carbon fiber reinforced nylon layer form a cross structure, and the chopped carbon fiber reinforced nylon layer arranged on the outside of the continuous carbon fiber reinforced nylon layer can effectively enhance the micro-crack resistance of the 3D printed continuous carbon fiber reinforced thermoplastic composite material.

[0019] According to some embodiments of the present application, before the continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer are heat treated, a vacuum bag is sleeved outside the continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer;

[0020] After the heat treatment of the continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer is completed, the vacuum bag is removed from the outside of the continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer, and the 3D printed continuous carbon fiber reinforced thermoplastic composite material is prepared.

[0021] According to some embodiments of the present application, the thickness dimension of the continuous carbon fiber in the first direction is 0.125 mm, and the printing filling density is 100%; and / or, the thickness dimension of the chopped carbon fiber in the first direction is 0.125 mm, and the printing filling density is 100%.

[0022] According to some embodiments of the present application, the printing device comprises a continuous fiber nozzle and a chopped fiber nozzle, the continuous fiber nozzle is used to spray the continuous carbon fiber, and the chopped fiber nozzle is used to spray the chopped carbon fiber; wherein, the working temperature range of the continuous fiber nozzle is 242℃-262℃; and / or, the working temperature range of the chopped fiber nozzle is 260℃-280℃.

[0023] Additional aspects and advantages of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0024] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description of embodiments, taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1 is a simplified schematic diagram of a 3D printed continuous carbon fiber reinforced thermoplastic composite material according to some embodiments of the present application;

[0026] Figure 2 is Figure 1 is a simplified schematic diagram of a continuous carbon fiber reinforced nylon layer and a chopped carbon fiber reinforced nylon layer in a 3D printed continuous carbon fiber reinforced thermoplastic composite material in

[0027] Figure 3 is Figure 1 is a schematic diagram of a three-point bending test of a 3D printed continuous carbon fiber reinforced thermoplastic composite material in

[0028] REFERENCE SIGNS:

[0029] 100. 3D printed continuous carbon fiber reinforced thermoplastic composite material;

[0030] 11. Continuous carbon fiber reinforced nylon layer; 12. Chopped carbon fiber reinforced nylon layer;

[0031] 21. Vacuum bag; 211. First breather membrane; 212. Second breather membrane; 23. Polytetrafluoroethylene film; 24. Sealing tape; 25. Stainless steel plate. DETAILED DESCRIPTION

[0032] Embodiments of the present application are described in detail below with reference to several examples illustrated in the attached drawings, wherein like or similar elements are denoted by the same or similar reference signs throughout the drawings. The embodiments described below are exemplary only, and are not to be construed as limiting the present application.

[0033] Reference is made below to Figures 1-3 A 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 according to an embodiment of the present application is described below.

[0034] Reference is made to Figures 1-3 The 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 according to the first aspect embodiment of the present application comprises a continuous carbon fiber reinforced nylon layer 11 and a chopped carbon fiber reinforced nylon layer 12. The continuous carbon fiber reinforced nylon layer 11 comprises a plurality of sub-continuous carbon fiber reinforced nylon layers 11 arranged along a first direction (e.g. e1 direction in the attached drawings). The continuous carbon fibers in the same sub-continuous carbon fiber reinforced nylon layer 11 have the same extension direction, and the continuous carbon fibers in adjacent two sub-continuous carbon fiber reinforced nylon layers 11 have different extension directions. The first direction is the thickness direction of the continuous carbon fiber reinforced nylon layer 11. The chopped carbon fiber reinforced nylon layer 12 comprises two layers. The two layers of the chopped carbon fiber reinforced nylon layer 12 are arranged on opposite sides of the continuous carbon fiber reinforced nylon layer 11 along the first direction. The chopped carbon fiber reinforced nylon layer 12 comprises at least one layer of chopped carbon fibers. The chopped carbon fibers in the chopped carbon fiber reinforced nylon layer 12 have the same extension direction.

[0035] The short carbon fiber reinforced nylon layer 12 includes two layers, and the two layers of short carbon fiber reinforced nylon layer 12 are arranged on opposite sides of the continuous carbon fiber reinforced nylon layer 11 along the first direction, so that the short carbon fiber reinforced nylon layer 12 is located on the outside of the continuous carbon fiber reinforced nylon layer 11. The short carbon fiber reinforced nylon layer 12 arranged on the outside can enhance the hardness of the surface of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100, and enhance the crack resistance of the surface of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100. For example, the short carbon fiber reinforced nylon layer 12 arranged on the outside can form a dispersion distribution of the reinforcing network on the surface of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100. When the stress is concentrated on the surface of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100, the short carbon fiber reinforced nylon layer 12 can timely disperse the stress, and reduce or avoid the generation and expansion of cracks.

[0036] In addition, the continuous carbon fiber reinforced nylon layer 11 includes a plurality of sub-continuous carbon fiber reinforced nylon layers 11 arranged along the first direction. The extension directions of the continuous carbon fibers in the same sub-continuous carbon fiber reinforced nylon layer 11 are the same. The extension directions of the continuous carbon fibers in adjacent two sub-continuous carbon fiber reinforced nylon layers 11 are different. The extension directions of the continuous carbon fibers in adjacent sub-continuous carbon fiber reinforced nylon layers 11 are different. The continuous carbon fibers in adjacent sub-continuous carbon fiber reinforced nylon layers 11 can form a cross structure, which can enhance the micro-crack resistance of the continuous carbon fiber reinforced nylon layer 11. For example, in an ultra-low temperature environment of -196°C, the expansion path of the micro-crack will be deflected by the continuous carbon fibers with different directions. Since each deflection will consume the fracture energy of the crack, the expansion speed of the micro-crack in the continuous carbon fiber reinforced nylon layer 11 can be slowed down, thereby reducing the possibility of generating micro-cracks in the continuous carbon fiber reinforced nylon layer 11.

[0037] For example, the short carbon fiber reinforced nylon layer 12 can include one layer of short carbon fiber, two layers of short carbon fiber, three layers of short carbon fiber, or four layers of short carbon fiber. The short carbon fiber reinforced nylon layer 12 includes at least one layer of short carbon fiber, and the extension directions of the short carbon fibers in the short carbon fiber reinforced nylon layer 12 are the same. In this way, the structural strength of the short carbon fiber reinforced nylon layer 12 can be enhanced, thereby enhancing the crack resistance of the short carbon fiber reinforced nylon layer 12.

[0038] According to the 3D printing continuous carbon fiber reinforced thermoplastic composite material 100 of the embodiment of the present application, the chopped carbon fiber reinforced nylon layer 12 is arranged on the opposite sides of the continuous carbon fiber reinforced nylon layer 11 along the first direction, and the continuous carbon fiber reinforced nylon layer 11 includes a plurality of sub-continuous carbon fiber reinforced nylon layers 11 arranged along the first direction, the extension directions of the continuous carbon fibers in the same sub-continuous carbon fiber reinforced nylon layer 11 are the same, and the extension directions of the continuous carbon fibers in the adjacent two sub-continuous carbon fiber reinforced nylon layers 11 are different, so that the continuous carbon fibers in the adjacent sub-continuous carbon fiber reinforced nylon layers 11 inside the continuous carbon fiber reinforced nylon layer 11 form a cross structure, and the chopped carbon fiber reinforced nylon layer 12 is arranged on the outside of the continuous carbon fiber reinforced nylon layer 11, which can effectively enhance the micro-crack resistance of the 3D printing continuous carbon fiber reinforced thermoplastic composite material 100.

[0039] With reference to Figures 1-3 According to some embodiments of the present application, the included angle of the continuous carbon fibers in the adjacent two sub-continuous carbon fiber reinforced nylon layers 11 ranges from 45° to 90°. For example, the included angle of the continuous carbon fibers in the adjacent two sub-continuous carbon fiber reinforced nylon layers 11 can be 45°, 55°, 70°, 80°, 90°, etc. By setting the included angle of the continuous carbon fibers in the adjacent two sub-continuous carbon fiber reinforced nylon layers 11 to range from 45° to 90°, the micro-crack resistance of the continuous carbon fiber reinforced nylon layer 11 can be effectively improved, and the propagation path of the micro-crack can be deflected by the continuous carbon fibers with different orientations, which can slow down the propagation speed of the micro-crack, thereby reducing the possibility of generating micro-cracks, and the possibility of failure of the continuous carbon fiber reinforced nylon layer 11 due to the too large included angle of the continuous carbon fibers in the adjacent two sub-continuous carbon fiber reinforced nylon layers 11 can be avoided.

[0040] With reference to Figures 1-3 According to some embodiments of the present application, the continuous carbon fiber reinforced nylon layer 11 includes three sub-continuous carbon fiber reinforced nylon layers 11 arranged along the first direction. The thickness of the continuous carbon fiber reinforced nylon layer 11 along the first direction can be small, which can enhance the micro-crack resistance of the whole continuous carbon fiber reinforced nylon layer 11.

[0041] With reference to Figures 1-3According to some embodiments of the present application, one of the two sub-continuous carbon fiber reinforced nylon layers 11 comprises six continuous carbon fibers, and the other of the two sub-continuous carbon fiber reinforced nylon layers 11 comprises twelve continuous carbon fibers. The sub-continuous carbon fiber reinforced nylon layer 11 comprising twelve continuous carbon fibers can be used as a main load-bearing layer of the continuous carbon fiber reinforced nylon layer 11, which bears the main tensile force, compression force and other stresses. The sub-continuous carbon fiber reinforced nylon layer 11 comprising six continuous carbon fibers can be used as an auxiliary layer of the continuous carbon fiber reinforced nylon layer 11, which disperses the stresses transmitted by the main load-bearing layer. The modulus gradient of the two sub-continuous carbon fiber reinforced nylon layers 11 can be different due to the different number of continuous carbon fiber reinforced nylon layers 11 contained in the two sub-continuous carbon fiber reinforced nylon layers 11. This can effectively reduce the possibility of stress convexity between the two adjacent sub-continuous carbon fiber reinforced nylon layers 11, thereby effectively reducing the generation of interlayer microcracks and further reducing the possibility of microcracks in the continuous carbon fiber reinforced nylon layer 11.

[0042] For example, the three sub-continuous carbon fiber reinforced nylon layers 11 are a first sub-continuous carbon fiber reinforced nylon layer 11 and two second sub-continuous carbon fiber reinforced nylon layers 11. The two second sub-continuous carbon fiber reinforced nylon layers 11 are respectively located on the opposite sides of the first sub-continuous carbon fiber reinforced nylon layer 11 along the first direction. The first sub-continuous carbon fiber reinforced nylon layer 11 comprises twelve continuous carbon fibers, the extension direction of each layer of continuous carbon fibers in the first sub-continuous carbon fiber reinforced nylon layer 11 is the same, the second sub-continuous carbon fiber reinforced nylon layer 11 comprises six continuous carbon fibers, the extension direction of each layer of continuous carbon fibers in the second sub-continuous carbon fiber reinforced nylon layer 11 is the same, and the angle between the continuous carbon fibers in the second sub-continuous carbon fiber reinforced nylon layer 11 and the continuous carbon fibers in the first sub-continuous carbon fiber reinforced nylon layer 11 is 90°. The continuous carbon fibers in the second sub-continuous carbon fiber reinforced nylon layer 11 and the continuous carbon fibers in the first sub-continuous carbon fiber reinforced nylon layer 11 can form a cross structure, which can effectively enhance the microcrack resistance of the continuous carbon fiber reinforced nylon layer 11, thereby reducing the possibility of microcracks in the continuous carbon fiber reinforced nylon layer 11.

[0043] Referring to Figures 1-3 According to some embodiments of the present application, the continuous carbon fiber reinforced nylon layer 11 comprises continuous carbon fiber reinforced polyamide 6-I, so that the continuous carbon fiber reinforced nylon layer 11 has better tensile resistance and stronger hardness.

[0044] Referring to Figures 1-3 According to some embodiments of the present application, the chopped carbon fiber reinforced nylon layer 12 comprises chopped carbon fiber reinforced polyamide 6, so that the chopped carbon fiber reinforced nylon layer 12 has better crack resistance and stronger hardness.

[0045] Referring to Figures 1-3 According to some embodiments of the present application, the porosity of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 is less than 1%, which can ensure that the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 has strong micro-crack resistance, effectively reducing the possibility of micro-crack of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100, especially in the environment of ultra-low temperature (for example, -196℃).

[0046] For example, the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 is used for a liquid hydrogen storage tank, and the temperature of the liquid hydrogen is ultra-low temperature (for example, -196℃). By the porosity of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 being less than 1%, the micro-crack resistance of the storage tank in the ultra-low temperature environment can be effectively improved, the possibility of micro-crack of the storage tank can be reduced, and the air tightness of the storage tank can be improved. Accordingly, when the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 is used for other ultra-low temperature lightweight composite structural parts, the micro-crack resistance of the other ultra-low temperature lightweight composite structural parts can also be effectively improved.

[0047] Referring to Figures 1-3 According to some embodiments of the present application, the micro-crack initiation strain range of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 in the environment of -196℃ is 0.4% to 0.6%. For example, the micro-crack initiation strain of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 in the environment of -196℃ is 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, etc. By the micro-crack initiation strain range of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 in the environment of -196℃ being 0.4% to 0.6%, the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 can have strong micro-crack resistance, effectively reducing the possibility of micro-crack of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100, especially in the environment of ultra-low temperature (for example, -196℃).

[0048] Referring to Figures 1-3 According to the preparation method of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 according to the second aspect of the present application, the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 is the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 according to the first aspect of the present application, and the preparation method comprises the following steps:

[0049] Preparation of continuous carbon fibers and chopped carbon fibers;

[0050] The continuous carbon fiber and the chopped fiber are placed into a printing device, and the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 are printed by a fused deposition modeling 3D printing process;

[0051] The prepared continuous carbon fiber reinforced nylon layer 11 is stacked in a preset direction to obtain the continuous carbon fiber reinforced nylon layer 11, and the prepared chopped carbon fiber reinforced nylon layer 12 is laid on the opposite sides of the continuous carbon fiber reinforced nylon layer 11 along the first direction;

[0052] The continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 are placed in an argon atmosphere, an atmospheric pressure of 1-2 bar, and a temperature of 160-210°C, and are heat treated for 60-120 min, and are cooled to room temperature at a cooling rate of 10°C / min to obtain the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100. The heat treatment process effectively reduces the porosity of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 generated in the printing process, improves the interlayer bonding strength of the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12, and ensures the structural integrity of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 in an extremely low temperature environment.

[0053] In addition, the preparation process of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 is relatively simple and has low preparation difficulty. When the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 is suitable for liquid hydrogen storage tanks and other ultralow-temperature lightweight composite structural parts, the industrial production of the liquid hydrogen storage tanks and other ultralow-temperature lightweight composite structural parts can be facilitated.

[0054] It should be explained that the stacking of the prepared continuous carbon fiber reinforced nylon layer 11 in a preset direction means that the continuous carbon fiber reinforced nylon layer 11 includes a plurality of continuous carbon fiber reinforced nylon layers 11 arranged along the first direction, and the included angle of the continuous carbon fibers in the adjacent two continuous carbon fiber reinforced nylon layers 11 ranges from 45° to 90°.

[0055] According to the method for manufacturing the 3D printing continuous carbon fiber reinforced thermoplastic composite material 100, the chopped carbon fiber reinforced nylon layer 12 is arranged on the opposite sides of the continuous carbon fiber reinforced nylon layer 11 along the first direction, and the continuous carbon fiber reinforced nylon layer 11 includes a plurality of sub-continuous carbon fiber reinforced nylon layers 11 arranged along the first direction, the continuous carbon fibers in the same sub-continuous carbon fiber reinforced nylon layer 11 have the same extension direction, and the continuous carbon fibers in the adjacent two sub-continuous carbon fiber reinforced nylon layers 11 have different extension directions, so that the continuous carbon fibers in the adjacent sub-continuous carbon fiber reinforced nylon layers 11 inside the continuous carbon fiber reinforced nylon layer 11 form a cross structure, and the chopped carbon fiber reinforced nylon layer 12 is arranged outside the continuous carbon fiber reinforced nylon layer 11, which can effectively enhance the micro-crack resistance of the 3D printing continuous carbon fiber reinforced thermoplastic composite material 100.

[0056] With reference to Figures 1-3 According to some embodiments of the present application, before the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 are heat treated, a vacuum bag 21 is sleeved outside the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12;

[0057] For example, the vacuum bag 21 is sleeved outside the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12, including:

[0058] The polytetrafluoroethylene film 23 is arranged on the opposite sides of the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 along the first direction, which can avoid that the fine particles of the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 adhere to the surface of the vacuum bag 21;

[0059] The side of the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 provided with the polytetrafluoroethylene film 23 along the first direction is placed on the stainless steel plate 25, and the polytetrafluoroethylene film 23 can prevent fine particles of the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 from adhering to the surface of the stainless steel plate 25. The vacuum bag 21 is arranged on the side of the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 provided with the polytetrafluoroethylene film 23 along the first direction away from the stainless steel plate 25. The vacuum bag 21 includes a first breathing film 211 and a second breathing film 212. The first breathing film 211 is connected to the second breathing film 212. The first breathing film 211 extends along a second direction (for example, the e2 direction in the drawing). At least part of the second breathing film 212 extends obliquely along the first direction. The second breathing film 212 includes two. The two second breathing films 212 are respectively located at opposite ends of the first breathing film 211 along the second direction. One end of the second breathing film 212 is connected to the first breathing film 211, and the other end is connected to the stainless steel plate 25. After the vacuum bag 21 is evacuated, the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 are in a vacuum environment.

[0060] In addition, a sealing tape 24 is arranged between the second breathing film 212 and the stainless steel plate 25, which can further enhance the sealing effect between the second breathing film 212 and the stainless steel plate 25, so as to ensure that the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 are in a vacuum environment after the vacuum bag 21 is evacuated.

[0061] After the heat treatment of the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 is completed, the vacuum bag 21 is removed from the outside of the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12, and a 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 is prepared.

[0062] Before the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 are heat treated, the vacuum bag 21 is arranged outside the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12. The vacuum bag 21 can make the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 as a whole in a vacuum environment. The vacuum bag 21 can make the pressure uniformly distributed to the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12. While the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 are closely attached, the uniformly distributed pressure is conducive to reducing the porosity of the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12, thereby being conducive to improving the micro-crack resistance of the prepared 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 and reducing the porosity of the prepared 3D printed continuous carbon fiber reinforced thermoplastic composite material 100.

[0063] With reference to Figures 1-3 , according to some embodiments of the present application, the thickness dimension of the continuous carbon fiber in the first direction is 0.125 mm, and the printing filling density is 100%, so that the thickness of the continuous carbon fiber in the first direction is small, which can make the extrusion force distribution of the single layer of continuous carbon fiber more uniform, so that the single layer of continuous carbon fiber is more tightly stacked. By setting the printing filling density to 100%, the internal gap of the single layer of continuous carbon fiber can be made as small as possible, and thus the porosity of the continuous carbon fiber reinforced nylon layer 11 can be reduced, and the micro-crack resistance of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 can be improved.

[0064] With reference to Figures 1-3 , according to some embodiments of the present application, the thickness dimension of the chopped carbon fiber in the first direction is 0.125 mm, and the printing filling density is 100%, so that the thickness of the chopped carbon fiber in the first direction is small, which can make the extrusion force distribution of the single layer of chopped carbon fiber more uniform, so that the single layer of chopped carbon fiber is more tightly stacked. By setting the printing filling density to 100%, the internal gap of the single layer of chopped carbon fiber can be made as small as possible, and thus the porosity of the chopped carbon fiber reinforced nylon layer 12 can be reduced, and the micro-crack resistance of the 3D printed chopped carbon fiber reinforced thermoplastic composite material can be improved.

[0065] With reference to Figures 1-3 , according to some embodiments of the present application, the printing device comprises a continuous fiber nozzle and a chopped fiber nozzle, the continuous fiber nozzle is used to spray continuous carbon fiber, and the chopped fiber nozzle is used to spray chopped carbon fiber; wherein the working temperature range of the continuous fiber nozzle is 242℃-262℃, so that the continuous carbon fiber sprayed by the continuous fiber nozzle is in a molten state, and the molten accumulation forming of the continuous carbon fiber reinforced nylon layer 11 can be realized.

[0066] The working temperature range of the chopped fiber nozzle is 260℃-280℃, so that the chopped carbon fiber sprayed by the chopped fiber nozzle is in a molten state, and the molten accumulation forming of the chopped carbon fiber reinforced nylon layer 12 can be realized.

[0067] The preparation process of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 according to some embodiments of the present application is described below with reference to Figures 1-3 .

[0068] In this embodiment, the preparation steps of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 are as follows:

[0069] S1, preparing continuous carbon fiber and chopped carbon fiber;

[0070] S2, put the continuous carbon fiber and the chopped fiber into a printing device, print the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 by a fused deposition modeling 3D printing process;

[0071] S3, stack the prepared continuous carbon fiber reinforced nylon layer 11 in a preset direction to prepare the continuous carbon fiber reinforced nylon layer 11, and lay the prepared chopped carbon fiber reinforced nylon layer 12 on the opposite sides of the continuous carbon fiber reinforced nylon layer 11 along the first direction;

[0072] S4, place the continuous carbon fiber reinforced nylon layer 11 and the chopped carbon fiber reinforced nylon layer 12 in an argon atmosphere, atmospheric pressure 2bar, and an environment with a temperature of 180 DEG C for heat treatment, keep warm for 60min, and cool to room temperature at a cooling rate of 10 DEG C / min to prepare the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100.

[0073] In the experiment, the three-point bending test of the prepared 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 was carried out in a liquid nitrogen environment at-196 DEG C, and the test results are shown in Figures 1-3 Figures 1-3 Figure 3 Figure 3 P represents the loading force, and the results show that the microcrack initiation strain of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 prepared without heat treatment is 0.6%, and the microcrack initiation strain of the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 prepared by heat treatment is 0.4%, indicating that the 3D printed continuous carbon fiber reinforced thermoplastic composite material 100 obtained by heat treatment has good ultra-low temperature microcrack resistance.

[0074] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0075] In the description of the present application, "first feature" and "second feature" can include one or more features.

[0076] In the description of the present application, "a plurality of" means two or more.

[0077] ​In the description of the application, a first feature being "on", "above", or "on top" of a second feature can include the first and second features being directly in contact, or the first and second features not being directly in contact but being in contact through another feature between them.

[0078] In the description of the application, a first feature being "on", "above", and "on top" of a second feature includes the first feature being directly on, above, and on top of the second feature, or only indicating the first feature being horizontally higher than the second feature.

[0079] In the description of the application, the description of the reference terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the application. In the description of the application, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0080] Although the embodiments of the application have been shown and described, it is to be understood that various modifications, substitutions, replacements and variations can be made to these embodiments without departing from the principles and spirit of the application, and the scope of the application is defined by the claims and their equivalents.

Claims

1. A 3D printed continuous carbon fiber reinforced thermoplastic composite material, characterized in that: include: a continuous carbon fiber reinforced nylon layer, the continuous carbon fiber reinforced nylon layer comprising a plurality of sub-continuous carbon fiber reinforced nylon layers arranged along a first direction, the continuous carbon fibers in the same sub-continuous carbon fiber reinforced nylon layer extending in the same direction, and the continuous carbon fibers in two adjacent sub-continuous carbon fiber reinforced nylon layers extending in different directions, the first direction being a thickness direction of the continuous carbon fiber reinforced nylon layer; The chopped carbon fiber reinforced nylon layer includes two layers, and the two layers of the chopped carbon fiber reinforced nylon layer are arranged on opposite sides of the continuous carbon fiber reinforced nylon layer along the first direction. The chopped carbon fiber reinforced nylon layer includes at least one layer of chopped carbon fibers, and the chopped carbon fibers in the chopped carbon fiber reinforced nylon layer extend in the same direction.

2. The 3D printed continuous carbon fiber reinforced thermoplastic composite material according to claim 1, characterized in that: The included angle of the continuous carbon fibers in two adjacent sub-continuous carbon fiber reinforced nylon layers is in the range of 45° to 90°; and / or the continuous carbon fiber reinforced nylon layer includes three sub-continuous carbon fiber reinforced nylon layers arranged along the first direction.

3. The 3D printed continuous carbon fiber reinforced thermoplastic composite material according to claim 1, characterized in that: One of the two sub-continuous carbon fiber reinforced nylon layers includes six layers of continuous carbon fibers, and the other sub-continuous carbon fiber reinforced nylon layer includes twelve layers of continuous carbon fibers.

4. The 3D printed continuous carbon fiber reinforced thermoplastic composite material according to claim 1, characterized in that: The continuous carbon fiber reinforced nylon layer includes continuous carbon fiber reinforced polyamide 6-I; and / or the chopped carbon fiber reinforced nylon layer includes chopped carbon fiber reinforced polyamide 6.

5. The 3D printed continuous carbon fiber reinforced thermoplastic composite material according to claim 1, characterized in that: The porosity of the 3D printed continuous carbon fiber reinforced thermoplastic composite material is less than 1%.

6. The 3D printed continuous carbon fiber reinforced thermoplastic composite material according to claim 1, characterized in that: The microcrack initiation strain range of the 3D printed continuous carbon fiber reinforced thermoplastic composite material in an environment of -196°C is 0.4% to 0.6%.

7. A method for preparing a 3D printed continuous carbon fiber reinforced thermoplastic composite material, characterized in that: The 3D printed continuous carbon fiber reinforced thermoplastic composite material is a 3D printed continuous carbon fiber reinforced thermoplastic composite material according to any one of claims 1 to 6, and the preparation method comprises the following steps: preparing the continuous carbon fiber and the chopped carbon fiber; The continuous carbon fiber and the chopped fiber are placed in a printing device, and the sub-continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer are printed by a fused deposition modeling 3D printing process; The prepared sub-continuous carbon fiber reinforced nylon layers are stacked in a preset direction to prepare the continuous carbon fiber reinforced nylon layer, and the prepared chopped carbon fiber reinforced nylon layers are laid on opposite sides of the continuous carbon fiber reinforced nylon layer along the first direction; The continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer are placed in an argon atmosphere, an atmospheric pressure of 1 to 2 bar, and a temperature of 160°C to 210°C for heat treatment, kept warm for 60 minutes to 120 minutes, and cooled to room temperature at a cooling rate of 10°C / min to obtain the 3D printed continuous carbon fiber reinforced thermoplastic composite material.

8. The method for preparing a 3D printed continuous carbon fiber reinforced thermoplastic composite material according to claim 7, characterized in that: Before heat-treating the continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer, a vacuum bag is placed outside the continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer; After the heat treatment of the continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer is completed, the vacuum bag is removed from the outside of the continuous carbon fiber reinforced nylon layer and the chopped carbon fiber reinforced nylon layer to obtain the 3D printed continuous carbon fiber reinforced thermoplastic composite material.

9. The method for preparing a 3D printed continuous carbon fiber reinforced thermoplastic composite material according to claim 7, wherein: The thickness of the continuous carbon fiber in the first direction is 0.125 mm, and the printing filling density is 100%; and / or the thickness of the chopped carbon fiber in the first direction is 0.125 mm, and the printing filling density is 100%.

10. The method for preparing a 3D printed continuous carbon fiber reinforced thermoplastic composite material according to claim 7, wherein: The printing device includes a continuous fiber nozzle and a chopped fiber nozzle, wherein the continuous fiber nozzle is used to spray the continuous carbon fiber, and the chopped fiber nozzle is used to spray the chopped carbon fiber; Wherein, the operating temperature range of the continuous fiber nozzle is 242°C to 262°C; and / or the operating temperature range of the chopped fiber nozzle is 260°C to 280°C.

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