Wide-temperature-range shape memory composite material and 4D printing preparation method thereof

Abstract

The application discloses a wide-temperature-range shape memory composite material and a 4D printing preparation method thereof.The 4D printing preparation method comprises key steps of composite material skeleton preparation, hot extrusion forming of the composite material, post-treatment regulation and control of the functional characteristics of the composite material, and the like.The wide-temperature-range shape memory composite material prepared by the application solves the problem of large-scale production of current shape memory composite materials, can realize shape change of the shape memory alloy under multi-temperature regulation, can realize phase change at room temperature and at high temperature of 200 DEG C, and can realize shape memory functions of three shapes.Compared with traditional shape memory alloys, the wide-temperature-range shape memory composite material prepared by the application can realize more postures, thereby meeting specific functional requirements through temperature change, and has wide application prospects in the fields of medical devices, automobile industry, building and civil engineering, aerospace and the like.

Description

Technical Field

[0001] This invention belongs to the fields of shape memory alloys, composite materials and additive manufacturing, and particularly relates to a wide temperature range shape memory composite material and its 4D printing preparation method. Background Technology

[0002] Shape memory alloys have the ability to "remember" their initial shape, or to return to their previous shape when stimulated by certain stimuli such as thermomechanical or magnetic changes. Currently, researchers have discovered dozens of shape memory alloys, among which nickel-titanium based shape memory alloys possess excellent shape memory properties, good damping, good thermal stability, excellent biocompatibility, and corrosion resistance, making them widely used in various fields.

[0003] Despite the numerous advantages of nickel-titanium shape memory alloys (NTiS), their phase transition temperatures are relatively low. Ti-rich NTiS have a phase transition temperature not exceeding 100°C, while Ni-rich NTiS generally have a phase transition temperature below room temperature, significantly limiting their application range. Researchers typically increase the phase transition temperature by doping NTiS with elements such as Zr, Hf, Au, Pt, and Pd. Each of these doping elements has its advantages and disadvantages; Hf, Au, Pt, and Pd, for example, allow for a wider adjustment of the phase transition temperature, resulting in a greater shape memory effect. However, existing shape memory alloys have phase transition temperatures within a single temperature range, limiting their application. By combining room-temperature and high-temperature phase transition shape memory alloys through specific processes, it is expected that a wide-temperature-range shape memory composite material can be obtained that achieves shape memory performance at both room temperature and high temperatures.

[0004] In recent years, equipment operating in extreme environments such as outer space (temperature range of -100 to 300℃) requires shape memory alloys to maintain high hyperelasticity and stress over a wide temperature range. Some engine components require shape memory effects at both low and high temperatures, requirements that existing shape memory alloys cannot meet. To overcome the performance limitations of single shape memory alloys and expand their service applications, a composite strategy can be adopted, combining high-temperature shape memory alloys with higher phase transformation temperatures with nickel-titanium shape memory alloys, which possess excellent hyperelasticity and shape memory effects. However, the methods for combining these two alloys, ensuring good interfacial bonding quality, and coordinating their deformation are pressing issues that need to be addressed. Summary of the Invention

[0005] To overcome the shortcomings and drawbacks of existing technologies, the primary objective of this invention is to provide a wide-temperature-range shape memory composite material. This composite material enables multi-temperature-controlled shape changes in shape memory alloys, and can undergo phase transformations at both room temperature and 200°C.

[0006] The second objective of this invention is to provide a 4D printing method for fabricating wide-temperature-range shape memory composite materials. This method includes key steps such as preparing the composite material skeleton, hot extruding the composite material, and controlling the functional properties of the composite material through post-processing. This method solves the current challenges in the large-scale production and application of shape memory alloy composite materials.

[0007] The primary objective of this invention is achieved through the following technical solution:

[0008] A wide-temperature-range shape memory composite material includes a matrix phase and a reinforcing phase, wherein the volume fraction ratio of the reinforcing phase to the matrix phase is 25%–65%:75%–35%; the matrix phase material is Ni. x Ti (100-x) Phase, wherein 50≤x≤52, the reinforcing phase material is Ni. 50.4 Ti (49.6-y) X y X can be one of Au, Pt, Hf, and Pd, where 10 ≤ y ≤ 25.

[0009] Preferably, the phase transition temperature of the reinforcing phase is 130–350°C, and the phase transition temperature of the matrix phase is -20–40°C.

[0010] Preferably, the reinforcing phase is high-temperature martensite, and the matrix phase is room-temperature austenite.

[0011] Preferably, the high-temperature martensite is adaptively formed spear-shaped martensite, the matrix phase is equiaxed austenite, and the interface between the reinforcing phase and the matrix phase is equiaxed austenite.

[0012] The second objective of this invention is achieved through the following technical solution:

[0013] A 4D printing method for fabricating a wide-temperature-range shape memory composite material includes the following steps:

[0014] Step 1: Preparation of the composite material skeleton

[0015] A nickel-titanium skeleton structure was designed, and nickel-titanium metal powder was prepared by selective laser melting 4D printing. Ternary nickel-titanium metal powder was loosely packed into the nickel-titanium skeleton and cold-pressed to prepare a composite material green body.

[0016] Step 2: Hot extrusion molding of composite materials

[0017] The composite material green blank obtained in step one is kept at a temperature in an atmosphere furnace with inert gas. After the extrusion nozzle is kept at a temperature in the furnace, hot extrusion is performed to obtain a wide temperature range shape memory composite material initial product.

[0018] Step 3: Adjusting the functional properties of composite materials through post-processing

[0019] The initial product of the wide-temperature-range shape memory composite material obtained in step two is heat-treated and then quenched in ice water to prepare the wide-temperature-range shape memory composite material.

[0020] Preferably, the nickel-titanium skeleton described in step one is one of the following: a honeycomb pore structure skeleton, a cubic unit pore structure skeleton, a body-centered cubic unit pore structure skeleton, or a face-centered cubic unit pore structure skeleton. Preferably, the porosity of the nickel-titanium skeleton described in step one is 20% to 70%, the wall thickness of the nickel-titanium skeleton is 0.1 to 1 mm, and the pore diameter of the nickel-titanium skeleton pores is 0.1 to 2 mm.

[0021] Preferably, the nickel-titanium metal powder in step one is prepared by aerosol method and has a particle size of 15-53 μm; the ternary nickel-titanium metal powder is prepared by aerosol method and has a particle size of 15-275 μm.

[0022] Preferably, the ternary nickel-titanium metal powder in step one is one of nickel-titanium-gold metal powder, nickel-titanium-platinum metal powder, nickel-titanium-hafnium metal powder, and nickel-titanium-palladium metal powder.

[0023] Preferably, in step one, the selective laser melting device for nickel-titanium metal powder has a laser power of 50-500W, a spot diameter of 30-120μm, a scanning speed of 400-3000mm / s, a scanning interval of 0.02-0.2mm, and a protective atmosphere of high-purity argon during the printing process.

[0024] Preferably, in step two, the green body holding temperature is 800–1250°C, and the holding time is 10–120 min; the extrusion nozzle holding temperature is 300–800°C, and the holding time is 10–120 min; the extrusion pressure is 500–1300 MPa, the extrusion speed is 2–8 mm / s, and the hot extrusion ratio is 2–12.

[0025] Preferably, the heat treatment temperature in step three is 300–1000°C, and the holding time is 10–300 min.

[0026] This invention also provides an application of wide-temperature-range shape memory composite materials in medical device products, automotive products, building and civil engineering products, and aerospace products.

[0027] Specifically, the medical device products include cardiovascular stents, intestinal stents, spinal orthopedic rods, etc.; the automotive industry products include radiator grille valves, brake energy storage devices, and fan clutches; the building and civil engineering products include thermo-elastic refrigerators, temperature-controlled springs, elastic dampers, and shock absorbers; and the aerospace products include tire radial reinforcements, space truss assembly structures, self-deploying satellite antennas, automatic exhaust nozzles, flexible wings, and pipe fittings.

[0028] The principle of the wide-temperature-range shape memory composite material preparation method of the present invention is as follows:

[0029] This invention combines NiTiAu, NiTiPt, NiTiHf, and NiTiPd alloys, which have higher phase transformation temperatures and higher hardness, with NiTi alloys, which have large strain, high recovery rate, and low phase transformation temperatures. This results in a composite material exhibiting shape memory effect over a wider temperature range, including both high and low temperatures. The hot extrusion process ensures that both phases undergo plastic deformation in a solid state. Under thermo-mechanical coupling, the large plastic deformation and element diffusion significantly improve density, resulting in excellent interfacial metallurgical bonding.

[0030] The present invention has the following advantages and effects compared with the prior art:

[0031] (1) The 4D printing preparation method of the wide temperature range shape memory composite material of the present invention uses selective laser melting 4D printing technology to prepare a nickel-titanium matrix skeleton material, fills it with loosely packed multi-element nickel-titanium metal powder, and then performs hot extrusion hyperplastic molding of the wide temperature range shape memory composite material. A schematic diagram of the hot extrusion hyperplastic molding process used in the present invention is attached. Figure 1 As shown in the figure, the 4D printing method for wide-temperature-range shape memory composite materials described in this invention can precisely control the arrangement of the high-temperature and low-temperature phases, and artificially pre-set the structure to control functional changes, thereby improving the design freedom of wide-temperature-range shape memory composite materials. This invention provides a framework for realizing composite materials with shape memory alloys that can control multiple shape changes at various temperatures.

[0032] (2) The 4D printing preparation method of the wide temperature range shape memory composite material described in this invention also involves a hot extrusion superplastic molding process. The hot extrusion superplastic molding process ensures that both phase materials are plastically deformed in a solid state. Under the action of thermo-mechanical coupling, the density is greatly improved through large plastic deformation and element diffusion, and a good interfacial metallurgical bond is obtained.

[0033] (3) The wide temperature range shape memory composite material prepared by the present invention can realize the shape change of shape memory alloy in a wide temperature range, and can undergo phase change at room temperature and at high temperature of 200℃.

[0034] (4) The matrix phase of the wide temperature range shape memory composite material described in this invention is room temperature austenite and the reinforcing phase is high temperature martensite. Compared with traditional shape memory alloys, it has an additional temperature range of phase transformation, realizing the memory of three shapes. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the hot extrusion hyperplastic molding process;

[0036] Figure 2 This is the DSC image of the NiTi-NiTiHf wide-temperature-range shape memory composite material of Example 1;

[0037] Figure 3 This is a schematic diagram of the shape change of the NiTi-NiTiHf wide-temperature-range shape memory composite material at different temperatures in Example 1;

[0038] Figure 4 This is a microstructure diagram of the NiTi-NiTiHf wide-temperature-range shape memory composite material from Example 2;

[0039] Figure 5 This is the DSC diagram of the NiTi skeleton hot extruded material in Comparative Example 1;

[0040] Figure 6 This is the DSC diagram of the hot-extruded NiTiHf powder material of Comparative Example 2. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0042] Example 1

[0043] The wide-temperature-range shape memory composite material described in this embodiment includes the following preparation steps:

[0044] Step 1: Preparation of the composite material skeleton

[0045] Ni with a particle size of 15–53 μm 51.2 Ti 48.8 The powder was designed with a honeycomb structure of nickel-titanium framework with a porosity of 60%. The nickel-titanium framework wall thickness was 0.3 mm, and the pore size of the nickel-titanium framework pores was 0.4 mm. Ni 51.2 Ti 48.8 The powder was processed using a selective laser melting device with a laser power of 180W. The laser spot diameter for 4D printing was 80μm, the scanning speed was 1400mm / s, and the scanning interval was 0.08mm. The protective atmosphere during the printing process was high-purity argon. Ni particles with a diameter of 15–75μm were used. 50.4 Ti 29.6 Hf 20Powder is loosely packed into a skeleton and cold-pressed to form a composite material cold-pressed green body;

[0046] Step 2: Hot extrusion molding of composite materials

[0047] The cold-pressed green blank obtained in step one is held at 1000°C for 30 minutes in an argon atmosphere furnace, held at 480°C for 30 minutes at an extrusion nozzle, and then hot-extruded at 1000°C with an extrusion ratio of 4:1 for the feed cross-sectional area to the discharge cross-sectional area to obtain a wide-temperature-range shape memory composite material initial product.

[0048] Step 3: Adjusting the functional properties of the initial product of wide-temperature-range shape memory composite material through post-processing.

[0049] The initial product of the wide-temperature-range shape memory composite material obtained in step two was sealed in a diamond-quartz glass tube under high-purity argon atmosphere and subjected to a heat treatment process of holding at 550℃ for 120 min, followed by ice-water quenching to prepare the wide-temperature-range shape memory composite material. DSC test results show that, compared to the initial product of the hot-extruded wide-temperature-range shape memory composite material, the heat-treated wide-temperature-range shape memory composite material exhibits a high-temperature phase transition peak at 200℃, achieving the target requirement of a two-stage phase transition (e.g., ...). Figure 2 (As shown); Compression tests on the wide-temperature-range shape memory composite material prepared in this embodiment show that the room temperature compressive strength of the composite material can reach 2837 MPa, and the high-temperature compressive strength at 200℃ can reach 2843 MPa. The curvature of the sheet sample is 0 at -100℃ to 0℃, and the curvature of the sheet sample is 40 μm when the temperature reaches 25℃. -1 When the temperature reaches 200℃, the curvature of the sheet-like sample is 157m. -1 (like Figure 3 (As shown).

[0050] Example 2

[0051] The wide-temperature-range shape memory composite material described in this embodiment includes the following preparation steps:

[0052] Step 1: Preparation of the composite material skeleton

[0053] Ni with a particle size of 15–53 μm 51.2 Ti 48.8 The powder was designed with a honeycomb structure of nickel-titanium framework with a porosity of 50%. The nickel-titanium framework wall thickness was 0.2 mm, and the pore size of the nickel-titanium framework pores was 0.5 mm. 51.2 Ti 48.8The powder was processed using a selective laser melting device with a laser power of 250W. The laser spot diameter for 4D printing was 80μm, the scanning speed was 1600mm / s, and the scanning interval was 0.12mm. The protective atmosphere during the printing process was high-purity argon. Ni particles with a diameter of 105–175μm were used. 50.4 Ti 29.6 Hf 20 Powder is loosely packed into a skeleton and cold-pressed to prepare a composite material green body;

[0054] Step 2: Hot extrusion molding of composite materials

[0055] The cold-pressed green body obtained in step one is held at 1050°C for 30 minutes in an argon atmosphere furnace, and then held at 500°C for 30 minutes at an extrusion nozzle. Hot extrusion is then performed at 1050°C with an extrusion ratio of 6:1 between the feed cross-sectional area and the discharge cross-sectional area to obtain a primary product of a wide temperature range shape memory composite material.

[0056] Step 3: Adjust the functional properties of composite materials through post-processing.

[0057] The composite material obtained in step two was sealed in a diamond-quartz glass tube under high-purity argon atmosphere and subjected to a heat treatment process of holding at 400℃ for 60 min followed by ice-water quenching to prepare a wide-temperature-range shape memory composite material. DSC test results showed that, compared to the original hot-extruded state, the high-temperature phase transformation at 200℃ was not fully activated after this heat treatment. Compression tests showed that the room temperature compressive strength of the composite material reached 2456 MPa, and the high-temperature compressive strength at 200℃ reached 2498 MPa. The curvature of the sheet sample was 0 at -100℃ to 0℃, and 20 μm at 25℃. -1 When the temperature reaches 200℃, the curvature of the sheet-like sample is 55m. -1 .

[0058] Example 3

[0059] The wide-temperature-range shape memory composite material described in this embodiment includes the following preparation steps:

[0060] Step 1: Preparation of the composite material skeleton

[0061] Ni with a particle size of 15–53 μm 51.2 Ti 48.8 The powder was designed with a cubic unit pore structure of nickel-titanium framework with a porosity of 40%. The nickel-titanium framework wall thickness was 0.1 mm, and the pore diameter of the nickel-titanium framework was 0.8 mm. 51.2 Ti 48.8The powder was processed using a selective laser melting device with a laser power of 150W. The laser spot diameter for 4D printing was 80μm, the scanning speed was 1200mm / s, and the scanning interval was 0.15mm. The protective atmosphere during the printing process was high-purity argon. Ni particles with a diameter of 105–175μm were used. 50.4 Ti 29.6 Hf 20 Powder is loosely packed into a skeleton and cold-pressed to prepare a composite material green body;

[0062] Step 2: Hot extrusion molding of composite materials

[0063] The cold-pressed green body obtained in step one is held at 1200°C for 60 minutes in an argon atmosphere furnace, and then held at 500°C for 60 minutes at an extrusion nozzle. Hot extrusion is then performed at 1200°C with an extrusion ratio of 8:1 between the feed cross-sectional area and the discharge cross-sectional area to obtain a primary product of a wide temperature range shape memory composite material.

[0064] Step 3: Adjust the functional properties of composite materials through post-processing.

[0065] The composite material obtained in step two was sealed in a diamond-quartz glass tube under high-purity argon atmosphere and subjected to a heat treatment process of holding at 700℃ for 240 min followed by ice-water quenching to prepare a wide-temperature-range shape memory composite material. DSC test results showed that, compared to the original hot-extruded state, the high-temperature phase transformation was not fully activated after this heat treatment. Compression tests showed that the room temperature compressive strength of the composite material reached 2199 MPa, and the high-temperature compressive strength at 200℃ reached 2260 MPa. The curvature of the sheet sample was 0 at -100℃ to 0℃, and reached 35 μm at 25℃. -1 When the temperature reaches 200℃, the curvature of the sheet-like sample is 80m. -1 .

[0066] Example 4

[0067] The wide-temperature-range shape memory composite material described in this embodiment includes the following preparation steps:

[0068] Step 1: Preparation of the composite material skeleton

[0069] Ni with a particle size of 15–53 μm 50.4 Ti 49.6 The powder was designed with a cubic unit pore structure of nickel-titanium framework with a porosity of 60%. The nickel-titanium framework wall thickness was 0.4 mm, and the pore diameter of the nickel-titanium framework was 0.7 mm. 50.4 Ti 49.6The powder was processed using a selective laser melting device with a laser power of 150W. The laser spot diameter for 4D printing was 80μm, the scanning speed was 1400mm / s, and the scanning interval was 0.08mm. The protective atmosphere during the printing process was high-purity argon. Ni particles with a diameter of 15–75μm were used. 50.4 Ti 29.6 Hf 20 Powder is loosely packed into a skeleton and cold-pressed to form a composite material cold-pressed green body;

[0070] Step 2: Hot extrusion molding of composite materials

[0071] The cold-pressed green blank obtained in step one is held at 1250°C for 20 minutes in an argon atmosphere furnace, held at 500°C for 20 minutes at an extrusion nozzle, and then hot-extruded at 1250°C with an extrusion ratio of 6:1 for the feed cross-sectional area to the discharge cross-sectional area to obtain a wide temperature range shape memory composite material initial product.

[0072] Step 3: Adjusting the functional properties of composite materials through post-processing

[0073] The composite material obtained in step two was sealed in a diamond-quartz glass tube under high-purity argon atmosphere and subjected to a heat treatment process of holding at 550℃ for 240 min followed by ice-water quenching to prepare a wide-temperature-range shape memory composite material. DSC test results showed that, compared to the original hot-extruded state, the 200℃ high-temperature phase transition peak was excited after heat treatment, achieving the target two-stage phase transition requirement. Compression tests showed that the room temperature compressive strength of the composite material reached 2806 MPa, and the high-temperature compressive strength at 200℃ reached 2859 MPa. The curvature of the sheet sample was 0 at -100℃ to 0℃, and 45 μm at 25℃. -1 When the temperature reaches 200℃, the curvature of the sheet-like sample is 145m. -1 .

[0074] Example 5

[0075] The wide-temperature-range shape memory composite material described in this embodiment includes the following preparation steps:

[0076] Step 1: Preparation of the composite material skeleton

[0077] Ni with a particle size of 15–53 μm 51.2 Ti 48.8 The powder was designed with a body-centered cubic pore structure of nickel-titanium framework with a porosity of 50%. The nickel-titanium framework wall thickness was 0.5 mm, and the pore diameter of the nickel-titanium framework was 1 mm. 51.2 Ti 48.8The powder was processed using a selective laser melting device with a laser power of 180W. The laser spot diameter for 4D printing was 80μm, the scanning speed was 1400mm / s, and the scanning interval was 0.08mm. The protective atmosphere during the printing process was high-purity argon. Ni particles with a diameter of 15–75μm were used. 50.4 Ti 34.6 Hf 15 Powder is loosely packed into a skeleton and cold-pressed to prepare a composite material green body;

[0078] Step 2: Hot extrusion molding of composite materials

[0079] The cold-pressed green body obtained in step one is held at 1150°C for 30 minutes in an argon atmosphere furnace, held at 500°C for 30 minutes at an extrusion nozzle, and then hot-extruded at 1150°C with an extrusion ratio of 4:1 for the feed cross-sectional area to the discharge cross-sectional area to obtain a primary product of wide temperature range shape memory composite material.

[0080] Step 3: Adjusting the functional properties of composite materials through post-processing

[0081] The composite material obtained in step two was sealed in a diamond-quartz glass tube under high-purity argon atmosphere and subjected to a heat treatment process of holding at 550℃ for 60 min followed by ice-water quenching to prepare a wide-temperature-range shape memory composite material. DSC test results showed that, compared to the original hot-extruded state, the 200℃ high-temperature phase transition peak was activated after heat treatment, achieving the target two-stage phase transition requirement. Compression tests showed that the room temperature compressive strength of the composite material reached 3207 MPa, and the high-temperature compressive strength at 200℃ reached 3199 MPa. The curvature of the sheet sample was 0 at -100℃ to 0℃, and 38 μm at 25℃. -1 When the temperature reaches 200℃, the curvature of the sheet-like sample is 136m. -1 .

[0082] Example 6

[0083] The wide-temperature-range shape memory composite material described in this embodiment includes the following preparation steps:

[0084] Step 1: Preparation of the composite material skeleton

[0085] Ni with a particle size of 15–53 μm 51.2 Ti 48.8 The powder was designed with a body-centered cubic pore structure of nickel-titanium framework with a porosity of 40%. The nickel-titanium framework wall thickness was 0.6 mm, and the pore size of the nickel-titanium framework was 1.2 mm. 51.2 Ti 48.8The powder was processed using a selective laser melting device with a laser power of 200W. The laser spot diameter for 4D printing was 80μm, the scanning speed was 1600mm / s, and the scanning interval was 0.10mm. The protective atmosphere during the printing process was high-purity argon. Ni particles with a diameter of 105–175μm were used. 50.4 Ti 29.6 Pd 20 Powder is loosely packed into a skeleton and cold-pressed to prepare a composite material green body;

[0086] Step 2: Hot extrusion molding of composite materials

[0087] The cold-pressed green body obtained in step one is held at 900°C for 30 minutes in an argon atmosphere furnace, held at 450°C for 30 minutes at an extrusion nozzle, and then hot-extruded at 900°C with the feed material and an extrusion ratio of 4:1 between the feed cross-sectional area and the discharge cross-sectional area to obtain a wide-temperature-range shape memory composite material initial product.

[0088] Step 3: Adjusting the functional properties of composite materials through post-processing

[0089] The composite material obtained in step two was sealed in a diamond-quartz glass tube under high-purity argon atmosphere and subjected to a heat treatment process of holding at 400℃ for 120 min followed by ice-water quenching to prepare a wide-temperature-range shape memory composite material. DSC test results showed that, compared to the original hot-extruded state, the high-temperature phase transformation at 200℃ was not fully activated after this heat treatment. Compression tests showed that the room temperature compressive strength of the composite material reached 2239 MPa, and the high-temperature compressive strength at 200℃ reached 2301 MPa. The curvature of the sheet sample was 0 at -100℃ to 0℃, and 46 μm at 25℃. -1 When the temperature reaches 200℃, the curvature of the sheet-like sample is 77m. -1 .

[0090] Example 7

[0091] The wide-temperature-range shape memory composite material described in this embodiment includes the following preparation steps:

[0092] Step 1: Preparation of the composite material skeleton

[0093] Ni with a particle size of 15–53 μm 51.2 Ti 48.8 The powder was designed with a face-centered cubic unit cell structure of nickel-titanium framework with a porosity of 60%. The nickel-titanium framework wall thickness was 0.2 mm, and the pore size of the nickel-titanium framework pores was 0.9 mm. 51.2 Ti 48.8The powder was processed using a selective laser melting device with a laser power of 180W. The laser spot diameter for 4D printing was 80μm, the scanning speed was 1600mm / s, and the scanning interval was 0.08mm. The protective atmosphere during the printing process was high-purity argon. Ni particles with a diameter of 15–75μm were used. 50.4 Ti 29.6 Au 20 Powder is loosely packed into a skeleton and cold-pressed to prepare a composite material green body;

[0094] Step 2: Hot extrusion molding of composite materials

[0095] The cold-pressed green body obtained in step one is held at 1100°C for 60 minutes in an argon atmosphere furnace, held at 500°C for 60 minutes at an extrusion nozzle, and then hot-extruded at 1100°C with an extrusion ratio of 8:1 for the feed cross-sectional area to the discharge cross-sectional area to obtain a wide-temperature-range shape memory composite material initial product.

[0096] Step 3: Adjusting the functional properties of composite materials through post-processing

[0097] The composite material obtained in step two was sealed in a diamond-quartz glass tube under high-purity argon atmosphere and subjected to a heat treatment process of holding at 700℃ for 240 min followed by ice-water quenching to prepare a wide-temperature-range shape memory composite material. DSC test results showed that, compared to the original hot-extruded state, the high-temperature phase transformation at 200℃ was not fully activated after this heat treatment. Compression tests showed that the room temperature compressive strength of the composite material reached 2993 MPa, and the high-temperature compressive strength at 200℃ reached 2801 MPa. The curvature of the sheet sample was 0 at -100℃ to 0℃, and 42 μm at 25℃. -1 When the temperature reaches 200℃, the curvature of the sheet-like sample is 122m. -1 .

[0098] Example 8

[0099] The wide-temperature-range shape memory composite material described in this embodiment includes the following preparation steps:

[0100] Step 1: Preparation of the composite material skeleton

[0101] Ni with a particle size of 15–53 μm 51.2 Ti 48.8 The powder was designed with a face-centered cubic unit cell structure of nickel-titanium framework with a porosity of 40%. The nickel-titanium framework wall thickness was 0.7 mm, and the pore size of the nickel-titanium framework was 0.8 mm. 51.2 Ti 48.8The powder was processed using a selective laser melting device with a laser power of 150W. The laser spot diameter for 4D printing was 80μm, the scanning speed was 1400mm / s, and the scanning interval was 0.1mm. The protective atmosphere during the printing process was high-purity argon. Ni particles with a diameter of 105–175μm were used. 50.4 Ti 29.6 Pt 20 Powder is loosely packed into a skeleton and cold-pressed to prepare a composite material green body;

[0102] Step 2: Hot extrusion molding of composite materials

[0103] The cold-pressed green blank obtained in step one is held at 1100°C for 20 minutes in an argon atmosphere furnace, held at 450°C for 20 minutes at an extrusion nozzle, and then hot-extruded at 1100°C with an extrusion ratio of 6:1 for the feed cross-sectional area to the discharge cross-sectional area to obtain a wide-temperature-range shape memory composite material initial product.

[0104] Step 3: Adjusting the functional properties of composite materials through post-processing

[0105] The composite material obtained in step two was sealed in a diamond-quartz glass tube under high-purity argon atmosphere and subjected to a heat treatment process of holding at 400℃ for 60 min followed by ice-water quenching to prepare a wide-temperature-range shape memory composite material. DSC test results showed that, compared to the original hot-extruded state, the high-temperature phase transformation at 200℃ was not fully activated after this heat treatment. Compression tests showed that the room temperature compressive strength of the composite material reached 2546 MPa, and the high-temperature compressive strength at 200℃ reached 2601 MPa. The curvature of the sheet sample was 0 at -100℃ to 0℃, and 20 μm at 25℃. -1 When the temperature reaches 200℃, the curvature of the sheet-like sample is 65m. -1 .

[0106] Comparative Example 1

[0107] This comparative example provides a Ni 51.2 Ti 48.8 The preparation method of the skeleton hot extruded material, except for the Ni in step one of Example 1, involves... 50.4 Ti 29.6 Hf 20 The powder was replaced with Ni with a particle size of 15–53 μm. 51.2 Ti 48.8 The powder, and everything else, are the same as in Example 1.

[0108] The Ni prepared in this comparative example 51.2 Ti 48.8 The skeleton hot-extruded material contains only a single type of room-temperature austenite, and its DSC curve is as follows: Figure 5 As shown, the DSC test results indicate that Ni51.2 Ti 48.8 The hot-extruded skeleton material undergoes a phase transition at 30℃, but only within a room-temperature phase transition temperature range, and cannot undergo a high-temperature phase transition. The curvature of the sheet-like sample is 0℃ between -100℃ and 0℃, but reaches 40m at 30℃. -1 When the temperature reaches 200℃, the curvature of the sheet-like sample is 40m. -1 Because there is no NiTiHf reinforcing phase, the material lacks high-temperature martensite, meaning it lacks a high-temperature phase transformation temperature range.

[0109] Comparative Example 2

[0110] This comparative example provides a Ni 50.4 Ti 29.6 Hf 20 The specific steps for preparing hot-extruded powder materials are as follows:

[0111] Step 1: Hot extrusion molding of Ni 50.4 Ti 29.6 Hf 20

[0112] Ni 50.4 Ti 29.6 Hf 20 Ni powder was loosely packed into a steel sleeve and then cold-pressed and pre-formed to produce Ni. 50.4 Ti 29.6 Hf 20 The green billet was held at 1000°C for 30 min in an argon atmosphere furnace, then held at 480°C for 30 min at an extrusion nozzle, and finally hot-extruded at 1000°C with an extrusion ratio of 4:1 (feed to discharge cross-sectional area) to obtain Ni. 50.4 Ti 29.6 Hf 20 Primary products of hot-extruded powder materials;

[0113] Step 2: Adjusting Ni through post-processing 50.4 Ti 29.6 Hf 20 Functional characteristics of primary products of hot extruded powder materials

[0114] The Ni obtained in step one 50.4 Ti 29.6 Hf 20 Ni was prepared by sealing the initial product of hot-extruded powder material in a diamond-quartz glass tube under high-purity argon atmosphere, followed by a heat treatment process of holding at 550℃ for 120 minutes and then quenching in ice water. 50.4 Ti 29.6 Hf 20 Powder hot extrusion material.

[0115] The Ni prepared in this comparative example 50.4Ti 29.6 Hf 20 Powder hot extrusion materials contain only a single type of high-temperature martensite, and their DSC curves are as follows: Figure 6 As shown, the DSC test results indicate that Ni 50.4 Ti 29.6 Hf 20 Powder hot extrusion materials undergo a phase transition at 300℃, but only within a single high-temperature phase transition temperature range, and cannot undergo a room-temperature phase transition; compression experiments show that Ni 50.4 Ti 29.6 Hf 20 The hot extrusion compressive strength of the powder is only 1646 MPa, while the high-temperature compressive strength at 200℃ is 1725 MPa. The curvature of the sheet-like sample is 0 at -100℃ to 0℃, 0 at 25℃, and 60 μm at 300℃. -1 Because there is no Ni 51.2 Ti 48.8 The matrix material lacks a room temperature phase transition temperature range due to the loss of Ni. 51.2 Ti 48.8 The reinforcing effect of the matrix resulted in the lower strength of the material prepared in this comparative example.

[0116] Comparative Example 3

[0117] This comparative example provides a Ni 51.2 Ti 48.8 The preparation method for hot-extruded bar materials is as follows:

[0118] Step 1: Hot extrusion molding of Ni 51.2 Ti 48.8 Material

[0119] cast Ni 51.2 Ti 48.8 The bar stock was loaded into a steel cladding and held at 1000°C for 30 minutes in an argon-filled furnace, followed by holding at 480°C for 30 minutes at an extrusion nozzle. Hot extrusion was then performed at 1000°C with an extrusion ratio of 4:1 (feed to discharge cross-sectional area) to obtain Ni. 51.2 Ti 48.8 Primary products of hot extruded bar stock;

[0120] Step 2: Adjusting Ni through post-processing 51.2 Ti 48.8 Functional characteristics of primary products of hot extruded bar stock

[0121] The Ni obtained in step one 51.2 Ti 48.8Ni was prepared by heat-treating the initial product of hot-extruded bar stock by sealing it in a diamond-quartz glass tube under high-purity argon atmosphere, holding it at 550℃ for 120 minutes, and then quenching it in ice water. 51.2 Ti 48.8 Hot extrusion of bar stock.

[0122] The Ni prepared in this comparative example 51.2 Ti 48.8 Hot-extruded bar stock contains only a single type of room-temperature austenite. DSC testing results indicate that Ni... 51.2 Ti 48.8 The hot-extruded skeleton material undergoes a phase transition at 25℃, but only within a room-temperature phase transition temperature range, and cannot undergo a high-temperature phase transition. The curvature of the sheet-like sample is 0℃ between -100℃ and 0℃, but reaches 45m at 25℃. -1 When the temperature reaches 200℃, the curvature of the sheet-like sample is 45m. -1 Because there is no NiTiHf reinforcing phase, the material lacks high-temperature martensite, meaning it lacks a high-temperature phase transformation temperature range.

[0123] Comparative Example 4

[0124] This comparative example provides a Ni 50.4 Ti 29.6 Hf 20 The preparation method for hot-extruded bar materials is as follows:

[0125] Step 1: Hot extrusion molding of Ni 50.4 Ti 29.6 Hf 20 Material

[0126] cast Ni 50.4 Ti 29.6 Hf 20 The bar stock was loaded into a steel cladding and held at 1000°C for 30 minutes in an argon-filled furnace, followed by holding at 480°C for 30 minutes at an extrusion nozzle. Hot extrusion was then performed at 1000°C with an extrusion ratio of 4:1 (feed to discharge cross-sectional area) to obtain Ni. 50.4 Ti 29.6 Hf 20 Primary products of hot extruded bar stock;

[0127] Step 2: Adjusting Ni through post-processing 50.4 Ti 29.6 Hf 20 Functional characteristics of primary products of hot extruded bar stock

[0128] The Ni obtained in step one 50.4 Ti 29.6 Hf 20Ni was prepared by heat treatment of the initial product of hot extruded bar stock, which was then sealed in a tube with diamond quartz glass under high-purity argon atmosphere and held at 550℃ for 120 minutes, followed by ice-water quenching. 50.4 Ti 29.6 Hf 20 Hot extrusion of bar stock.

[0129] The Ni prepared in this comparative example 50.4 Ti 29.6 Hf 20 Hot-extruded bar stock contains only a single type of high-temperature martensite. DSC test results show that Ni... 50.4 Ti 29.6 Hf 20 Hot-extruded bar materials undergo a phase transition at 250℃, but only within a single high-temperature phase transition range; room-temperature phase transitions are not possible. Compression experiments show that Ni... 50.4 Ti 29.6 Hf 20 The hot extrusion compressive strength of the bar stock is only 2046 MPa, while the high-temperature compressive strength at 200℃ is 2125 MPa. The curvature of the sheet sample is 0 at -100℃ to 0℃, 0 at 25℃, and 96 μm at 250℃. -1 Since there is no NiTi matrix, the material lacks a room temperature phase transition temperature range. Due to the loss of the reinforcing effect of the NiTi matrix, the strength of the material prepared in this comparative example is relatively low.

[0130] In summary, the wide-temperature-range shape memory composite material and its 4D printing preparation method provided by this invention have significant advantages in preparing shape memory composite material products. The prepared wide-temperature-range shape memory composite material can undergo phase change at room temperature and can also achieve phase change at high temperature. At the same time, it has good room temperature compressive strength and high temperature compressive strength, and can achieve the memory of three shapes.

[0131] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A 4D printing method for fabricating a wide-temperature-range shape memory composite material, characterized in that, The wide-temperature-range shape memory composite material comprises a matrix phase and a reinforcing phase, wherein the volume fraction ratio of the reinforcing phase to the matrix phase is 25%~65%:75%~35%; the matrix phase material is Ni. x Ti （100-x） Phase, wherein 50≤x≤52, the reinforcing phase material is Ni. 50.4 Ti （49.6-y） X y , where X is one of Au, Pt, Hf, and Pd, and 10 ≤ y ≤ 25; The phase transition temperature of the enhanced phase is 130~350℃, and the phase transition temperature of the matrix phase is -20~40℃; The reinforcing phase is high-temperature martensite, and the matrix phase is room-temperature austenite; The high-temperature martensite is adaptively formed spear-shaped martensite, the matrix phase is equiaxed austenite, and the interface between the reinforcing phase and the matrix phase is equiaxed austenite. The 4D printing preparation method of the wide temperature range shape memory composite material specifically includes the following steps: Step 1: Preparation of composite material green body A nickel-titanium framework structure was designed, and nickel-titanium metal powder was used to prepare the framework by selective laser melting 4D printing. Ternary nickel-titanium-based metal powder was loosely packed into the nickel-titanium framework and cold-pressed to prepare a composite material green body. The laser power of the nickel-titanium metal powder in the selective laser melting 4D printing was 50~500W; the spot diameter was 30~120μm; the scanning speed was 400~3000mm / s; the scanning spacing was 0.02~0.2mm; the protective atmosphere during the printing process was high-purity argon; the porosity of the nickel-titanium framework was 20%~70%, the wall thickness of the nickel-titanium framework was 0.1~1mm, and the pore size of the nickel-titanium framework pores was 0.1~2mm. Step 2: Hot extrusion molding of composite materials The composite material green blank obtained in step one is kept at a temperature in a furnace with an inert gas atmosphere. After the extrusion nozzle is kept at a temperature in the furnace, hot extrusion is performed to obtain a wide-temperature-range shape memory composite material initial product. The holding temperature of the composite material green blank is 800~1250℃, and the holding time is 10min~120min. The holding temperature of the extrusion nozzle is 300~800℃, and the holding time is 10min~120min. The extrusion pressure is 500~1300 MPa, the extrusion speed is 2~8 mm / s, and the hot extrusion ratio is 2~12. Step 3: Post-processing to regulate the functional properties of composite materials The initial product of the wide-temperature-range shape memory composite material obtained in step two is heat-treated and then quenched in ice water to prepare the wide-temperature-range shape memory composite material.

2. The 4D printing preparation method of the wide temperature range shape memory composite material according to claim 1, characterized in that, The nickel-titanium skeleton described in step one is a honeycomb pore structure skeleton or a cubic unit pore structure skeleton.

3. The 4D printing preparation method of the wide temperature range shape memory composite material according to claim 2, characterized in that, When the nickel-titanium framework is a cubic unit porous structure framework, the cubic unit porous structure framework is a body-centered cubic unit porous structure framework or a face-centered cubic unit porous structure framework.

4. The 4D printing preparation method of the wide temperature range shape memory composite material according to claim 1, characterized in that, The nickel-titanium metal powder mentioned in step one is prepared by aerosol method, with a particle size of 15~53μm; the ternary nickel-titanium-based metal powder is prepared by aerosol method, with a particle size of 15~275μm.

5. The 4D printing preparation method of the wide temperature range shape memory composite material according to claim 1, characterized in that, The heat treatment temperature in step three is 300~1000℃, and the holding time is 10min~300min.

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