Patent Application
20250136518
The present invention generally relates to shape memory ceramics (SMCs) and the manufacturing techniques thereof. More particular, the present invention relates to shape memory ceramics made with four-dimensional (4D) additive-subtractive manufacturing technologies.
Unlike shape memory alloys (SMAs), the shape memory ceramics (SMCs) are a class of materials with the unique ability to recover their original shape after deformation when subjected to certain stimuli, such as temperature changes. These ceramics exhibit shape memory effects due to their ability to undergo reversible phase transformations between different crystal structures. Unlike SMAs, which are more commonly known, SMCs offer advantages such as high-temperature stability, corrosion resistance, and biocompatibility. These materials hold significant promise for various applications in aerospace, biomedical devices, actuators, and adaptive structures, where precise shape control and reliable performance are critical. However, manufacturing SMCs with complex curved structures poses significant challenges due to the intricate processing techniques required and the inherent brittleness of ceramic materials. Achieving precise control over the shape memory properties of ceramics, particularly in curved geometries, remains a major hurdle in the development and widespread adoption of these materials.
The world of additive manufacturing (AM) for building structural materials is buzzing with research. Currently, three-dimensional (3D) printing systems, a type of AM system, are speedy and scalable, but there is a catch. They often have to sacrifice resolution for speed or scalability. Luckily, a solution is on the horizon: combining AM with subtractive manufacturing (SM) to create additive-subtractive manufacturing (ASM). This concept could revolutionize 3D printing by offering rapid, precise, and scalable technology.
However, progress in 3D printing has been stymied by the high melting points of some materials. On a brighter note, inspiration from origami and kirigami techniques has propelled advancements in four-dimensional (4D) printing.
4D printing, an emerging technology, adds an additional dimension of time to traditional 3D printing by enabling materials to transform their shape or properties over time in response to external stimuli. This innovative approach holds immense potential for creating dynamic and adaptive structures that can self-assemble, self-repair, or undergo shape changes on demand. 4D printing typically involves the use of smart materials, such as shape memory polymers or hydrogels, which can be programmed to respond to stimuli such as heat, light, or moisture. While still in its early stages, 4D printing has already demonstrated applications in fields such as architecture, robotics, medicine, and aerospace, offering solutions for complex manufacturing challenges and enabling new functionalities that were previously unattainable.
Combining SMCs with 4D printing techniques presents exciting opportunities for developing advanced materials and structures with dynamic shape-changing capabilities and high-temperature resilience. However, mass production of SMCs with complex curved structures poses significant hurdles. Traditional manufacturing methods such as sintering or hot pressing are often limited in their ability to produce intricate shapes efficiently and consistently. Additive manufacturing techniques, including 3D printing, offer potential solutions for overcoming these challenges by enabling precise control over material deposition and layer-by-layer construction. Nevertheless, scaling up production to meet commercial demands while ensuring quality control and cost-effectiveness remains a key challenge that must be addressed to unlock the full potential of SMCs in diverse applications.
The present invention addresses the aforesaid shortcomings and provides significant improvements over traditional SMCs and the methods of manufacturing thereof, and the successful attempt at original/reverse and global/local multimode shape memory behaviors of ceramics opens the way to various types of self-morphing of SMCs.
The present invention relates to the martensitic phase transformation and provides a novel mechanism for SMCs. Various embodiments of the present invention provide SMCs with heterogeneity in the thermal expansion-shrinkage behavior. In some embodiments of the present invention, versatile SiOC-based SMCs are developed in a facile manner by the physical mixing of liquid silicone with varying ceramic fillers. Geometrical flexibility could be largely enhanced with 4D ASM.
Furthermore, the present invention extends the dimensions of structural SMCs from the microscale/mesoscale to the macroscale and achieved original/reverse and global/local multimode shape memory capabilities of ceramics.
In accordance with a first aspect of the present invention, a SMC is provided. The SMC comprises a first portion and a second portion. The first and second portions of the SMC are bonded. The SMC is elastomer-derived ceramic comprising silicon oxycarbide. The first portion of the SMC is treated with ultraviolet ozone (UV/ozone), and the second portion of the SMC is free from treatment of UV/ozone.
In accordance with one embodiment of the present invention, the second portion of the SMC has a plurality of grooves.
In accordance with another embodiment of the present invention, the first portion of the SMC form a plurality of strips on a surface of the second portion of the SMC.
In accordance with a second aspect of the present invention, a manufacturing method of SMC is provided. The manufacturing method comprises: providing a structural precursor comprising polydimethylsiloxane (PDMS); treating a portion of a surface of the structural precursor with UV/ozone; and processing the structural precursor using pyrolysis, so as to generate the SMC.
In accordance with one embodiment, the step of providing the structural precursor comprises: forming a first precursor using additive manufacturing; and cutting or engraving the first precursor using laser to form the structural precursor.
In accordance with another embodiment, the additive manufacturing comprises blade coating or direct ink writing.
The step of treating with UV/ozone comprises: masking a surface of the structure precursor with a laser-cut paper; and treating the masked surface with UV/ozone.
In accordance with one embodiment, after the pyrolysis process, the manufacturing method further comprises: heating the SMC in air.
In accordance with another embodiment, after the pyrolysis process, the manufacturing method further comprises: heating a portion of the SMC in air.
In accordance with yet another embodiment, after the pyrolysis process, the manufacturing method further comprises: heating at least a portion of the SMC in air using induction heating.
In accordance with various embodiments of the present invention, the aforementioned steps are performed in a turntable system with multiple stations.
In accordance with various embodiments of the present invention, the structural precursor further comprises ceramic particles (fillers) or glass particles (fillers).
In some embodiments of the present invention, the SMC has a portion that is treated with UV/ozone, and different parts of the SMC can have different material properties including thermal expansion and shrinkage, so as to utilize in 4D printing with high efficiency.
The present invention introduces a completely new fabrication mechanism for silicone matrix composites, that is, utilizing the heterogeneity in the thermal expansion-shrinkage behavior. Based on the newly developed SMC fabrication mechanism (heterogeneity in thermal expansion-shrinkage behavior), versatile SiOC-based SMCs can be developed in a facile manner by the physical mixing of liquid silicone with varying ceramic fillers.
In some embodiments of the present invention, geometrical flexibility is significantly enhanced with 4D ASM, that is, 2D/3D printing combined with laser engraving/cutting of ceramic precursors, when compared to the ceramic powder pressing methods used in previous studies. Additionally, the dimensions of structural SMCs are extended from the microscale/mesoscale to the macroscale, achieving both original/reverse and global/local multimode shape memory capabilities in ceramics. The advancements differentiate the present invention from existing studies on SMCs.
Embodiments of the invention are described in more details hereinafter with reference to the drawings, in which:
In the following description, SMCs, manufacturing methods and 4D printing thereof are set forth as preferred examples. It will be apparent to those skilled in the art that modifications, including additions and/or substitutions may be made without departing from the scope and spirit of the invention. Specific details may be omitted so as not to obscure the invention; however, the disclosure is written to enable one skilled in the art to practice the teachings herein without undue experimentation.
Color drawings are submitted with the Specification. The color drawings are necessary as the only practical medium by which aspects of the claimed subject matter may be accurately conveyed. Color drawings are the only practical medium by which to disclose the subject matter sought to be patented because the claims relate to SMC enduring heating process with controlled temperatures, where using different colors is the only feasible method to show the different temperatures on different parts or regions of the structures of the claimed subject matters.
In accordance with one aspect of the present invention, SMCs are provided. In accordance with another aspect of the present invention, the manufacturing methods of the SMCs are provided.
In one embodiment, the SMC is made of elastomer-derived ceramic (EDC), and the elastomer is processed with UV/ozone treatment before pyrolysis.
In this embodiment, before pyrolysis, a ceramic precursor is provided. The ceramic precursor comprises polydimethylsiloxane (poly(dimethylsiloxane) or PDMS), and UV/ozone treatment is applied to portion of the ceramic precursor. UV/ozone treatment is a process that involves exposing the ceramic precursor to ultraviolet (UV) light in the presence of ozone gas.
After treatment, a heterogeneous ceramic precursor is provided in the embodiment, and a treated portion of heterogeneous ceramic precursor has a coefficient of thermal expansion or a different thermal shrinkage ration that is different from the rest or remaining portion of the heterogeneous ceramic precursor. After pyrolysis, a SMC is provided, and the shape of the SMC can be modified during the pyrolysis and the following heating treatment.
In some embodiments, the ceramic precursor comprises polysiloxane (silicone oil), polyborosiloxane (PBS), polycarbosiloxane, polysilazane, apolysilazane, poly(organosilylcarbodiimide), apoly(organosilylcarbodiimide), hydrogel, or combination thereof.
Referring to
In this embodiment, the structural precursor 1 is built with elastomer material including PDMS, and the structural precursor 1 is constructed with a unique structural design, incorporating specific features that delineate the areas intended for further shape modification in the following SMC conversion.
In this embodiment, the depths of the grooves 10 are 100 km. In some other embodiments, the depths of the grooves 10 can be 200 m or 500 km. Therefore, the structural precursor 1A can be easily acquired through a subtractive manufacturing such as laser engraving.
In other words, in this embodiment, after the UV/ozone treatment, a thin film was formed on the surface 12 of the structural precursor 1A, with the film thickness adjusted by varying the processing time in an UV/ozone system.
In this step, a structural precursor demonstrating heterogeneity in the thermal expansion-shrinkage behavior across different portion is provided, and the heterogeneity led to shape transformation in the following steps. In other words, a ceramic precursor exhibiting variation in thermal expansion and shrinkage behavior across different regions is provided in this step, and it causes shape transformation in the following steps of SMC manufacturing.
More specifically, while the portion 120 of the structural precursor is treated with UV/ozone, the portion 110 of the structural precursor is shielded from the UV/ozone treatment. The portion 110 and the portion 120 are bonded, and the portion 110 has the grooves 10. The thermal expansion and shrinkage behavior of the portion 110 is different from the thermal expansion and shrinkage behavior of the portion 120.
After the UV/ozone treatment, the manufacturing method of this embodiment processes the structural precursor using pyrolysis, so as to generate a SMC 2A as shown in
In other words, the step involves a polymer-to-ceramic conversion stage, forming the SMC 2A. However, the present invention is not limited to the shape and curvature of the SMC 2A.
The SMC 2A comprises a portion 20 and a portion 21. The portion 20 and the portion 21 of the SMC 2A are bonded, and the SMC 2A is elastomer-derived ceramic comprising silicon oxycarbide.
In the steps above, the portion 20 of the SMC 2A is treated with UV/ozone, and the portion 21 of the SMC is free from treatment of UV/ozone. Therefore, the pyrolysis induced a shape transformation and formed the SMC 2A, and a 4D printing is performed.
Furthermore, the shape of the SMC 2A can be further modified with heating processing in air atmosphere. As the portion 20 and the portion 21 still possess different thermal expansion and shrinkage behavior, by performing further heating process in air atmosphere, the shape of the SMC 2A can be further modified.
In other words, after the pyrolysis, the SMC 2A is a first-generation EDC with modified shape. For further modification in its shape, at least a part of the SMC 2A can be heated in air. During the heating process, the part of the SMC 2A being heated performs a shape transformation, resulting in a second-generation EDC after the heating process.
In some embodiments, the manufacturing method further comprises heating the whole SMC in air in order to modify the shape of the SMC in every part, and the whole SMC is transformed to a second-generation EDC.
In some other embodiments, the manufacturing method further comprises heating a portion of the SMC in air in order to modify the shape of only certain parts of the SMC, and those parts of the SMC are transformed to second-generation EDCs.
In some other embodiments, the manufacturing method further comprises heating at least a portion of the SMC in air using i.e., a flame gun. The step can transform parts of the SMC or the whole SMC into second-generation EDC in order to perform a shape modification.
Therefore, the SMC 2A is well-suited for shape modification after the additive manufacture and subtractive manufacture are performed.
In accordance with one embodiment of the present invention, a 4D printing method is provided. Here, the portion 21 of the SMC 2A has a plurality of grooves. Due to the shape design of the portion 21 and the difference of the thermal expansion and shrinkage behavior, the SMC 2A is bent after the pyrolysis, and it can be bent again by a heating process.
The step of providing the structural precursor 1A comprises: forming a first precursor using additive manufacturing; and cutting or engraving the first precursor using laser to form the structural precursor.
In one embodiment, the additive manufacturing comprises blade coating, which involves running a blade over a substrate to spread a solution evenly across its surface, and it's a proper two-dimensional additive manufacturing with high efficiency.
In another embodiment, the additive manufacturing comprises direct ink writing (DIW), which involves the extrusion of a viscous ink or paste through a fine nozzle onto a substrate or build platform. DIW allows for precise control over the deposition of materials, enabling the fabrication of complex, customized object with tailored properties.
In yet another embodiment, the additive manufacturing comprises material jetting, photopolymerization, powder bed fusion or combination thereof.
In the step of forming the first precursor, the material of the additive manufacturing includes PDMS, which is a proper material for a ceramic precursor.
In some embodiments, the material of the additive manufacturing includes: polysiloxane, polyborosiloxane, polycarbosiloxane, polysilazane, poly(organosilylcarbodiimide), hydrogels, and combinations thereof.
In the step of forming the first precursor, the material of the additive manufacturing further includes zirconium dioxide nanoparticles. For example, the concentration of the zirconium dioxide nanoparticles in the material can be 10 weight percent. In some other embodiments, the concentration of the zirconium dioxide nanoparticles in the material is 20 weight percent. Therefore, the SMCs and the manufacturing method thereof can provide Zirconia-based ceramics, which have high temperature stability, high mechanical strength and toughness, chemical inertness, and biocompatibility. The zirconium dioxide nanoparticles are added to the liquid PDMS and mixed using a triple roller mill. The mixed material may be centrifuged after loading to a syringe.
In some other embodiments, the material of the additive manufacturing further includes aluminum oxynitride nanoparticles. For example, the concentration of the aluminum oxynitride nanoparticles in the material can be 50 weight percent. Therefore, the SMCs and the manufacturing method thereof can provide ceramic with enhanced hardness, transparency, thermal stability, and chemical inertness.
In some other embodiments, the material of the additive manufacturing further includes ceramic particles or glass particles, and the structural precursor comprises ceramic particles (fillers) or glass particles (fillers). Therefore, the SMC and the manufacturing method thereof can provide ceramic with different properties.
In some other embodiments, the material of the additive manufacturing further includes alumina, titania, silicon nitride, calcium oxide, silicon carbide, yttria, or aluminum nitride particles or nanoparticles.
The step of cutting or engraving the first precursor using laser provides a subtractive manufacturing with high precision. In one embodiment, silicone-based composite precursors are developed to achieve improved geometrical flexibility, and two-dimensional (2D) additive manufacturing such as blade coating or DIW is applied to generate elastomeric ceramic precursors. Meanwhile, subtractive manufacturing techniques with a high-energy beam (e.g., a laser beam) can enhance manufacturing precision, resulting in a high-resolution ASM system.
In some other embodiments, the step of cutting or engraving the first precursor may be performed with electron beam, high pressure liquids, or other controlled high energy flow.
The width of the grooves 10 in the structural precursor 1A can properly modifies the expansion and shrinkage of the ceramic in the following steps. For example, the width of the grooves 10 is 1 mm, while the depths can range from 100 μm to 500 μm. These grooves 10 can be precisely formed with the subtractive manufacturing using laser, and they can modify the expansion and shrinkage of the ceramic precisely.
In the step of UV/ozone treatment, the portion 120 is processed with UV/ozone treatment for 8 hours. Therefore, the portion 120 of can be properly formed. In the step of pyrolysis, the structural precursor is heated to 1,300° C. within 12 minutes in an induction heating furnace with an argon flow of 200 mm every minute, and the high temperature is maintained for 10 minutes. In the further step after pyrolysis, in some embodiments, the SMC is heated to 1,300° C. for 30 minutes in air with a tube furnace, so as to provide a SMC made of second-generation EDC.
Referring to
In this embodiment, the structural precursor 1B can be manufactured through 3D printing such as DIW, and the material includes PDMS and zirconium dioxide. For example, the concentration of the zirconium dioxide can be 20 weight percentage. In another example, the structural precursor 1B can be a blisk, a component comprising both rotor disk and blades as a single part, and
In this UV/ozone treatment step, precising masking is required to protect certain areas of the structural precursor 1B from exposure to UV light and ozone. The laser-cut paper 13 provide an effective solution as a mask. The laser-cut paper 13 is created by using laser cutting technology to precisely cut intricate patterns or shapes into paper sheets, and ensuring accurate masking of specific areas on the structural precursor 1B.
For example, the structural precursor 1B is planar and intersects the ground at 57°, and the structural precursor 1B is selectively exposed to UV/ozone treatment for 16 hours by masking the surface 11 with the laser-cut paper 13.
The structural precursor 1B as shown in
More specifically, during the pyrolysis, the structural precursor 1B undergoes controlled heating to 1,000° C. for 2 hours in a resistance heating furnace, followed by vacuum cooling to ambient temperature. The heating rate is maintained at 5° C. per minute and the cooling rate is 10° C. per minute.
After the cooling, a first-generation EDC is obtained. To obtain a second-generation EDC, the structural precursor 1B is subjected to additional heating. Initially, it is heated to 1,000° C., followed by further heating to 1,250° C. in an air atmosphere using a tube furnace.
In this embodiment, the SMC 2B is efficiently manufactured using 4D printing including the steps described above, and the usage of laser-cut paper 13 provide an easy-to-use, cost-effective, approach with compatibility. In an example, the structural precursor 1B as shown in
Overall, using laser-cut paper masks in conjunction with UV/ozone treatment and pyrolysis offers several advantages, including precision masking, customizability, cost-effectiveness, ease of handling, compatibility with treatment processes, reduced residue, and scalability. These advantages contribute to improved process control, efficiency, and quality in the processing of components containing PDMS.
In some embodiments of the present invention, all of the steps of the manufacturing method are performed by a single manufacturing apparatus, which can be completely automated for resource and cost effectiveness. In some other embodiments, the steps of the manufacturing method of the embodiments above can be performed in a turntable system with multiple stations. More specifically, the stations can perform different complex processing including additive manufacturing, subtractive manufacturing, UV/ozone treatment, and/or other manufacturing techniques; and every step of the manufacturing method can be performed separately and in parallel manner in one of the stations. For example, one of the stations can perform additive manufacturing, and another one of the stations can perform subtractive manufacturing, and still another one can perform UV/ozone treatment, all simultaneously, achieving streamlined mass production. Therefore, the manufacturing method of the embodiments of the present invention can be utilized in mass production.
In some other embodiments of the present invention, a manufacturing method of a SMC can further comprise deposition process. The deposition process includes physical vapor deposition, chemical vapor deposition, atomic layer deposition or combination thereof. Therefore, the SMC provided in these embodiments may further comprised layers for protection or any required function.
The SMC provide in any of the embodiments above can be applied in morphing thermal protection systems or space origami systems. Also, the SMC can be applied in on-orbit manufacturing and repairing.
The following description explains in more details the SMCs, the manufacturing and 4D printing methods thereof in accordance with the various embodiments of the present invention from different perspectives.
In accordance with one embodiment of the present invention, silicone-based composite precursors are developed to achieve improved geometrical flexibility, then blade coating (two-dimensional (2D) additive manufacturing) or direct ink writing (DIW) (3D additive manufacturing) is applied to generate elastomeric ceramic precursors. Meanwhile, subtractive manufacturing techniques with a high-energy beam (e.g., a laser beam) is used to enhance manufacturing precision, resulting in a high-resolution ASM system. The 2D/3D additive manufacturing-applied elastomeric ceramic precursors then undergo laser engraving or cutting using an optimized laser scanning strategy, which involves the precise control over laser scanning power and speed. Subsequently, the treated precursors were subjected to heat treatment to transform them into structural ceramics.
4D printing of the ceramic materials has been developed by tuning heterogeneous precursors. By integrating the elastic precursor laser cutting/engraving (EPLC/EPLE) technique and the ceramic 4D printing technique, a complex-shaped, high-resolution, cost-efficient, and environmentally friendly 4D ASM paradigm for ceramic materials is developed by the present invention. This fully embodies the integration of modern advanced manufacturing technologies with ancient ceramic arts.
By the manufacturing methods according to the embodiments of the present invention, the grooves on a structural precursor can be designed precisely. As shown in
In some embodiments, rapid one-step shape/material transformation of the structural precursors is achieved using an induction heating furnace. The material and shape transformations of the engineered heterogeneous ceramic precursors could be simultaneously achieved in as fast as a few seconds with a heating rate of 1,000° C. min−1, which is 100 times faster than the conventional resistance heating techniques. Induction heating is a highly efficient, energy-saving and environmentally friendly heating method with a wide range of applications such as metal melting, surface heat treatment and ceramic composite sintering. Induction heating converts electrical energy into thermal energy and has a high utilization rate of electrical energy, with a heating efficiency of over 90% and an energy consumption of only ⅓ of that of conventional heating.
As shown in
In some embodiments, a smooth boron nitride (BN) plate is selected as the substrate because BN is well known for its excellent thermal stability and low-friction behavior. The BN substrate is also used to reduce the friction and sticking that could lead to forces being imparted on the object during shape deformation.
The precise groove designs can be achieved using the ASM in the manufacturing method. Such precise groove designs in turn ensure versatility in building complex structures with zero, negative, positive, and mixed Gaussian curvatures. Owing to the different thermal expansion and shrinkage behaviors of the heterogeneous structural precursors, the ceramic precursor was transformed in terms of both shape and material components when subjected to thermal treatment.
Thermogravimetric analysis and differential scanning calorimetry showed that the polymer-to-ceramic transformations are achieved at 300-900° C. The Young's moduli of the PDMS/10 wt % ZrO2 and the UV/ozone microfilm are 1 and 13 MPa, respectively. The elastomer and the UV/ozone film have the average compositions of SiO1.23C1.45Zr0.05 and SiO3.13C14.81Zr0.01, respectively. The difference between the thermal expansion behaviors of the elastomers and the UV/ozone film leads to bending deformation. Moreover, the bending stiffness of the ceramic precursors and the curvatures of the resultant ceramics can be precisely tuned by modifying the depth and width of the laser-engraved grooves.
It can be demonstrated that the 4D printed ceramic structures are capable of secondary self-morphing and possess reversible reconfigurability. When the ceramic is heated in air, the heterogeneity remains in the thermal shrinkage behavior of the first-generation EDC derived from the heterogeneous precursor. For the first-generation EDCs derived from the homogeneous precursor material of PDMS/10 wt % ZrO2 without UV/ozone treatment, the linear shrinkage ratios for heating in air at 1,000° C. and 1,200° C. were 3.5% and 5.6%, respectively.
The configurability of the corresponding first-generation EDCs derived from the heterogeneous precursors subjected to UV/ozone treatment can be tuned by heating in air under different conditions. In general, the higher the heating temperature (below the morphing end point) applied on the first-generation EDCs, the more recovery to their original shape in the resultant second-generation EDCs. If the morphing end point is above the original shape memory point, the first-generation EDCs bend in the opposite direction and exhibit reverse shape memory capability. The SMCs are reversibly reconfigurable to the original planar shapes of the precursors and even to the reverse curved shapes of the first-generation EDCs under appropriate heating conditions, resulting in second-generation EDCs and original/reverse multimode shape memory behaviors of ceramics. Similarly, local heat treatment in air, such as heating in the middle or on one side, provided flexibility for the local receramization and self-morphing of first-generation EDCs, generating first/second-generation composite EDCs with multiple shapes.
In some embodiments of the present invention, before the elastomer-to-ceramic transformation, the difference in the thermal expansion coefficients of the precursor materials affects the first-stage shape transformation. After the elastomer-to-ceramic transformation, the differences in the thermal shrinkage ratios of the precursor materials can further affect a second-stage shape transformation with notable material transformation. When the resultant first-generation EDCs are heated in air, the heterogeneity in the thermal shrinkage behavior of the first-generation EDCs resulted in original/reverse multimode shape memory behaviors and receramization into the second-generation EDCs.
In short, after the heating process, the structural precursors show different curvatures because of the difference in the depth of grooves, providing the first-generation EDCs of which their curvatures are properly controlled by the formation of the grooves. The first-generation EDCs can then be transformed into second-generation EDCs through further heating process. Although engineering the expansion and shrinkage of materials is a common strategy for 4D printing, this invention represents a successful attempt at 4D printing of ceramics by recording the balance between thermal expansion and thermal shrinkage.
In
In accordance with one embodiment of the present invention, a first/second-generation composite EDC can be generated through local heating in air, i.e., heating only a portion of a first-generation EDC in air.
By heating the entirety of the first-generation EDCs 18B, second-generation EDCs 18C, 18D with different curvatures are generated depending on the heating conditions. For example, the second-generation EDC 18C is formed through heating the first-generation EDC 18B with low temperature, and the second-generation EDC 18D is formed through heating the first-generation EDC 13B with high temperature. The curvature of the second-generation EDC 18C is different from the curvature of the second-generation EDC 18C. As such, the curvature of the SMCs is properly designed by controlling the heating temperature.
On the other hand, by local heating only portions of the first-generation EDCs 18B, the method produces SMCs with different shapes. For example, by heating only the middle portion of each of the first-generation EDCs 18B, first/second-generation composite EDCs 18E are generated; and by heating only one side of each of the first-generation EDCs 18B, first/second-generation composite EDCs 18F are generated. The shape of the second-generation composite EDCs 18E is different from the shape of the second-generation composite EDCs 18F. As such the shape of the first/second-generation composite EDCs 18E, 18F are properly designed.
The ceramic 4D printing method according to the embodiments of the present invention can achieve geometrical flexibility and high morphing precision for advanced structural ceramics and can be used in high-temperature applications, such as aerospace propulsion. One derivative demonstration of the ceramic 4D printing method is illustrated in an exemplary application of the present invention with pictorial and image illustrations in
In this application, the ceramic engine turbine disk and 12 blades are 4D printed as a single piece and no assembly process was required. Through local UV/ozone exposure, blades with planar surfaces were simultaneously configured to achieve twisting deformation with high repeatability, resulting in a flower-like symmetrical structure.
As shown in
The high repeatability of the ceramic 4D printing method allows for high manufacturing precision in 3D structuring and 4D shaping. This high repeatability can be demonstrated by the 5 blades of a 4D printed all-ceramic blisk in another exemplary application of the present invention as illustrated in
The shape memory behaviors can be demonstrated with a complicated all-ceramic bladed disk (blisk) structure in yet another exemplary application as shown in
Therefore, the shape of the blades can be further adjusted through transforming the first-generation EDC to second-generation EDC. As shown in
The industrialization potential of the embodiments of the present invention can be realized by the mass production capability of heterogeneous precursor materials assisted by a multistation turntable system. To enhance manufacturing speed, blade coating is implemented using an area-by-area printing strategy instead of DIW in the line-by-line printing strategy. The EPLC method and UV/ozone surface treatment ensure manufacturing precision for 3D structuring and 4D shaping, respectively. For example, as illustrated in
The present invention broadens the application scope of high-temperature structural materials in aerospace, electronics, biomedical, and art domains, among other fields. The 4D printing method according to the embodiments of the present invention can even be applied in space exploration, such as in morphing thermal protection systems as illustrated in
As illustrated in
The proposed ASM system according to the embodiments of the present invention can be used to realize rapid, precise, and scalable manufacturing of ceramic materials by increasing the 3D printing efficiency from line-by-line printing to area-by-area printing. The laser beam technique used in SM can be extended to other controlled high-energy flows such as electron beams, ion beams, high pressure liquids, and a combination of these. The framework involving UV/ozone films on elastomeric polymers can be extended to other 2D AM materials such as metal films to achieve heterogeneous precursors.
In summary, before the elastomer-to-ceramic transformation, the difference in the thermal expansion coefficients of the precursor materials resulted in a first-stage shape transformation. After the elastomer-to-ceramic transformation, the differences in the thermal shrinkage ratios of the precursor materials resulted in a second-stage shape transformation with notable material transformation. When the resultant first-generation EDCs were heated in air, the heterogeneity in the thermal shrinkage behavior of the first-generation EDCs resulted in original/reverse multimode shape memory behaviors and receramization into the second-generation EDCs. The balance between thermal expansion and shrinkage, thus is one of the key mechanisms for the 4D printing of ceramic materials, as illustrated in
In various embodiments of the present invention, the development of SMCs starts from the martensitic phase transformation. The present invention introduces a completely new mechanism for fabricating SMCs that utilizes the heterogeneity in the thermal expansion-shrinkage behavior. Using the newly developed SMC fabrication mechanism, versatile SiOC-based SMCs can be developed in a facile manner by the physical mixing of liquid silicone with varying ceramic fillers. Geometrical flexibility is significantly enhanced with 4D ASM (2D/3D printing plus laser engraving/cutting of ceramic precursors) compared to i.e., the ceramic powder pressing used in the art. Furthermore, the dimensions of structural SMCs are extended from the microscale/mesoscale to the macroscale, achieving original/reverse and global/local multimode shape memory capabilities of ceramics. Thus, these aspects differentiate the present invention from existing manufacturing methods of SMCs. Table 1 below summarizes the differentiation of the present invention from previous works on SMCs.
The embodiments of the present invention were verified in experiments, and the experimental results are presented in the following.
For the ceramic materials, the inks for the precursors shown in
To realize the bending of heterogeneous ceramic precursors during the induction heating process, as shown in
To realize the global shape memory behaviors, as shown in
For the 4D printing and integrated shaping of the ceramic blisk, as shown in
To demonstrate the mass production capability of some embodiments, 2D AM of the ceramic precursor film (thickness: 0.5 mm) was conducted using a blade coating equipment. The precursor film was cured at 100° C. for 30 minutes and then 150° C. for 20 minutes. The surface of the precursor film was subjected to UV/ozone treatment for 50 minutes. Subsequently, the heterogeneous precursor was laser cut into a 10×10 array of designed structures within 4.5 minutes. All processing steps were controlled within 50 minutes, and with the assistance of a multistation turntable system, the mass production capability of heterogeneous precursor materials could be as efficient as 30 seconds per product, on average.
Scanning electron microscopy analysis (SEM, Tescan Clara, Tescan; Nova-Nono430, FEI) was used to characterize the structures of the ceramics and UV/ozone films on the surfaces of the ceramic precursors. To characterize the porous feature inside EDCs, a pore size analyzer (BSD-PS(M), BeiShiDe Instrument) was used to obtain N2 absorption-desorption isotherms of EDCs. Brunauer-Emmett-Teller analysis and nonlinear density functional theory was used to obtain specific surface area and pore size distribution of EDCs, respectively. A mercury intrusion porosimeter (MicroActive AutoPore V 9600, Micromeritics Instrument) was used to measure the porosity of the printed ceramic lattices. Optical profiler measurements (NPFLEX, Bruker) were obtained for mass-kirigami samples to determine the 3D morphology. Optical 3D scanning (ATOS Core 200, Abad Deghat Markazi Co.) was performed to quantify the repeatability of the blades of 4D printed all-ceramic blisk. Tension tests (Testpilot-10, Wance) of the precursors were performed using 3D printed solid samples (75 mm×10 mm×1 mm), at a displacement rate of 5 mm min−1. Nanoindentation tests (Hysitron TI980, Bruker) were performed on the surface of the UV/ozone film to obtain the modulus for FEA simulation. Thermal expansion tests (DIL402C, NETZSCH) of the precursors were performed using 3D printed solid samples (20 mm×20 mm×4 mm) that were heated to 300° C. at a rate of 5° C. min−1.
FEA was performed using commercial software ABAQUS (2016) to examine the deformation behavior during thermal expansion. The UV/ozone film was modeled as an elastic shell. The precursor and UV/ozone film were assumed to be incompressible Neo-Hookean and elastic materials, respectively. The mechanical properties and dimensions of the structures were consistent with experimental measurements. The linear thermal expansion coefficients of PDMS/10 wt % ZrO2 and PDMS/20 wt % ZrO2, before the transformation to ceramics, were 283×10−6 and 242×10−6° C.−1, respectively, according to the results of the thermal expansion tests. The moduli of PDMS/10 wt % ZrO2 and PDMS/20 wt % ZrO2 were set as 1.14 MPa and 1.56 MPa, respectively, according to the tension test results. During the loading process, a 0-10% strain was applied to obtain the corresponding Young's modulus. The thickness of the UV/ozone film exposed for 8 hours was set as 33 μm according to the SEM results, and its modulus was set as 13 MPa according to the nanoindentation results. The thickness of the UV/ozone film exposed on PDMS/20 wt % ZrO2 for 16 hours was set as 38 μm according to the SEM results, and its modulus was set as 20 MPa according to the nanoindentation results. The modulus of the equivalent film was calculated by assuming that the cross-sections had the same tensile stiffness. Before significant material transformation, the thermal expansion of the precursors dominated the shape transformation. Thus, only the thermal expansion was considered in the simulations.
The functional units and modules of the manufacturing and 4D printing methods of the SMCs in accordance with the embodiments disclosed herein may be implemented using computing devices, computer processors, or electronic circuitries including but not limited to application specific integrated circuits (ASIC), field programmable gate arrays (FPGA), microcontrollers, and other programmable logic devices configured or programmed according to the teachings of the present disclosure. Computer instructions or software codes running in the computing devices, computer processors, or programmable logic devices can readily be prepared by practitioners skilled in the software or electronic art based on the teachings of the present disclosure.
All or portions of the methods in accordance to the embodiments may be executed in one or more computing devices including server computers, personal computers, laptop computers, mobile computing devices such as smartphones and tablet computers.
The embodiments may include computer storage media, transient and non-transient memory devices having computer instructions or software codes stored therein, which can be used to program or config. The computing devices, computer processors, or electronic circuitries to perform any of the processes of the present invention. The storage media, transient and non-transient memory devices can include, but are not limited to, floppy disks, optical discs, Blu-ray Disc, DVD, CD-ROMs, and magneto-optical disks, ROMs, RAMs, flash memory devices, or any type of media or devices suitable for storing instructions, codes, and/or data.
Each of the functional units and modules in accordance with various embodiments also may be implemented in distributed computing environments and/or Cloud computing environments, wherein the whole or portions of machine instructions are executed in distributed fashion by one or more processing devices interconnected by a communication network, such as an intranet, Wide Area Network (WAN), Local Area Network (LAN), the Internet, and other forms of data transmission medium.
The foregoing description of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art.
The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated.
The present application claims priority from U.S. Provisional Patent Application No. 63/509,284 filed Jun. 21, 2023; the disclosure of which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63509284 | Jun 2023 | US |
