Precision Ceramics
Application of precision ceramics in aerospace field
Ceramic parts have broad application prospects in the field of aerospace manufacturing due to their high strength, low density, high temperature resistance, and corrosion resistance. At present, ceramic parts used in the aerospace field can be divided into mechanical parts (such as turbine integral blisks, nose cover, wing leading edge and flaps, missile nozzles and nose cones, etc.) and functional parts (such as missiles, radomes and antenna windows of satellites, etc.). However, the traditional manufacturing methods of ceramic parts have problems such as long cycle, high cost, reliance on molds, and difficulty in manufacturing complex structures, which greatly limit the application of ceramic parts in the aerospace field. Additive manufacturing technology is a method of directly manufacturing parts driven by 3D data based on the principle of "discrete-buildup" forming. Compared with traditional manufacturing methods, additive manufacturing technology has the advantages of high design freedom, short product development cycle, and low manufacturing cost, and can quickly manufacture complex structural ceramic parts without molds. Zhongwei Precision not only solves the above problems, but the products have also been applied in batches. For details, please contact us by email. This article briefly outlines the potential applications of ceramic parts additive manufacturing technology in the aerospace field and the problems that need to be solved.
1. Potential application directions of ceramic additive manufacturing technology in the aerospace field:
Compared with traditional manufacturing methods, additive manufacturing technology has the characteristics of high design freedom, short product development cycle, and low manufacturing cost, and can quickly manufacture complex structural ceramic parts without molds. Under the background that aircraft parts tend to be lightweight, integrated, precise, and structure-function integration, the additive manufacturing technology of ceramic parts is considered to be one of the key technologies in the technological transformation of aerospace manufacturing due to its unique advantages. For the manufacture of several types of key parts.
①Lightweight and integrated ceramic parts
The assembly structure of traditional metal parts is transformed into the integrated manufacturing of ceramic parts, and the weight reduction of the fusion part can be realized, which can improve its work efficiency and prolong its service life. Taking aero engines as an example, the key to developing a new type of high thrust-to-weight ratio engine lies in the materials and manufacturing technologies used. Ceramic materials, such as silicon carbide and silicon nitride, are considered ideal for engine parts due to their high temperature resistance, low density, and low coefficient of thermal expansion.
Research shows that the use of the above types of materials can not only increase the operating temperature of the engine, but also significantly reduce the weight of the engine, thereby improving work efficiency and obtaining a greater thrust-to-weight ratio. In addition, in order to simplify the overall structure of the engine and further reduce weight and increase thrust, aero-engines generally use lightweight and integrated parts, such as integral blisks and blade rings. The ceramic parts additive manufacturing technology department does not require molds, rapidly manufactures complex structural ceramic parts, and has a high degree of flexibility and strain capacity, so that industrial designers are no longer constrained by traditional ceramic manufacturing processes and manufacturing resources.
②Structure-function integrated ceramic parts
Structure-function integrated parts refer to new types of parts formed by organically integrating the load-bearing structure and functional structure in the traditional manufacturing mode. Take the radome as an example. As a structural-functional component, the radome is not only an important component of the warhead structure of a guided weapon, but also protects the aircraft from normal operation of communication, telemetry, guidance, and detonation systems under high temperature and corrosive environmental conditions. Therefore, it is necessary to carefully select the materials used and design the optimized structure.
At present, ceramic materials have been widely used in the manufacture of radomes. For example, silicon nitride is not only an excellent high-temperature structural material, but also a new type of functional material. It is one of the existing ceramic materials with the best comprehensive performance. Known as the most promising radome material. The radome material mostly adopts the sandwich structure, the outer layer is thinner and denser to ensure the resistance to rain erosion and ablation, and the thicker core layer with high porosity provides low dielectric constant and reliable mechanical properties, taking into account the mechanical properties and dielectric properties. At the same time of electrical performance, it can achieve high wave transmittance in a wide frequency band in the microwave or millimeter waveband. However, the sandwich mechanism is difficult to directly form through traditional processes. As a technology for directly manufacturing parts driven by 3D data, additive manufacturing has a high degree of geometric independence and can provide a new technological approach for the manufacture of structure-function integrated advanced ceramic parts (radomes, etc.) in the aerospace field.
③ Heterogeneous material functionally graded ceramic-based parts
Heterogeneous material functionally graded parts refer to parts composed of two or more materials, and the material composition and microstructure in the parts transition through a certain gradient. During the development of modern aircraft, different parts of the same component are often required to serve in different environments, that is, different parts of the same component are required to have different performances. For example, when an aircraft is flying at ultra-high speed in the atmosphere, the surface temperature of its head can reach 2100 ℃, so high temperature resistant ceramic materials must be used, while the subsurface layer with lower temperature should use metal materials with better strength and toughness. This requires controlling the composition and microstructure of the material of the aircraft head to change continuously along the thickness direction, so that its heat resistance and mechanical strength also gradually change along the thickness direction, thereby enhancing the reliability of the aircraft's operation. The additive manufacturing technology of ceramic parts can provide an effective solution to realize the structure and performance of the above-mentioned parts.
2. Problems that need to be solved urgently:
Although the additive manufacturing technology of ceramic parts has made great progress, there are still many problems to be solved in the future if the technology is to be further applied to the aerospace field.
①The problem that raw materials are difficult to meet the demand
The right raw material is the basis for additive manufacturing of ceramic parts. However, the ceramic raw materials used in the current additive manufacturing technology have the problems of few varieties, low quality and high preparation cost, which are difficult to meet the needs of additive manufacturing of ceramic parts. There are many reasons for this problem, such as insufficient research on raw materials for additive manufacturing of ceramic parts; insufficient optimization of raw material production processes by manufacturers, and low production efficiency. Therefore, improvements can be made in the future from the following aspects:
(1) According to different additive manufacturing technologies of ceramic parts, expand the research scope of its raw materials, and develop new and practical high-performance raw materials, such as ceramic pastes that can be used for photo-curing molding;
(2) In-depth study of the properties of existing raw materials such as powder characteristics (such as particle morphology, particle size and distribution, thermal conductivity, etc.), fuse characteristics (such as solid phase content, bonding strength and rheological properties, etc.), flakes The influence of properties (such as flexibility, strength and stackability) and slurry properties (such as slurry viscosity, light absorption, etc.) on the performance of additively manufactured ceramic parts;
(3) Optimize the preparation process of ceramic raw materials from the source of production, reduce the cost of raw materials, and improve the quality of raw materials.
②The problem of lack of systematic and in-depth research on the process
The additive manufacturing process of ceramic parts directly affects the macro and micro structure, performance, production cycle and cost of the product. At present, there are still the following problems in the additive manufacturing process of ceramic parts: the process technology is not stable enough, and the technology maturity is relatively low, resulting in poor consistency and low repeatability of product structure and performance; complicated post-processing procedures, such as infiltration, isostatic pressing It prolongs the manufacturing cycle of the product and increases the production cost. The existence of these problems restricts the popularization and application of additive manufacturing technology of ceramic parts in the aerospace field. Therefore, the following aspects need to be improved in the future:
(1) While focusing on solving the basic scientific problems of additive manufacturing of ceramic parts, strengthen the research and development of technologies and processes, master the general laws of additive technology for ceramic parts, establish a process database of different materials and components, and solve the consistency of product structure and performance. Sexual and repetitive problems;
(2) In view of the shortcomings of the existing ceramic parts additive manufacturing technology (such as the need to introduce a large number of binders, long production cycle, etc.), explore new post-processing processes or develop new direct additive manufacturing technologies to achieve high-performance ceramic parts. Low cost, fast manufacturing.
③The performance of ceramic parts still needs to be optimized
The inherent brittleness of ceramic parts makes them have problems such as high defect sensitivity, low toughness and poor reliability, which seriously restricts the popularization and application of additively manufactured ceramic parts in the aerospace field. Therefore, future research directions will mainly focus on the following aspects:
(1) Realize the innovative application of traditional toughening methods such as whisker, fiber and particle reinforcement and toughening in the additive manufacturing technology of ceramic parts;
(2) Using the advantages of additive manufacturing technology such as high flexibility and strain capacity, based on the optimized structure, additive manufacturing bionic laminated structure and gradient composite materials, etc.;
(3) Improve the evaluation methods for the reliability of ceramic parts, clarify the performance and life prediction methods of ceramic parts, and promote the development of non-destructive testing technology and performance characterization methods for additively manufactured ceramic parts.
④The talent reserve needs to be paid attention to, and the industry standard needs to be formulated
As a new type of advanced manufacturing technology for ceramic parts, if it is to be widely used in the aerospace field, in addition to solving the above problems, it is necessary to carry out in-depth research on equipment, software, standardization, etc. and strengthen professional talents 's cultivation. For example, research and develop multi-material additive manufacturing equipment, improve the performance of equipment (such as forming accuracy, forming efficiency and stability, etc.), reduce the price of additive manufacturing equipment, etc.; develop additive manufacturing software for material-structure-performance integration , to support multi-material, multi-structure, and multi-process composite manufacturing; accelerate the formulation of standards in the field of additive manufacturing of ceramic parts; promote the training of professionals in additive manufacturing of ceramic parts, etc.