Research and Development Trends and Problems of Advanced Copper Alloy Materials
Copper and copper alloys are a class of key materials with important applications. Due to its excellent thermal conductivity, electrical conductivity, ductility, corrosion resistance and other properties, copper is a necessary material in certain applications of aerospace, weapons and equipment. In the past two years, the manufacturing industry has clearly felt the growth in demand for copper alloys. New users are constantly developing copper alloy additive manufacturing applications. The materials have also shifted from early easy-to-form cast tin bronze to pure copper and various types of high-strength and high-conductivity copper. According to a research report, the global copper additive manufacturing market will grow at a compound annual growth rate of 51% from 2019 to 2027. Although there are still many process and material problems in copper alloy printing, it is foreseeable that copper will have a place in metal additive manufacturing. The application status of copper alloy materials at home and abroad. With the rapid progress of high-tech industries, new materials are developing in the direction of ultra-high performance, high purity, and high iteration. The integration, functionality, miniaturization, reliability, etc. of related products have been proposed. Higher requirements. As core conductor materials, advanced copper and copper alloys are widely used in lead frames of very large scale integrated circuits in the electronic information industry, electronic countermeasures, radars, high-power microwave tubes for national defense equipment, conductor materials for high pulse magnetic fields, overhead wires for high-speed rail transit, and large Power frequency modulation and speed regulation asynchronous traction motor guide bars and end rings, resistance welding electrodes, battery materials, charging pile elastic materials for new energy vehicles, continuous casting machine crystallizers and electric vacuum devices for the metallurgical industry, switch contact bridges and various components for electrical engineering Wires, etc. At present, many well-known foreign additive manufacturing manufacturers have included copper materials in their product catalogs. More representatively, EOS published data sheets for pure Cu and CuCrZr in 2020, and in 2021 launched AMCM (Additive Manufacturing Customized Machine) versions of the two types of materials, a subsidiary of EOS. SLM Solutions has successively launched CuSn10 and CuCrZr product data. In 2019, the company launched CuNi2SiCr products that combine strength and electrical and thermal conductivity. They can be used in the mold and electrical fields and have become a blockbuster product in additive manufacturing copper alloy materials. Material manufacturers TLS Technik, m4p, Sandvik, Makin and other companies have announced their own additive manufacturing copper alloy products. At present, copper and copper alloy materials for additive manufacturing are concentrated in pure Cu, CuSn10, CuCrZr and CuNi2SiCr. Although CuNiSn, CuCr, CuCrNb, CuAlFeNi and other materials also have related additive manufacturing research and applications, the degree of application is not as high as the first four categories of products. 1. Compared with copper alloys, the advantage of pure Cu is its electrical and thermal conductivity, because various copper alloys will inevitably lose electrical and thermal conductivity after adding elements to copper. Since pure copper has a low absorption rate at the conventional 1064nm wavelength, the so-called red light wavelength, and is difficult to achieve densification, pure Cu printing has always been a problem. The current solution is to use short-wavelength lasers, such as TRUMPF's 515nm green laser equipment, and the other is to increase the power, such as EOS's AMCM equipment equipped with a 1Kw laser for pure copper printing. No matter what type of equipment is used for printing, if you want to obtain pure copper parts with high density or high electrical and thermal conductivity, the raw material powder needs to maintain high purity while also having powder characteristics that make it easier to achieve densification, such as reasonable particle size distribution and flow. It has the characteristics of good durability and high bulk density. <img src="https://picx.zhimg.com/v2-20ef1508f6a95754be387cae405ccec0_720w.jpg?source=d16d100b" data-caption="" data-size="normal" data-rawwidth="484" data-rawheight=" 183" class="origin_image zh-lightbox-thumb" width="484" data-original="https://pica.zhimg.com/v2-20ef1508f6a95754be387cae405ccec0_720w.jpg?source=d16d100b">In terms of pure copper powder preparation , maintaining high purity of materials while maintaining high sphericity is the goal. 2. CuSn10 CuSn10 is a kind of cast tin bronze that is easy to form. Many models or crafts involving copper materials use CuSn10 material for printing. <img src="https://picx.zhimg.com/v2-dd0b61171bb8b2b161a3bea8792aec88_720w.jpg?source=d16d100b" data-caption="" data-size="normal" data-rawwidth="454" data-rawheight=" 171" class="origin_image zh-lightbox-thumb" width="454" data-original="https://pica.zhimg.com/v2-dd0b61171bb8b2b161a3bea8792aec88_720w.jpg?source=d16d100b">CuSn10 alloy has high strength and durability It has excellent wear and corrosion resistance and can be used to manufacture wear-resistant parts such as blades and gears. However, its electrical and thermal conductivity is not high, so CuSn10 is generally not used for electrical or thermal conductivity requirements. CuSn10 is a conventional product among current additive manufacturing copper alloy materials. 3. CuCrZr rocket engine is a typical application scenario of copper alloy. The material requirements for engine linings and related parts are extremely high. On the one hand, the combustion temperature in the combustion chamber is extremely high (more than 3000°C). On the other hand, high temperature, high pressure, and high-speed gas have strong erosion on the materials. CuCr alloy is a typical precipitation-strengthened copper alloy. The addition of Zr element can promote the precipitation of Cr phase and improve the distribution of precipitated phases. At the same time, the copper-zirconium compound formed by Zr and Cu can play the role of precipitation strengthening. Therefore, the mechanics of CuCrZr alloy It has excellent performance and can be used in the manufacture of rocket engine parts. In recent years, domestic aerospace units have carried out a lot of research and development work on the additive manufacturing of rocket engine thrust chamber parts, and CuCrZr is the current optional material. <img src="https://pic1.zhimg.com/v2-cdf9bb1e7e5f86cd0f3d4164e27bf539_720w.jpg?source=d16d100b" data-caption="" data-size="normal" data-rawwidth="468" data-rawheight=" 186" class="origin_image zh-lightbox-thumb" width="468" data-original="https://pic1.zhimg.com/v2-cdf9bb1e7e5f86cd0f3d4164e27bf539_720w.jpg?source=d16d100b">It is worth mentioning that the Rockets Copper alloy materials for engine parts are still being updated and iterated. CuZr, CuCr, CuAgZr, CuCrNb and other materials have been applied in research, especially GRcop-42 (Cu-4Cr-2Nb at %), it is expected to upgrade rocket engine combustion chamber materials to a new level. 4. CuNi2SiCrSLM Solutions launched CuNi2SiCr copper alloy material product in 2019. This material is a heat-treatable hardenable alloy with high strength and a balanced combination of electrical conductivity and thermal conductivity. At the same time, the alloy includes nickel and silicon components and has a high Corrosion resistance and wear resistance. CuNi2SiCr itself is not a new component. This material corresponds to the American standard C18000 alloy. SLM Solutions took the lead in using this material for additive manufacturing and carried out material identification and parameter verification work, adding an important member to the additive manufacturing copper alloy family. . The strength of CuNi2SiCr after heat treatment is significantly higher than that of CuCrZr and other materials. At the same time, it can maintain a certain thermal conductivity and electrical conductivity. It can already meet some mold manufacturing requirements and conductive parts requirements, so it will have important applications in the mold and electrical fields. R&D trends and problems faced by my country's advanced copper alloy materials (1) Technology R&D trends In recent years, my country's overall level of high-performance copper alloys and their preparation technology has made great progress, and the types of high-performance copper alloy products with independent intellectual property rights have continued to increase. , the installed level of copper alloy material processing is close to the international advanced level. The development trend of R&D and industrialization of advanced copper alloy materials presents the following characteristics. (1) From single performance requirements to multi-functional feature requirements. For example, copper-based materials with high thermal conductivity and high electromagnetic shielding properties should meet the demand for conductor materials in high-precision fields such as pulsed strong magnetic field systems and particle accelerated electromagnetic transmitters; high-speed railway power grid contact lines with a speed of 380 km/h In addition to high electrical conductivity, it should also have higher strength, wear resistance and fatigue resistance; copper alloys for very large scale integrated circuits are required to have high strength and high conductivity, heat resistance, bending resistance, easy etching and other characteristics. (2) Copper processing materials are developing in the direction of thin, thin, long and high precision. The demand for products such as ultra-fine wires, ultra-thin strips, thin-walled tubes, extra-long tubes, extra-long strips, threaded pipes, special-shaped tubes, special-shaped rods, special-shaped strips, etc. continues to increase. For example, the lead frame reflects the multi-pin and high-density , the development trend of ultra-thin and miniaturization. (3) High purification of copper. The copper content of industrial copper has been increased from 99.9% to 99.95%, and then to 99.99% or even higher, in order to maximize the electrical and thermal conductivity of the material. Ultra-pure copper, containing 99.999 9% copper, will minimize the impact of impurities on electrical and thermal conductivity. (4) Material composite. A single material strengthening method has limited potential, and the use of composite methods to further improve the comprehensive performance of copper materials has become a research hotspot. For example, adding second-phase particles, whiskers or fibers to copper alloys to compositely strengthen the copper matrix and develop new multifunctional copper-based composite materials is of great importance to the design theory of high-performance copper alloys and practical applications in high-tech fields. value. (2) Problems faced Although my country is the largest producer of copper alloy materials in the world, it is still not a strong country in copper alloy materials. my country still relies heavily on imports for high-performance copper alloys that are urgently needed in many high-tech fields such as aerospace, electronic information, marine engineering, and high-end equipment. There are many copper alloy material production companies, low industrial concentration, weak product competitiveness, and meager industry profits. , unable to support the development of high-tech industries. The main issues involved in the copper alloy materials industry are as follows. (1) There are few varieties and grades of high-performance copper alloy materials. The comprehensive performance of some high-performance copper alloys is generally lower than that of similar imported products. For example, the grades of Cu-Ni-Si and Cu-Cr-Zr lead frame strips independently developed and produced are extremely low. few. (2) The stable production capacity of large-sized and high-quality copper alloy products needs to be improved urgently. For example, breakthroughs in performance stability, surface quality, and comprehensive finished products of high-precision elastic copper alloy strip products are still needed. (3) The processing process of high-performance copper alloys causes large environmental pollution and serious waste of resources; the high-efficiency short-process preparation technology is not yet mature, and product quality and performance need to be improved. (4) The lack of independent manufacturing technology for some high-end production equipment limits the development of new products. For example, most high-precision foil production equipment relies on imports. (5) Some high-end copper alloy materials lack independent intellectual property rights and public research and development platforms, and the construction of databases in terms of material properties, production technology, standards and specifications lags behind. (6) The large-size homogenized preparation technology of ultra-high purity, ultra-low oxygen content oxygen-free copper still needs to be further improved, and the preparation technology of high-precision, large-diameter, long-life corrosion-resistant white copper needs to be further broken through. Finally, compared to products such as titanium, aluminum, and high-temperature alloys, additive manufacturing of copper and copper alloys is not yet mature. EOS has introduced a concept similar to Technology Readiness Level (TRL) for material products since 2019. Currently, two types of copper materials are marked as Level 3, which is a verification level, while products such as IN718 and AlSi10Mg are generally Level 7-9. At this stage, additive manufacturing has gradually shifted from model verification to product manufacturing. Additive manufacturing materials will enter the stage of selecting or designing materials based on applications. The updated iteration of copper and copper alloy materials is more obvious. It is foreseeable that with the continuous advancement of processes and materials, the additive manufacturing application of copper materials will be elevated to a new level. (Material owner online)
