• 3D Printing
  • The first 3D printed superconducting microwave resonator came out

Scientists have long focused on the mechanical properties of 3D printed materials, and now they want to do some tricks on electrical properties. Daniel Creedon of the University of Melbourne in Australia and several other researchers designed, printed and tested the world's first 3D printed superconducting microwave cavity. Scientists say they paved the way for mass production of cheaper and better quality superconducting parts. 3D printing of metal parts will revolutionize many industries. For example, aircraft carriers no longer need to carry turbine parts, weapon accessories and accessories equipped with fighters, each of which can be printed on the aircraft carrier. Many people are concerned that the mechanical properties of 3D printed parts are not as good as those produced by conventional processes, especially those that require working in harsh environments like jet engine components. Materials scientists have put a lot of effort into studying the mechanical properties of 3D printed parts. 3D printing technology is currently used to produce medical custom artificial bone tissue, jet engine bearings and prototypes for the automotive industry. The mechanical properties of 3D printed components are a hot topic of research, however, the electrical characteristics of the components are currently insufficiently studied. Daniel Creedon of the University of Melbourne in Australia and several other researchers designed, printed and tested the world's first 3D printed superconducting microwave cavity. They said they paved the way for mass production of cheaper and better quality superconducting originals. At present, many scientific instruments serving the frontier need to use a superconducting microwave cavity as a core component, which can store microwave energy in a resonant manner. In engineering, the energy loss of the microwave cavity is required to be as small as possible. The microwave cavity is the basic device in the field of microwave engineering. In the mid-1930s, microwave resonators began to sprout as part of radar technology. Although Japan and Germany were slightly ahead at first, in 1940, the United Kingdom invented a multi-cavity magnetron based on a microwave cavity, revolutionizing the performance of the radar, and the physical mechanism of multi-cavity magnetron operation is even unclear. During World War II, multi-cavity magnetrons ensured the decisive advantage of the Allied radar performance. Today, microwave resonators serve many technical fields: for example: accelerating charged particles in particle accelerators; detecting vibration with ultra-high sensitivity; ensuring the stability of the clock frequency of the atomic clock output; measuring the wavelength of microwaves; of course, serving thousands of thousands of Household microwave oven. In the cavity, the microwaves contact the electrons of the material on the surface of the cavity, so the resistance of the cavity material directly determines the performance of the microwave cavity. The ideal resistance of the cavity material is zero, ie superconducting. The cost of manufacturing a superconducting microwave cavity is high. 3D printing is expected to significantly reduce costs and increase production speed - but will 3D printing destroy the superconducting properties of materials? No one knows before Critton. To investigate the effects of 3D printing on the superconducting properties of materials, the Clerton team printed two resonant cavities with complex internal walls: they selectively melted aluminum powder to create a specific shape, and then continued to melt the aluminum powder, allowing the molten metal to adhere and Formed on the previously generated blank, so this is done until completion. This process is fast and cheap, but there are several potential problems. First, the surface of the 3D printed cavity is rough. Second, the aluminum powder used for 3D printing is not the same as the standard industrial aluminum powder Al-6061. Among the 3D printed aluminum powders, 12% of the silicon powder is used, while in the standard industrial aluminum powder, the silicon powder only accounts for 0.8% of the mass. The 3D printed aluminum powder contains 0.118% iron and 0.003% copper, while the industrial aluminum powder contains 0.7% iron, 0.15% copper, and 1.2% magnesium. No one knows before that the surface roughness and the compositional differences between 3D aluminum powder and industrial aluminum powder will lead to any results. The Clayton team is determined to answer this question. To their surprise, the difference in material composition did not affect the superconducting properties of the final 3D printed microwave cavity. According to the Clayton team, the cavity entered the superconducting state at minus 271.8 ° C, in line with theoretical expectations, and the electrical characteristics were highly similar to those made with Al-6061 industrial aluminum powder. “The performance of the 3D printed microwave resonator is completely comparable to that of the Al-6061 industrial aluminum powder, and the increase in surface roughness of the cavity caused by 3D printing does not affect the final performance.” In addition, they polished one of the 3D printing cavities. The inner wall was added to the chamber at 500 ° C and then naturally cooled to room temperature. This process causes silicon atoms as impurities to be extruded into the material structure. “The 4 hour annealing treatment at 500 °C successfully eliminated the silicon atoms as impurities, and the Q value of the cavity (the lower the microwave energy loss, the higher the Q value) was doubled.” The study has significant potential follow-up studies. value. One possible research direction is to use purer aluminum powder in 3D printing, which the Critton team said should make a higher quality cavity. The other direction is to create a cavity that cannot be produced by conventional manufacturing methods, and to obtain performance that was previously unachievable in engineering. The study opened up a new era in the production of superconducting microwave devices using 3D printing technology.