PICTURE: Tungsten component made by 3D printing using electron beam melting. (Photo: Markus Breig, KIT) View More
Photo credits: Markus Breig, KIT
At 3,422 degrees Celsius, tungsten has the highest melting point of all metals. This makes the material ideal for use at high temperatures in e.g. B. space rocket nozzles, heating elements of high-temperature furnaces or in the fusion reactor. However, the metal is very brittle and therefore difficult to process. Researchers at the Karlsruhe Institute of Technology (KIT) have developed an innovative approach to make this brittle material soft. For the processing of tungsten, they have defined new process parameters for melting electron beams.
Tungsten is a metal with very attractive properties: it is corrosion-resistant and as heavy as gold. In the form of tungsten carbide, it is as hard as diamond. And it has the highest melting point of all metals, 3,422 degrees Celsius. However, the metal is very brittle at room temperature. Due to its properties, tungsten is difficult to process using conventional methods. Processing is expensive and time-consuming. An alternative is 3D printing, which can be used to produce tungsten components that hardly need any post-processing. “We are currently working on the additive manufacturing of tungsten components using electron beam melting, or EBM for short,” says Dr. Steffen Antusch from the Institute for Applied Materials – Materials Science and Technology (IAM-WK) at KIT. The team managed to adapt the EBM process to Wolfram. After developing specific process parameters, 3D printing of tungsten components is now possible. “This metal can be used in many areas. Due to its special properties, it is ideally suited for high-temperature applications in energy and lighting technology, the aerospace industry and medical technology. It is indispensable in modern high-tech industry,” says Alexander Klein, IAM-WK.
Preheating enables brittle materials to be processed
EBM is an additive manufacturing method. Electrons accelerated under vacuum selectively melt metal powder, thus creating a 3D component in an additive manner, that is, layer by layer. The great advantage of this method is the energy source used, the electron beam. It is used to preheat the metal powder and backing plate before melting, which reduces deformation and internal stress. It is possible to process materials that break easily at room temperature and can be deformed at high temperature.
However, the materials used must be electrically conductive. The method is therefore not suitable for ceramic materials, as EBM is based on the principle of electrical charging.
Light titanium components for KA-RaceIng
EBM was originally developed to process titanium alloys and materials that require higher process temperatures. So far, lightweight titanium components have been manufactured with EBM for the KA RaceIng formula student project of the KIT.
As part of the research programs of the Helmholtz Association and EUROfusion, the European fusion program, the IAM-WK examines materials and processes for future high-temperature applications in the field of fusion energy or medical technology. (rli)
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Further information on the KIT Materials Center: https://www.kit.edu/topics/materials.php
Contact for this press release
Regina Link, press officer, phone: +49 721 608-41158, email: [email protected]
As a “Research University in the Helmholtz Association”, KIT creates and imparts knowledge for society and the environment. The aim is to make a significant contribution to the global challenges in the areas of energy, mobility and information. Around 9,600 employees work together in a wide range of disciplines in the natural, engineering, economics, and humanities and social sciences. KIT prepares its 23,300 students for responsible tasks in society, industry and science by offering research-based study programs. The innovation efforts of KIT build a bridge between important scientific findings and their application for the benefit of society, economic prosperity and the preservation of our natural basis of life. KIT is one of the German universities of excellence.
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