Oxidation is a tiresome issue in metal processing. Production in an oxygen-free environment could provide a remedy. The LZH is researching how this concept can be implemented in additive manufacturing and soldering.
Oxidation layers that form when metals come into contact with oxygen impair the processing and properties of the end products. The LZH is developing processes in which a protective gas consisting of argon with an addition of silane is used during production. This method results in an atmosphere that is virtually free of oxygen, comparable to the conditions of an extremely high vacuum (XHV). This innovative approach offers a cost-effective alternative to conventional vacuum techniques.
A sub-project of the LZH is dedicated to soldering without flux. Traditional fluxes, which are used to break up oxide layers, can be harmful to the environment and health. Instead, the LZH researchers use a pulsed laser beam source to break up the oxide layer, followed by a soldering process in a silane atmosphere. This oxygen-free environment prevents re-oxidation of the surface and enables effective bonding of the materials.
The research shows that it is possible to permanently remove the oxide layer on aluminum alloys and achieve good wetting with the solder material. The next steps include applying this process to the joining of aluminum with copper in order to explore the limits of the process.
In the field of additive manufacturing, the LZH is investigating the processing of metal powders in an oxygen-free atmosphere. By using a specially developed system for powder bed-based laser beam melting, the process for the titanium alloy Ti-6Al-4V could be optimized. The researchers expect that the absence of oxygen will lead to a more stable production process, less material spattering and improved component properties. Initial results confirm these assumptions, but the elimination of moisture in the atmosphere and in the powder is crucial for further process improvement.
This research work by the LZH clearly demonstrates the potential to significantly increase efficiency and quality in metal processing through innovative approaches in oxygen-free production.