Advancing metal powder production with computer modeling
Dennis Thuy-Petrov defended his PhD thesis at the Department of Mechanical Engineering on March 2.
The rise of 3D-printing technology offers many opportunities for metal production, such as the fast manufacturing of objects with complex designs. In addition, metal 3D-printing can contribute to more sustainable production by enabling reduced waste streams and the recycling of waste into new products. Metal 3D-printing often relies on the use of metal powders, which are melted together layer by layer to create the final object. The properties of this powder are crucial to the quality of the printed product. Therefore, it is important to understand in detail how these powders are produced. In his research, Dennis Thuy-Petrov aims to better understand the atomization of liquid metals by using computer models, so that this process can be optimized to produce suitable metal powders for 3D-printing.
In the atomization of liquid metals, very fine droplets of molten metal are formed, typically tens of micrometers in size. These droplets rapidly cool and solidify, resulting in a fine powder with excellent properties for 3D鈥憄rinting. However, controlling this process remains difficult, which leads to extra production steps and a lack of flexibility. The high temperature of the molten metal makes it challenging to study the process experimentally. Moreover, gas jets with a very high pressure and velocity are needed to break up the liquid metal into small droplets, creating a complex process that takes place in a very short time span. Because of these challenges, computer modeling offers an attractive way to study the atomization process in detail.
Examining the properties of liquid metals
Dennis Thuy鈥慞etrov presents a combination of computational methods to reliably predict the atomization of liquid metals. These models can, for example, predict the size of the powder particles, a critical parameter for 3D鈥憄rinting. The computer models are specifically developed for the unique properties of liquid metals, which often cause difficulties in existing droplet鈥慴reakup models. A detailed simulation can predict the exact deformation of the liquid metal surface near the nozzle tip during atomization. This provides valuable insights into the interaction between the gas flow and the liquid metal at the start of the process, and how this interaction leads to the formation of droplets. The models also help clarify the role of solidification in the overall atomization process.
Metal powders for the future
Thuy-Petrov鈥檚 research shows that the breakup of the liquid metal ends before the solidification starts. Therefore, it is unlikely that the solidification has an influence on the particle size of the powder. Although the models require a significant amount of computing power, the results help to develop simpler models of the process, which can be applied in an industrial context. With these models, a more flexible production of high-quality metal powders for 3D-printing can be achieved.
Title of PhD thesis: . Supervisors: Dr. Giulia Finotello, Prof. Niels Deen and Dr. Joris Remmers.