Global market leader in the metal industry promotes material research at Saarland University
The raw material niobium is subject to strong global demand, especially in the steel industry. For example, it’s used in pipelines because of its ability to prevent steel from becoming brittle, even at subzero temperatures. When used in vehicles, it ensures steel frames remain stiff but at the same time malleable. The metal ore is primarily extracted in Brazil and Canada from volcanic rock. The international market leader for this important raw material is the Brazilian company CBMM. The firm has agreed to sponsor a material science researcher at the University of Saarland as part of the first phase of a project at the Material Engineering Center Saarland (MECS, a Steinbeis Research Center). The scientists aim to use atom probe tomography to investigate how niobium atoms enter the nanostructures of steel and change its material properties.
Niobium is used in comparatively small quantities in steel production. “Only around one in every 10,000 atoms in steel is niobium. That’s why it’s all the more surprising that it’s so effective in such minute concentrations. It makes steel tougher in such a way that it becomes malleable without compromising stability. But niobium also prevents steel from becoming brittle at subzero temperatures or suddenly shattering like porcelain,” explains Frank Mücklich, professor for functional materials at the University of Saarland and director of the Steinbeis Research Center Material Engineering Center Saarland. This is particularly important for oil and gas pipelines laid in Arctic temperatures. Niobium is also added to steel in the automotive industry because it’s the only way to ensure that steel parts can absorb sufficient amounts of energy in car bodies while at the same time shielding the passenger cell if there’s an accident.
Frank Mücklich’s research team is specialized in the spatial analysis of inner material structures based on a variety of scales. To do this, they use a number of different 3D methods and over the years the scientists have successfully refined their techniques to ensure they are closely matched to one another. “We use high-resolution electron microscopes, plus nano and atom probe tomography. The 3D data and 2D image sequences these provide are then entered into a computer to create an exact spatial image, right down to the individual atom,” says Frank Mücklich. Using 3D analysis allows the researchers to observe all kinds of changes going on within the inner structures of steel, and this can be quantified to examine which mechanisms influence which required properties. “Our aim is to understand the inner structures of steel so precisely that we can see how niobium atoms enter inner microstructures during the production process. That’s the only way to be able to ‘design’ suitable internal structures for steel to match certain applications. Then we would know things like the most effective way for us to get niobium to deliver superior material properties, or how specifically using niobium would enable us to reduce the need for other expensive alloy elements – or even avoid expensive parts of certain processes,” continues Mücklich.
Frank Mücklich and his colleagues presented their precise 3D analysis method to a small group of internationally renowned niobium researchers, following an invitation to a joint workshop on the university campus in Saarbrücken last year. One company, CBMM, now wants to forge ahead with niobium research and is backing the Saarbrücken material researchers through a project called Niobium in Steel. The first phase of the project will take the scientists three years. The research is not just about understanding the mechanisms going on within steel in more detail, it is also hoped that it will help control production processes more effectively.