Light-Weight Structural Materials

Light-weight materials are of high importance for the transportation industry for reducing fuel consumption, green house gas emission, and improving the efficiency of energy converting systems. Besides commonly used materials like steel, aluminium and titanium alloys, novel alloys based on magnesium and on titanium aluminides are of special interest due to their promising property profiles for specific applications.

In future applications, selected magnesium based materials will be used in the power trains of automobiles as well as in structural components made from cast and wrought alloys. Therefore, a number of inherent problems of magnesium alloys have to be solved. Among these are their insufficient corrosion properties, especially when being in contact with other metallic materials, the limited formability of current magnesium wrought alloys, the poor high temperature properties of the most common cast alloys, and the low ductility of most magnesium materials. Similar problems exist for titanium aluminide (TiAl) alloys which actually are not fully developed and are only available from pilot scale processing. Here, reliability is another problem still to be solved.

To overcome these limitations, alloy development in the programme "Advanced Engineering Materials" aims to provide new magnesium cast alloys with improved high temperature behaviour, and new classes of wrought materials both for magnesium and TiAl based materials. For both classes of materials the processing routes also have to be optimised. The work on alloy development and process optimisation is complemented by computational methods and by the creation of tools for predicting the microstructures and properties in order to assess the process chains and the lifetimes of components. The major aim is to understand the interaction of alloying elements and microstructure and the influence of the processing on a specific manufacturing route on a scientific base. Also, economic recycling routes need to be developed to meet the demands of industry and legislature. Because of the poor corrosion behaviour of magnesium alloys, in addition to specific alloy development protective coatings are required that should preferentially offer self-healing capabilities. Furthermore, the manufacture of TiAl-components with complex geometries via metal injection moulding (MIM) shall be evaluated.

Also activities in the area of medical applications of magnesium based materials have been started. Here, the aim is to identify suitable alloy compositions and processing routes for using magnesium based materials as stents, implants and for tissue engineering.

One suitable processing route is the so called metal powder injection moulding (MIM) technique. Main topic of the developments is the processing of oxygen-sensible titanium and magnesium alloys and fabrication of precision components for machinery and medical applications.