Powder-Based Materials Development
Resublimation of Mg during powder metallurgical processing. Photo: HZG
The department Powder-based Materials Development develops alloys on basis of magnesium and titanium, respectively. They are optimized in view of advanced powder technologies and possess tailored properties with respect to the very application. As technologies mainly sintering-based techniques like Metal Injection Moulding and 3D-printing processes utilizing filaments or granules are applied. The goal of combining materials development and special manufacturing technology is providing a tool for the fabrication of components optimized in properties as well as in geometrical functionality. In the frame of own biomaterials development mostly test specimens and implant prototypes are produced.
Protype of implantable screw made by powder techniques. Photo: HZG
Materials development without manufacturing test specimens and functional prototypes is impossible and even pointless if the goal is to bring components into the application. At the Institute of Metallic Biomaterials, these components are basically operational medical implants that require reproducible and reliable production. The type of manufacturing technique substantially determines the properties of the implant. The mechanical properties can differ significantlyif the same alloy is shaped to the desired geometry by means of different technologies, e.g. casting, forging, or additive manufacturing processes like Selective Laser Melting. The material and the manufacturing technique form a unit that gives the implant its specific properties. In the case of bio-degradable magnesium alloys, in particular, the production process can have an influence on the degradation of the implant. In consequence, the equality of test specimens and later the finished components has to be taken into account during manufacturing.
Implantable screws for spine fracture treatment. MIM made of TiAl6Nb7 powder (Design: Tricumed Medizintechnik GmbH) .
The department Powder-Based Materials Development therefore focusses on utilizing fine metal powders as base materials that are shaped by different techniques and finally sintered to a dense, solid component. Since it is the sintering process (known as firing in pottery making) which determines the properties, there is a huge variety in the selection of the shaping technology without changing these final properties. For instance, an injection moulding process such as that applied in the production of plastic products can be used or a 3D-printing process with filaments, as is commonly utilized in private 3D-printers. Depending on the geometry - whether e.g. specimens for mechanical or biological tests or an implant prototype are to be manufactured - the optimal shaping process can be selected in each case. Due to an identical sintering process, all these components have comparable properties despite their different shaping.
As sintering determines the materials properties, this process is the focus of our research activities. Magnesium alloy powders for degradable implants as well as titanium alloy powders for permanent implants and for technical applications are processed. Topics of research include the optimisation of the mechanical or degradation properties, the understanding of impurities that may be incorporated during processing and the physical process of the sintering itself. At this point, the work is supported by the development of sintering modelling. The research subjects range from fundamental metal physical research to purely technical processing challenges.
The department has access to a complete manufacturing chain for sintered products. Powder handling is done under inert gas condition inside of glove boxes. There are several options for blending powders with polymers (binders), as is necessary for some manufacturing techniques. Sintering furnaces are exclusively used for the processing of magnesium and titanium materials, respectively. In addition, diverse possibilities for analyses are available, e.g. a sintering dilatometer.
The long-term experience of the department members as well as the technical equipment are often interesting for industry. We look forward to collaborations. Contact us.