Submitted Abstract
The objective of this research project is the combination of standardized flow tests used in an industrial context with fundamental research in the field of rheology in order to understand and develop models describing the flow of hard metal granules. One basic flow model of granular solids through orifices has been described by a phenomenological approach, the so-called Beverloo law, where different properties of simple granules, e.g. glass beads were considered. Hence, the scientific models are not applicable for complex hard metal granules. In this work, a new experimental approach will be the use of a rotational and capillary rheometer to analyse the flow of hard metal granules. Using rotational and capillary rheology, it is expected to understand and describe flow-induced rearrangements of granules. Depending on the granules properties, it is expected to quantify differences in the ability to rearrange due to the number of contact areas between granules and varying inter-particle forces. A model, capable of predicting the flow as well as the packing fraction of well-characterized metal powders would have a massive impact on the ability to control the flow characteristics of the granules produced by the spray drying process. This optimisation would allow to improve the present die filling process and would increase the capability to produce more complex pressed parts as well as increased process and product quality.