Design of Semi-Solid Forming Tools for Producing Metal-Ceramic Interpenetrating Phase Composites

摘要

Compared to more common particle or fibre reinforced composite materials, Interpenetrating Phase Composites (IPC) show a continuous volume structure of not only the matrix component but also the reinforcement. Thus, IPC having a metal matrix and a ceramic reinforcement reveal enhanced properties, such as a high creep resistance at high temperature levels and a high wear resistance while maintaining high fracture toughness. Hence, these composites may find application in brake elements, cylinder liners or electrical switch elements. Basically, properties of such metal-ceramic IPC are determined by the raw material characteristics of the metal and the ceramic component, but also the manufacturing process considerably influences the achievable composite quality. This is because specification and design of the manufacturing process immediately affect the structural characteristics of the composite, such as damage of the ceramic component, residual porosity within the composites volume and interface reactions between the metal and ceramic component. In this context, one possibility of processing metal-ceramic IPC is the infiltration of ceramic open-pore bodies with a metal alloy in the semi-solid state. In this regard, the presented paper deals with the development of a semi-solid forming tool for producing metal-ceramic IPC having an aluminium alloy as metal component and an alumina open-pore body as ceramic component. For this purpose, two tool concepts were numerically investigated, one with an open die cavity and the other one with a closed die cavity. These initial numerical studies showed that the selected tool concept significantly influences pressure level and distribution within the cavity and thus affects the flow behaviour of the semi-solid metal alloy during infiltration. In order to substantiate these simulation results, metal-ceramic IPC were experimentally manufactured using both cavity types and by taking into account different temperatures of the aluminium alloy. The resulting structural composite characteristics were analysed and compared.