Additive manufacturing of ceramics and ceramic composites via robocasting

Abstract

In the last two decades additive manufacturing (AM) has emerged as a highly important and influential technology. A large range of approaches to AM have been developed which give rise to hundreds of distinct techniques. Many of these are specific to one material system, and only a handful have been successful at producing ceramic parts. Robocasting is one such technique, having been used to produce complex ceramic parts with reasonable mechanical properties. In this thesis robocasting is investigated further, firstly by characterising the rheology of the robocasting paste, and then by measuring the strength and reliability of ceramic parts produced by robocasting. The critical defects associated with the process are identified, and efforts have been made to eliminate them. Furthermore, it was possible to produce a new class of ceramic composites consisting of alumina platelets aligned by the shear forces that arise during printing. These platelets themselves and the composites were extensively characterised. A new in-situ double cantilever test was developed in order to study the fracture behaviour of the composites. Lastly, the principle of using the printing process to align platelets was applied to fibres in order to create printed fibre reinforced ceramic matrix composites, and printed carbon fibre reinforced epoxy.