Fabrication and Characterization of High-Purity Alumina Ceramics Doped with Zirconia via Laser Direct Deposition

Abstract

Additive manufacturing of ceramics via laser direct deposition is particularly challenging owing to high thermal gradients and subsequently high tendency for thermally induced cracking. Therefore, it is necessary to have an improved understanding of the effects of processing conditions and material compositions on the quality of deposited ceramic parts. In this article, thin wall structures of high-purity ceramics were fabricated with commercially available alumina powder. The effects of zirconia dopants, varying from 0 wt.% to 10 wt.%, were studied. The microstructure and compositions of the manufactured specimens were characterized using scanning electron microscopy and energy-dispersive x-ray spectroscopy to study grain size, orientation and distribution. Grain size distribution varied within the deposited ceramic parts because of the non-uniform temperature distribution during printing. The zirconia dopant was found to mainly accumulate within grain boundaries. An increasingly finer microstructure was observed with increased zirconia doping materials in the printed samples.