Strength of additive manufactured alumina

The strength of 3D-printed alumina parts fabricated using the Lithography-based Ceramic Manufacturing (LCM) technology is investigated. The influence of the sintering parameters, printing direction, surface condition (i.e. machined or as-printed), and/or geometry on the strength distribution is studied under uniaxial and biaxial bending tests. Weibull parameters, i.e. characteristic strength and Weibull modulus, are determined and compared between the different samples. Experimental findings show that samples sintered at higher temperatures yield higher Weibull modulus, associated with a more homogeneous microstructure. Fractographic analyses reveal the influence of surface finish (as-printed or machined) on strength and show the importance of reporting testing configuration along with printing direction to assess the mechanical response of 3D-printed parts. Based on these results, manufacturing recommendations are given which shall advance the progress in optimization of alumina ceramics fabricated using the LCM technology.