Additive manufacturing of high-strength alumina through a multi-material approach

This work demonstrates the use of additive manufacturing to design and fabricate alumina ceramics with strength as high as 1 ​GPa. A multi-material approach is employed by embedding alumina-zirconia layers between outer pure alumina layers with significant compressive residual stresses. Biaxial bending is performed both on the 3D printed multi-material and monolithic alumina parts. Results are analysed in the framework of Weibull statistics. A characteristic biaxial strength higher than 1 ​GPa is measured on the multilayers, compared to 650 ​MPa in monolithic alumina, the difference corresponding to the magnitude of compressive residual stresses due to the thermal mismatch between material regions during cooling from sintering. This is the first report of employing additive manufacturing to tailor the strength of alumina ceramics, taking advantage of the layer-by-layer printing process. Designing complex-shaped ceramic architectures with residual stresses through additive manufacturing opens a new path for fabrication of technical ceramics with tailored mechanical properties.