Direct powder bed selective laser processing of dense alumina-toughened zirconia parts

Alumina-toughened zirconia (ATZ) objects were manufactured by direct powder bed selective laser processing (PBSLP) with commercially available Prox200 (3D Systems) machine equipped with a Nd:YAG laser. 0.75wt.% graphite powder was mixed with ATZ powder to increase the laser absorbency from 2 to 60%. A combination between lasing speed and laser power was optimized to manufacture dense and geometrically accurate ATZ parts. The SEM observation of the vertical cross-section showed that an adequate laser–matter interaction was achieved by exposing consolidated microstructure and merged successive layers. Potential changes in the crystallographic of the ATZ powder structure before and after the laser processing were tracked by XRD analyses. Desired tetragonal-phase zirconia was conserved in the final objects, and absorbance enhancer graphite did not cause any phase transformation. Consequently, simple and complex shaped, highly consolidated, geometrically accurate and reproducible dense ATZ objects with high relative density around 96.7% were manufactured.