Crack-reduced laser powder bed fused oxide ceramic parts by in-situ synthesis of negative thermal expansion phases

Both in industry and research, laser powder bed fusion is increasingly adopted for applications commonly involving metals and polymers. However, the application to other materials, specifically oxide ceramics, faces challenges for industrial implementations due to its unique properties, such as low thermal shock resistance, high brittleness and a low light absorptance level in the near-infrared range. This study provides a solution to increase powder absorptance at a wavelength of 1070 nm while also reducing cracking during laser processing of oxide ceramic parts by in-situ formation of the negative thermal expansion phases ZrW2O8 and Al2W3O12. The composition to achieve the lowest coefficient of thermal expansion according to the Turner model displayed the least amount of cracks in the laser-processed parts. Laser-manufactured parts using powders containing 50 vol% of ZrO2/WO3 granules showed a compressive strength of 499 MPa and a Young's modulus of 100 GPa.