Crack-healing, a novel approach for a laser-based powder bed fusion of high-performance ceramic oxides

Laser-based powder bed fusion (PBF-LB) of ceramic materials have not been developed sufficiently. The process-induced crack formation is the key challenge of the associated additive manufacturing method, which prevents its successful industrial implementation. Therefore, we have adopted a strategy to accept crack formation as an inherent characteristic of the manufacturing process while enhancing the mechanical properties of the parts by repairing the cracks using a thermal post-processing. Crack healing was successfully demonstrated in the PBF-LB-manufactured alumina titanium carbide (TiC) composite parts after thermal treatment in the air at 900 °C. Crack healing is achieved through the phase transformation from TiC to TiO2 in the form of rutile. The built parts exhibited a mechanical strength up to two times higher than values demonstrated in the previous studies on alumina PBF-LB without preheating, achieving an average flexural strength value of 181 MPa and a maximum value of 232 MPa.