Holistic high-temperature assistance for laser directed energy deposition of Al2O3/ZrO2 eutectic ceramics: cracking behavior

Laser-directed energy deposition (LDED) has emerged as a primary technology for the direct additive manufacturing of melt-growth ceramics (MGCs). However, cracking during fabrication severely limits further development of this technology. This study investigated a new holistic high-temperature-assisted method for LDED to solve the cracking problem. This method mitigates the high temperature gradients caused by the low thermal conductivity of the material during fabrication, thereby suppressing crack formation. The LDED of Al₂O₃/ZrO₂ eutectic ceramics was performed at a holistic auxiliary temperature of up to 1 273 K, and the crack-suppressing effectiveness and mechanism were verified by combining numerical simulations and experiments. The results demonstrated that holistic high-temperature assistance significantly mitigated cracking in Al₂O₃/ZrO₂ eutectic ceramics fabricated via LDED. At an auxiliary temperature of 1 273 K, the stress level in the fabricated sample was reduced by an order of magnitude compared to that at room temperature. Consequently, the lengths and densities of the cracks in the fabricated samples decreased by 47.6% and 55.6%, respectively. This study confirmed that the holistic high-temperature-assisted LDED method could play an important role in the additive manufacturing of low-ductility materials.