Solute-induced grain refinement for crack suppression in laser additive manufactured ceramics

Laser additive manufacturing (LAM) has the potential to revolutionize ceramic manufacturing field by enabling the rapid production of near-net-shaped parts, circumventing the arduous post-sintering processes typical in traditional methods. However, the inherent brittleness of ceramics and rapid cooling during LAM lead to significant cracking, hindering widespread application. To address this challenge, an innovative material design approach is proposed, drawing inspiration from grain refinement principles in metal casting. We demonstrate its efficacy in yttria-stabilized zirconia of commercially relevant by introducing growth restrictive solutes. Leveraging substantial undercoolings at the solid-liquid interface and solute-induced growth restriction, this manipulation reshapes the microstructure from coarse columnar grains to fine and equiaxed grains. The microstructural transformation yields a remarkable toughening effect, effectively countering crack formation in LAM-fabricated ceramics. Our findings hold promise for the design of other ceramic materials and provide a promising pathway to unlock the full potential of LAM for high-performance ceramic fabrications.