Formation and suppression of cracks in ceramics prepared directly by laser additive manufacturing

Ceramic materials， with their high strength， high hardness， excellent high-temperature resistance， and superior corrosion resistance， have broad application prospects in fields such as machinery， electronics， aerospace， and biomedical engineering. However， traditional ceramic processing techniques are restricted by mold dependency and limited design freedom， making it difficult to meet the demand for efficient and rapid manufacturing of complex components. Laser additive manufacturing （LAM）， including laser powder bed fusion （LPBF） and laser directed energy deposition （LDED）， primarily achieves three-dimensional solid formation through layer-by-layer laser melting and stacking， providing a revolutionary solution for the rapid， customized manufacturing of complex-shaped ceramic components. However， the crack defects generated during the rapid solidification process in LAM severely constrain performance enhancement and engineering applications， becoming an urgent challenge and research hotspot in this field. This paper outlines the forming principles and the latest domestic and international progress of ceramic materials using LPBF and LDED technologies. It focuses on discussing the crack formation mechanisms， microstructural evolution， mechanical properties， and their influencing factors in direct laser additive manufacturing of ceramics. Additionally， it systematically summarizes strategies for suppressing cracks， such as forming preheating， process optimization， ultrasonic assistance， and microstructural control， along with their effects. Finally， it provides an outlook on the future development trends and core challenges of ceramic LAM technology， focusing on directions such as multi-physical field coupling simulations， material composition optimization， and multi-field assisted technologies， offering guidance for promoting the rapid development of ceramic laser additive manufacturing technology.