Thermal properties for Al2O3-based melt-grown ceramics prepared by laser-directed energy deposition

Laser-directed energy deposition (LDED) has significant potential for the high-quality fabrication of complex structured ceramic components for high-temperature applications. However, a lack of understanding regarding the thermal properties limits the application of this technology in the preparation of melt-grown ceramics (MGCs). Herein, the thermal properties of Al₂O₃/trace mullite MGCs obtained using LDED and subsequent heat treatment are investigated, including thermal shock resistance and high-temperature strength. The findings demonstrate that the materials are vulnerable to thermal shock with cracking occurring at a temperature difference (ΔT) of 300 ℃. As the ΔT increases, the residual strength declines significantly due to the increased internal defects and thermal stresses in the samples. The high-temperature flexural strength decreases gradually with rising temperatures, reaching a value of 247.23 ± 39.26 MPa at 1000 ℃, demonstrating a retention rate of 47.17%. This study provides a valuable reference for the practical high-temperature application of LDEDed Al₂O₃-based MGCs.