Hypereutectic Al₂O₃/YAG/ZrO₂ in Situ Composite Prepared by Horizontal Laser Zone Melting

Al₂O₃/YAG/ZrO₂ eutectic in situ composite has now been considered as the new generation of high-temperature structural material due to its excellent performance even close to its melting point. In this work, hypereutectic Al₂O₃/YAG/ZrO₂ in situ composite is manufactured by the horizontal laser zone melting technique. The relationship between the solidification microstructure and the solidification parameters is studied. The minimum lamellar spacing is as finer as 0.20μm when the laser scanning rate is 800μm/s. Compared with eutectic Al₂O₃/YAG/ZrO₂, hypereutectic exhibits more regular and finer microstructure at the similar conditions. Meanwhile, it is found that the lamellar spacing remains almost as constant at a certain high solidification velocity. The maximum hardness and fracture toughness are 15.9GPa and 4.2MPa · m^1/2, respectively.