Directionally solidified oxide eutectic ceramic (DSOEC) has been one of the focuses of ceramic materials because of its excellent mechanical properties and oxidation resistance at ultra-high temperature (above 1600 ℃). Al₂O₃/GdAlO₃/ZrO₂ ternary DSOEC was prepared with induction heating zone melting method, of which microstructure and mechanical properties’ involution with the growth rate was revealed. As the growth rate increased, the microstructure of Al₂O₃/GdAlO₃/ZrO₂ DSOEC became into a complex regular structure from an irregular network structure, and the eutectic spacing decreased continuously. Its fracture toughness increased first from 4.75 to 6.55 MPa m^1/2 and then decreased to 5.48 MPa m^1/2, while its hardness increased continuously from 12.20 to 15.56 GPa. The third component ZrO₂ made GdAlO₃ phase microstructure in the binary eutectic Al₂O₃/GdAlO₃ from a complex regular structure transformed into an irregular network one in the ternary Al₂O₃/GdAlO₃/ZrO₂ for the low growth rate, while from the regular layered microstructure to the regular triangular one in the ternary eutectic for the high growth rate, ZrO₂ phase also increased the eutectic spacing, improved the fracture toughness. The fracture toughness at room temperature (4.75–6.55 MPa m^1/2) of Al₂O₃/GdAlO₃/ZrO₂ ternary DSOEC was much higher than that of Al₂O₃/GdAlO₃ binary DSOEC (1.47–3.24 MPa m^1/2).

Graphical abstract

中文翻译：

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Al2O3/GdAlO3/ZrO2三元共晶陶瓷组织与性能随生长速率的演变

定向凝固氧化物共晶陶瓷(DSOEC)因其优异的力学性能和超高温(1600℃以上)抗氧化性能一直是陶瓷材料的研究热点之一。采用感应加热区熔法制备了Al ₂ O ₃ /GdAlO ₃ /ZrO ₂三元DSOEC，揭示了其显微组织和力学性能随生长速率的关系。随着生长速率的增加，Al ₂ O ₃ /GdAlO ₃ /ZrO ₂ DSOEC的微观结构由不规则网状结构转变为复杂的规则结构，共晶间距不断减小。其断裂韧度先从4.75 MPa m ^1/2增加到6.55 MPa m 1/2 ，然后下降到5.48 MPa m ^1/2，而硬度则从12.20 GPa持续增加到15.56 GPa 。第三组分ZrO ₂使二元共晶Al ₂ O ₃ /GdAlO _{3中的GdAlO 3}相显微组织从复杂的规则结构转变为三元Al ₂ O ₃ /GdAlO ₃ /ZrO ₂中的不规则网状结构，以实现低生长速率同时，三元共晶中ZrO _{2 相}的生长速度由规则的层状组织转变为规则的三角形组织，ZrO 2相也增大了共晶间距，提高了断裂韧性。Al ₂ O ₃ /GdAlO ₃ /ZrO ₂三元DSOEC的室温断裂韧性(4.75~6.55 MPa m ^1/2 )远高于Al ₂ O ₃ /GdAlO ₃二元DSOEC的室温断裂韧性(1.47~3.24 MPa m 1/2 )。^1/2）。

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