Processing, microstructure and mechanical properties of directionally-solidified Al2O3–Y3Al5O12–ZrO2 ternary eutectics
Processing, microstructure and mechanical properties of directionally-solidified Al2O3–Y3Al5O12–ZrO2 ternary eutectics
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DOI：
10.1016/j.jeurceramsoc.2005.11.005
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发表时间：
2006
影响因子：
5.7
通讯作者：
J. Peña;M. Larsson;R. I. Merino;I. Francisco;V. Orera;J. Llorca;J. Pastor;A. Martin;J. Segurado-J.
中科院分区：
文献类型：
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作者：
J. Peña;M. Larsson;R. I. Merino;I. Francisco;V. Orera;J. Llorca;J. Pastor;A. Martin;J. Segurado-J.
采用激光加热浮区法，以 10 至 1000mm/h 的生长速率生长三元共晶成分（65mol% Al2O3、19mol% ZrO2、16mol% Y2O3）中直径为 1-2mm 的 Al2O3/Y3Al5O12/ZrO2 棒。在低生长速率下，棒材呈现出由相似尺寸的Al2O3(40%)和Y3Al5O12(42%)域的互穿网络形成的汉字微观结构，在Al2O3/Y3Al5O12界面处具有较小的立方Y2O3稳定的ZrO2(18%)域。通过压电谱测量了氧化铝相中 200MPa 的残余压应力，并通过自洽模拟验证了其热弹性起源。相间距和残余应力随着生长速率的增加而减小，这影响了硬度和断裂韧性。三元共晶棒细小且均匀的微观结构使其在环境温度下具有 2.3GPa 的出色弯曲强度，并在 1473K 时保持不变，然后在 1700K 时迅速下降至 1.2GPa。
Rods of 1–2mm diameter of Al2O3/Y3Al5O12/ZrO2in the ternary eutectic composition (65mol% Al2O3, 19mol% ZrO2, 16mol% Y2O3) were grown by the laser-heated floating-zone method at growth rates between 10 and 1000mm/h. At low growth rates the rods presented a Chinese script microstructure formed by an interpenetrating network of Al2O3(40%) and Y3Al5O12(42%) domains of similar size, with smaller cubic Y2O3-stabilized ZrO2(18%) domains at the Al2O3/Y3Al5O12interfaces. Compressive residual stresses of 200MPa were measured in the alumina phase by piezo-spectroscopy and their thermo-elastic origin was validated by self-consistent simulations. The phase spacing and the residual stresses decreased with increasing growth rate and this influenced the hardness and the fracture toughness. The fine and homogeneous microstructure of the ternary eutectic rods led to an outstanding flexure strength of 2.3GPa at ambient temperature, which was retained up to 1473K, and then decreased rapidly to 1.2GPa at 1700K.