Mechanical properties of melt-grown Al2O3-ZrO2(Y2O3) eutectics with different microstructure
Mechanical properties of melt-grown Al2O3-ZrO2(Y2O3) eutectics with different microstructure
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DOI：
10.1016/j.jeurceramsoc.2005.01.004
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发表时间：
2005
影响因子：
5.7
通讯作者：
J. Pastor;J. Llorca;P. Poza;I. Francisco;R. I. Merino;J. Peña
中科院分区：
文献类型：
--
作者：
J. Pastor;J. Llorca;P. Poza;I. Francisco;R. I. Merino;J. Peña
研究了Al_2O_3-ZrO_2（Y_2O_3）共晶氧化物陶瓷的显微结构对其力学性能的影响。随着生长速率的增加，获得了具有三种不同微观结构的激光加热浮区法处理的棒：在Al 2 O3基质内均匀分散的不规则ZrO 2 laminates，具有包含分散的亚微米ZrO 2 laminates或由厚的菌落间区域包围的棒的核心的菌落，以及由非常细的ZrO 2 laminates的分散体形成并由薄的细胞间边界分隔的细长细胞。由均匀分散的ZrO_2层组成的共晶的平均弯曲强度（接近1.6GPa）是突出的，并且当整个样品的微观结构均匀时，它们也呈现出优异的Weibull模量（12.9）。带状不影响平均强度，但降低了威布尔模量。在一般情况下，弯曲强度降低的主要形态特征的微结构（菌落或细胞直径）的大小增加。胞间边界的厚度随着Y2 O3含量的增加而增加，并且在临界值以上，通过激活基于集中在胞间边界处的孔隙和缩孔的聚结的新的失效机制而显著降低强度。
The effect of the microstructure on the mechanical properties of Al2O3–ZrO2(Y2O3) eutectic ceramic oxides was studied. Rods processed by the laser-heated floating zone method with three different microstructures were obtained as the growth rate increased: a homogeneous dispersion of irregular ZrO2lamellae within the Al2O3matrix, colonies with a core containing a dispersion of submicron ZrO2lamellae or rods surrounded by a thick intercolony region, and elongated cells formed by a dispersion of very fine ZrO2lamellae and separated by thin intercellular boundaries. The average flexure strength (close to 1.6GPa) of the eutectics made up of a homogeneous dispersion of ZrO2lamellae was outstanding, and they also presented an excellent Weibull modulus (12.9) when the microstructure was homogeneous throughout the sample. Banding did not affect the average strength but degraded the Weibull modulus. In general, the flexure strength decreased as the size of the main morphological features of the microstructure (colony or cell diameter) increased. The thickness of the intercellular boundaries increased with the Y2O3content and, above a critical value, reduced dramatically the strength by activating a new failure mechanism based on the coalescence of the pores and shrinkage cavities concentrated at the intercellular boundaries.