Dependence of Mechanical Properties on Sintered Microstructure of High Purity Alumina Made by High-speed Centrifugal Compaction Process
Dependence of Mechanical Properties on Sintered Microstructure of High Purity Alumina Made by High-speed Centrifugal Compaction Process
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高速离心压实工艺制备的高纯氧化铝的机械性能对烧结微观结构的依赖性
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发表时间：
1999
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影响因子：
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通讯作者：
H. Kuroki
中科院分区：
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作者：
Hiroyuki Y. Suzuki;K. Shinozaki;S. Tashima;H. Kuroki
以密度和平均晶粒尺寸为微观特征，研究了微观结构对高性能氧化铝力学性能的影响。将纯度为99.99%且平均粒径为0.22 μ m的氧化铝粉末分散在25质量%的离子交换水中，施加10，000 - 20，000 g的离心力压制3 ks，在1423-1773K、0~172.8ks的空气气氛中烧结。结果表明，随着烧结过程中显微组织的发展，强度和硬度分别出现一个峰值，这些峰出现在相对密度约为99%、晶粒尺寸约为1 μ m的同一试样上。对于密度小于99%的试样，抗弯强度和硬度随密度的减小而减小，而对于密度大于99%的试样，抗弯强度和硬度随晶粒尺寸的增大而减小.这些方程提供了在粒度/相对密度图上代表具有相同强度或硬度的微结构的等高线。将由不同试样的晶粒尺寸和密度得到的轨迹线叠加在图上，该轨迹线与其中一条轮廓线的接触点代表了力学性能的最佳晶粒尺寸和相对密度组合。
Influence of microstructures on mechanical properties of high performance alumina is investigated focusing on density and mean grain size as microstructure characteristics. An alumina powder with a purity of 99.99 % and mean grain size of 0.22μm is dispersed in 25 mass % of ion-exchanged water, compacted applying a centrifugal force of 10, 000-20, 000 g for 3 ks, and sintered at 1423-1773 K for 0-172.8 ks in air.It is shown that strength and hardness have one peak value respectively as microstructure develops during sintering, and those peaks appear on the same specimen with a relative density of about 99 % and grain size of about 1μm. For the specimens with density lower than 99 %, the strength and hardness decrease as density decrease, whereas for the ones with density higher than 99 %, those values decrease as grain size increase.Furthermore, two empirical equations, which show the dependence of bending strength and hardness on both porosity and grain size, are derived by multivariate analysis. These equations provide contour lines which represent microstructures having the same strength or hardness on the grain-size/relative-density diagram. Superposing a trajectory line derived from grain size and density of various specimens on the diagram, the point where this trajectory and one of contour lines contact represents the best couple of grain size and relative density for the mechanical properties.