Innovtaive Solidification Processing for Advanced Materials. Phase Selection of the Al2O3-Y2O3 System Controlled by Nucleation.
Innovtaive Solidification Processing for Advanced Materials. Phase Selection of the Al2O3-Y2O3 System Controlled by Nucleation.
复制标题
先进材料的创新凝固加工。
DOI：
10.2320/matertrans.42.238
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发表时间：
2001
影响因子：
1.2
通讯作者：
Y. Waku
中科院分区：
文献类型：
--
作者：
Y. Mizutani;H. Yasuda;I. Ohnaka;Y. Waku
在Al_2O_3-Y_2O_3伪二元系富Al_2O_3部分存在两个共晶反应，一个是Al_2O_3-YAG(Y-Al-石榴石)平衡共晶反应，另一个是Al_2O_3-YAP(Y-Al-钙钛矿)亚稳态反应。根据凝固前的最高熔体温度和冷却速度，对成分范围为13.5mmol%Y2O3.的样品的共晶体系的选择进行了考察。当共晶成分从2173 K冷却时，当冷却速度大于5 K/S时，没有发生形核。将熔体加热到2273YAGK以上也抑制了 的成核。在亚稳共晶温度以下，由于抑制了YAG形核，产生了过冷熔体，从而形成了亚稳凝固路径。共晶体系的选择受YAG形核的控制。在2273 K附近，光学差热分析检测到NO的释放，但熔体最高温度对成核的影响表明，在2273 K附近熔体发生了一些变化。
There are two eutectic reactions in the Al2O3-rich portion of the Al2O3–Y2O3 pseudo-binary system; one is the Al2O3-YAG (yttrium-aluminum-garnet) equilibrium eutectic reaction, the other is the Al2O3-YAP (yttrium-aluminum-perovskite) metastable reaction. The selection of eutectic systems was examined, in terms of maximum melt temperatures before solidification and of cooling rates, for specimens in a composition range of 13.5 to 28.5 mol%Y2O3. YAG nucleation did not occur at a cooling rate of more than 5 K/s when eutectic composition specimens were cooled from 2173 K . Heating of the melt to temperatures above 2273 K also inhibited YAG nucleation. The inhibition of YAG nucleation led to the production of undercooling melt below the metastable eutectic temperature, and consequently resulted in a metastable solidification path. Selection of the eutectic system was controlled by YAG nucleation. At around 2273 K no heat release was detected by optical DTA measurement, although the effect of the maximum melt temperature on YAG nucleation suggested some change in the melt at about 2273 K.