Coupled growth of unidirectionally solidified Al2O3-YAG eutectic ceramics
Coupled growth of unidirectionally solidified Al2O3-YAG eutectic ceramics
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DOI：
10.1016/s0022-0248(02)01655-x
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发表时间：
2002-10-01
影响因子：
1.8
通讯作者：
Waku, Y
中科院分区：
文献类型：
--
作者：
Mizutani, Y;Yasuda, H;Waku, Y
研究了Al_2O_3-YAG共晶系在13.5- 28.5mol%Y_2O_3范围内的定向凝固。生长速率范围为1.4 x 10（-7）至2.8 x 10（-5）m/s，温度梯度约为1 x 10（4）K/m。在小于18.5mol%Y2O3的组成下观察到具有树枝状形状的初级Al 2 O3晶体，而在大于20.5mol%Y2O3的组成下观察到初级YAG晶体。耦合生长只发生在18.5摩尔% Y2 O3（共晶组合物）和20.5摩尔% Y2 O3的试样。生长速率下降到1.4 × 10-7 m/s并没有延伸到耦合生长区。耦合生长的组成范围是约2摩尔%的Y2 O3周围的共晶组成，共晶间距往往偏离关系λ（2）V =常数在低生长速率。由于小面生长的非平面界面在低生长速率下不会引起凝固前沿的任何温度降低，因此在受限的组成范围内发生耦合生长。(C)2002 Elsevier Science B. V.保留所有权利。
Unidirectional solidification of the Al2O3-YAG eutectic system in a composition range of 13.5-28.5 mol% Y2O3 was investigated. Growth rates ranged from 1.4 x 10(-7) to 2.8 x 10(-5) m/s with a temperature gradient of roughly 1 x 10(4) K/m. Primary Al2O3 crystals with dendritic shapes were observed at compositions of less than 18.5 mol% Y2O3, while primary YAG crystals were observed at compositions of more than 20.5 mol% Y2O3. Coupled growth occurred only in the specimens of 18.5 mol % Y2O3 (eutectic composition) and 20.5 mol % Y2O3. The decrease of the growth rate down to 1.4 x 10-7 m/s did not extend to the coupled growth zone. The composition range for coupled growth was about 2 mol% Y2O3 around the eutectic composition, and eutectic spacing tended to deviate from the relationship lambda(2)V = constant at a low growth rate. The non-planar interface due to the faceted growth did not cause any temperature decrease of the solidifying front at low growth rates, and consequently coupled growth occurred in the restricted composition range. (C) 2002 Elsevier Science B.V. All rights reserved.