Purification in the interaction between yttria mould and Nb-silicide-based alloy during directional solidification: A novel effect of yttrium

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• 作者：Limin Ma ; Xiaoxia Tang ; Bin Wang ; Lina Jia ; Sainan Yuan ; Hu Zhang ; ^{zhanghu@buaa.edu.cn}
• 关键词：Nb-silicide-based alloy ; Directional solidification ; Rare earth ; Ceramics
• 刊名：Scripta Materialia
• 出版年：2012
• 期刊代码：157_13596462
• 类别：et
• 出版时间：August, 2012
• 卷：67
• 期：3
• 页码：233-236
• 文件大小：890 K

摘要

Nb-silicide-based alloys were directionally solidified in yttria moulds. As a result of thermal dissociation of yttria, the alloys were slightly contaminated with oxygen, which caused a competitive oxidation between yttrium and hafnium. The addition of 0.15 at.%yttrium reduced the oxygen increment by 42%, because the buoyant inclusions concentrated around the top surface. The yttrium addition caused a significant purification of the interaction between the yttria mould and the Nb-silicide-based alloys during the directional solidification.