High-temperature wettability and interactions between Hf-containing NbSi-based alloys and Y 2 O 3 ceramics with various microstructures
High-temperature wettability and interactions between Hf-containing NbSi-based alloys and Y 2 O 3 ceramics with various microstructures
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DOI：
10.1016/j.matdes.2017.10.060
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发表时间：
2018-01
影响因子：
8.4
通讯作者：
B. Wan;Huarui Zhang;M. Gao;P. Bai;Hu Zhang
中科院分区：
文献类型：
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作者：
B. Wan;Huarui Zhang;M. Gao;P. Bai;Hu Zhang
为了获得用于 NbSi 基合金定向凝固铸造的具有适当微观结构的改进模具壳，设计并表征了具有各种微观结构的 Y2O3 陶瓷。研究了NbSi基合金与Y2O3陶瓷的高温润湿性及相互作用机理。结果表明，当Y2O3微观结构发生变化时，熔融合金与陶瓷之间的润湿性存在特征转变。随着Y2O3陶瓷的开孔率从3.6%增加到27.2%，铺展率逐渐降低，表观平衡接触角从70.2°变为112.6°。润湿动力学分析表明，润湿过程中三重线的移动是由合金陶瓷界面中连续HfO2反应层的形成驱动的。随着Y2O3陶瓷的开孔率从3.6%增加到27.2%,合金基体中HfO2颗粒的含量先逐渐减少,随后增加。开孔率水平约为20.7%的Y2O3最有利于高纯含Hf NbSi基合金的定向凝固铸造。
To obtain improved mould shells with appropriate microstructures for directional solidification casting of NbSi-based alloys, Y2O3ceramics with various microstructures were designed and characterized. The mechanisms of high-temperature wettability and interactions between NbSi-based alloys and Y2O3ceramics were studied. The results showed that there was a characteristic transition in the wettability between the molten alloys and ceramics when the Y2O3microstructure changed. The spreading rate gradually decreased and the apparent equilibrium contact angle changed from 70.2° to 112.6° with the level of open porosity of Y2O3ceramics increasing from 3.6% to 27.2%. Wetting kinetics analyses indicated that the movement of the triple line during the wetting process was driven by the formation of continuous HfO2reaction layer in the alloy-ceramic interface. The content of HfO2particles inner the alloy matrix with the level of open porosity of Y2O3ceramics increasing from 3.6% to 27.2% initially gradually decreased and subsequently increased. Y2O3with open porosity level of about 20.7% were the most beneficial for directional solidification casting of high-purity Hf-containing NbSi-based alloys.