A skull-aided technique for directional solidification of Nb-41Ni-40Ti hydrogen permeable alloy

作者：Yan Erhu; Li Xinzhong^*; Liu Dongmei; Su Yanqing; Guo Jingjie; Fu Hengzhi

来源：Journal of Crystal Growth, 2014, 391: 78-84.

DOI：10.1016/j.jcrysgro.2014.01.013

• Directional solidification
• Crystal morphology
• Bridgman technique
• Nb-Ni-Ti alloy

A skull-aided technique (SAT) for directional solidification (DS) of Nb-41Ni-40Ti alloy was developed to avoid the reaction between the alumina crucible and melt. By using SAT in alumina crucibles, DS experiments were performed in a Bridgman-type apparatus at a constant temperature gradient (G=20 K/mm) and growth rates ranging from 3 to 70 mu m/s. Continuous and well-aligned Nb-TiNi eutectic microstructure and planar solid/liquid interface were observed at 3-5 mu m/s. Higher growth rates resulted in the cellular/denciritic eutectic growth and even the appearance of primaily phase. The volume Fraction of well-aligned Nb rods (Vwell-Nb) in the eutectic microstructure decreased with increasing, growth rate (v), given as Vwell-Nb=11.8+109 exp(-v/13.93). No ceramic inclusions were found in DS ingot, which demonstrated that the SAT was very effective in avoiding the crucible-melt reaction for DS of Nb-41 Ni-40Ti alloy.

• 出版日期2014-4-1
• 单位哈尔滨工业大学