【摘 要】
：
The compositional window in Nb-Ni-Ti alloys leading to the crystallization of primary α-Nb phase and the eutectic (α-Nb + NiTi) phase is of high technical relevance due to its favorable properties wit
【机 构】
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桂林电子科技大学材料科学与工程学院
【出 处】
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第十七届全国相图学术会议暨相图与材料设计国际研讨会
论文部分内容阅读
The compositional window in Nb-Ni-Ti alloys leading to the crystallization of primary α-Nb phase and the eutectic (α-Nb + NiTi) phase is of high technical relevance due to its favorable properties with respect to hydrogen permeation.The solidification behavior of Nb-Ni-Ti alloys in the primary α-Nb phase region is investigated to reveal the potential solidification paths.The study is based on the characterization of as-cast microstructures in combination with numerical calculations of solidification paths using the CALPHAD method coupled with a microsegregation model.Four different kinds of solidification paths depending on initial composition and cooling rate are found.Correspondingly, a new compositional window appropriate for hydrogen permeation is established in the primary α-Nb phase region.The variation of the hydrogen permeability of the alloys in this window is surprisingly high.High Nb content and Ni/Ti ratio lead to a high permeability.Nb55Ni20Ti25 shows the highest permeability at 673K, particularly 2.9×10-8mol H2 m-1s-1Pa-1/2.This is about 1.8 times higher than that of pure Pd.
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