Microstructures and hydrogen permeability of directionally solidified Nb-Ni-Ti alloys with the Nb-NiTi eutectic microstructure
Microstructures and hydrogen permeability of directionally solidified Nb-Ni-Ti alloys with the Nb-NiTi eutectic microstructure
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DOI：
10.1016/j.intermet.2007.08.001
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发表时间：
2008-01-01
期刊：
影响因子：
4.4
通讯作者：
Aoki, Kiyoshi
中科院分区：
文献类型：
--
作者：
Kishida, Kyosuke;Yamaguchi, Yuji;Aoki, Kiyoshi
研究了在光学浮区炉中定向凝固的Nb-NiTi共晶合金的组织和透氢性能。当Nb-41Ni-40Ti合金在2.5 mm/h以下较慢的生长速度下生长时，可以获得沿生长方向平行排列的Nb棒的棒状共晶组织，氢的渗透性取决于膜内排列的Nb棒的相对方向。具有垂直于膜表面排列的Nb棒的试件的数值比具有平行于膜表面的Nb棒的试件大一个数量级。前者的最大值达2.60×10~(-8)molH~(2)m~(-1)S~(-1)pA~(-1/2)(673K)，是铸态Nb-NiTi共晶合金的两倍多。在573K~673K范围内未观察到氢脆现象，表明Nb-NiTi共晶结构抑制了Nb在氢渗透过程中的氢脆。(C)2007爱思唯尔有限公司。保留所有权利。
The microstructures and hydrogen permeability properties were investigated for Nb-NiTi eutectic alloys directionally solidified in an optical floating zone furnace. Rod-type eutectic microstructures with Nb rods aligned parallel to the growth direction are obtained with an alloy having a composition of Nb-41Ni-40Ti grown at relatively slow growth rates below 2.5 mm/h. The hydrogen permeability depends on the relative direction of aligned Nb rods within the membrane. The values for the specimens with Nb rods aligned perpendicular to the membrane surface are about an order of magnitude larger than those for the specimens with Nb rods parallel to the surface. The largest value for the former specimen is as high as 2.60 x 10(-8) mol H(2)m(-1) s(-1) Pa-1/2 (673 K), which is more than twice that reported for the as-cast Nb-NiTi eutectic alloy. No hydrogen embrittlement is observed between 573 and 673 K, indicating that the Nb-NiTi eutectic structure suppresses hydrogen embrittlement of Nb during hydrogen permeation. (c) 2007 Elsevier Ltd. All rights reserved.