Zr-Nb合金的吸氢性能与相变行为

Hydrogen Absorption Behavior of Zr-Nb Alloy and Phase Transformations

摘要:

通过PCT（pressure-composition-temperature）吸氢性能实验研究了温度（700~900 ℃）和Nb含量（1%~30%，质量分数）对Zr-Nb合金吸氢性能的影响。结果表明，温度的变化对β-Zr相和δ氢化锆相的两相平衡有较大影响，β-Zr相较δ氢化锆相的高温稳定性更强。Nb的添加降低了体系与H结合的稳定性，随着Nb含量的增加，合金的最大吸氢量明显减少。相同温度条件下，β-Zr相和δ氢化锆相两相平台所对应的平衡氢分压随Nb含量增加而升高。Nb降低合金最大吸氢量的主要原因是高氢含量的δ相NbH2氢化物在低压下不能稳定存在。

关键词:Zr-Nb合金;PCT;吸氢性能;氢化锆

Abstract:

To investigate the hydrogen absorption properties of Zr-Nb alloys, the PCT (pressure-composition-temperature) measurements for Zr-Nb alloys with different Nb contents (1wt%~30wt%) were carried out under low pressure in the temperature range of 700~900 oC. The results indicate that the temperature affects significantly the two-phase equilibrium of β-Zr and δ zirconium hydride. β-Zr shows more stable characters than δ zirconium hydride in the system under the high temperature condition. Nb decreases the binding stability between the system and H, and the equilibrium hydrogen content of the zirconium alloy decreases apparently with the Nb content increasing. The main reason for the decreasing of hydrogen absorption is that δ NbH2 with high hydrogen content cannot exist under the condition of low pressure.

Key words:Zr-Nb alloy; PCT; absorption property; zirconium hydride