Hydrogen permeable Ta-Ti-Ni duplex phase alloys with high resistance to hydrogen embrittlement

作者：Luo W; Ishikawa K; Aoki K^*

来源：Journal of Alloys and Compounds, 2008, 460(1-2): 353-356.

DOI：10.1016/j.jallcom.2007.06.061

• hydrogen absorption
• hydrogen diffusion
• microstructures
• hydrogen embrittlement

Crystal structures, microstructures and hydrogen permeability Phi of as-cast Ta-TiNi alloys on the line connecting the compositions of the primary (Ta, Ti) and the ternary eutectic phases have been investigated to find out highly hydrogen permeable duplex phases alloys with high resistance to the hydrogen embrittlement. The alloys on this line show microstructures of (1) the eutectic {(Ta, Ti) + TiNi} phase, (2) the primary (Ta, Ti) phase + the eutectic {(Ta, Ti) + TiNi} phase, and (3) the (Ta, Ti) solid solution, although a little amount of unidentified (impurity) phases are included in these samples. The value of Phi increases with increasing Ta content and the volume fraction of the primary (Ta, Ti) phase, which indicates that the primary phase contributes mainly to the hydrogen permeation. The Ta56Ti23Ni21 alloy, containing the 61 vol.% primary phase, shows the highest Phi of 2.18 x 10(-8) mol H-2 m(-1) s(-1) Pa-0.5 at 673 K, which is 1.3 times higher than that of the previous most high Phi alloy (Ta53Ti28Ni19). The more Ta-rich alloys on this line, i.e., containing a small amount of the eutectic phase, are broken down by the hydrogen embrittlement, suggesting that the eutectic phase suppresses the hydrogen embrittlement.

• 出版日期2008-7-28