Nb—Ti—Ni合金的显微组织与氢渗透性能

研究了Nb50Ti25Ni25及Nb40Ti30Ni30合金的显微组织及氢渗透性能,并与贵金属Pd、Pd-Ag合金及纯Nb的氢渗透性能进行了比较.两种合金的显微组织均由先析出的bcc-Nb(Ti,Ni)固溶体和bcc-Nb(Ti,Ni) B2-TiNi共晶组成.随Ni、Ti合金元素含量增加,合金中共晶相的含量增加.氢渗透温度为673 K时,两种合金的氢渗透系数分别为1.71×10-8和1.03×10-8mol·in-1·s-1·Pa-0.5,接近Pd的氢渗透系数,略低于Pd-Ag合金的氢渗透系数.共晶相的比例增加有利于提高合金的抗氢脆性能,增加先析出相的比例可提高合金的氢渗透系数.适当调整合金元素含量可获得综合性能良好的氢渗透合金.

Microstructures and Hydrogen Permeation Characteristics of Nb-Ti-Ni Alloys

Microstructures and hydrogen permeation properties of Nb50Ti25Ni25 and Nb40Ti30Ni30 alloy were investigated, respectively, and compared with Nb, Pd and PdAg alloy. The results indicated that the microstructures of Nb50Ti25Ni25 and Nb40Ti30Ni30 alloy consisted of combinations of the primary bcc-(Nb, Ti) solid solution with the eutectic {bcc-(Nb, Ti)+B2-TiNi}. The volume fraction of the eutectic phase increased with addition of Ni and Ti, in contrast to decrease of the primary phase. The hydrogen permeabilities of Nb50Ti25Ni25 and Nb40Ti30Ni30 alloys at 673K were 1.71×10-8 molm-1s-1Pa-0.5 and 1.03×10-8 molm-1s-1Pa-0.5, respectively, which were in same magnitude level as pure Pd metal, but a little lower than that of PdAg alloy. Increasing of eutectic phase favored resistance to hydrogen embrittlement, while the hydrogen permeability of the alloys increased evidently with the increasing of the primary phase. Alloys with high hydrogen permeability and good resistance to hydrogen embrittlement can be designed by optimization Ni and Ti content.