Nb-Mo(Co)合金相结构及其氢渗透特性研究

Phase structure and hydrogen permeation properties of Nb-Mo(Co) alloys

为了研究合金化对Nb相结构和渗氢性能的影响,以Nb-14Mo和Nb-7Mo-7Co合金为研究对象,采用精细X射线衍射(XRD)分析、吸放氢压强—成分—等温曲线(PCT)分析和三点抗弯实验。研究表明:熔炼制备的Nb-14Mo和Nb-7Mo-7Co合金均为铌的固溶体,氢化后生成Nb H0.95氢化物相,较小原子半径的Mo和Co添加会引起固溶体及其氢化物相晶胞参数减小和晶胞畸变收缩。同Nb-14Mo合金相比,Nb-7Mo-7Co合金的氢化物生成焓值较高(-35.8 k J/mol),氢化处理前后的Nb-7Mo-7Co合金膜均具有较好的抗弯机械性能,表明Co部分替换Mo,能降低氢化物的稳定性,有利于氢化物脱氢,并能够改善Nb-14Mo合金的抗弯机械性能。

To investigate the effects of elemental alloying on phase structure and hydrogen permeation properties of Nb metal,the X-ray diffraction（ XRD） analysis,Pressure-Composition-Temperature（ PCT） measurement and three-point bending test were conducted. The results indicated that Nb-14 Mo and Nb-7Mo-7Co alloy samples were both Nb solid solutions with BCC structure. After hydrogenation treatment,Nb H0. 95 phase was formed and the lattice parameters（ a,b,c,V）decreased,which could be attributed to the smaller atomic radius of Mo or Co than that of Nb.Compared with those obtained in Nb-14 Mo alloy, higher formation enthalpy of the hydride（-35. 8 k J/mol） and better anti-bending mechanical property were obtained in Nb-7Mo-7Co alloy sample. It suggested that partial replacement of Mo with Co could weaken structure stability ofNb H0. 95 phase,facilitate its dehydrogenation process,and improve the anti-bending mechanical property.