摘要
On the basis of the experimental data of phase equilibria and thermochemical properties available from literatures, a critical assessment for the Ni?Yb binary system was carried out using the CALPHAD (calculation of phase diagrams) method. The liquid phase is modeled as the associate model with the constituent species Ni, Yb and YbNi3, owing to the sharp change of the enthalpy of mixing of liquid phase at the composition of around 25% Yb (mole fraction). The terminal solid solutions FCC_A1 (Ni/Yb) and BCC_A2 (Yb) are described by the substitutional solution model with the Redlich?Kister polynomial. The intermetallic compounds, Yb2Ni17, YbNi5, YbNi3, YbNi2, α-YbNi and β-YbNi, are treated as strict stoichiometric compounds, since there are no noticeable homogeneity ranges reported for these compounds. A set of self-consistent thermodynamic parameters for the Ni?Yb binary system are obtained. According to the presently assessed results, the thermochemical properties and the phase boundary data can be well reproduced.
基于文献报道的相平衡和热化学实验数据,利用相图计算(Calphad)方法对Ni-Yb二元系进行热力学评估。考虑到液相混合焓在25%Yb(摩尔分数)附近有急剧变化,液相采用缔合物模型,组份为Ni、Yb Ni3和Yb;端际固溶体相包括FCC_A1(Ni)、FCC_A1(Yb)和BCC_A2(Yb),均采用亚规则溶体模型,并按照Redlich-Kister多项式进行描述;中间化合物Yb_2Ni_(17)、YbNi_5、YbNi_3、YbNi_2、α-YbNi和β-YbNi都没有明显的固溶度实验数据,均按严格计量比处理。优化得到的Ni-Yb二元系热力学参数自洽合理,能够很好地再现该体系的热化学性质和相图数据。
基金
Project(51271027)supported by the National Natural Science Foundation of China
Project(T201308)supported by Shenzhen Key Laboratory of Special Functional Materials of Shenzhen University,China
