金属间化合物NiAl晶格模型的蒙特卡罗模拟

采用巨正则系综蒙特卡罗(GCMC)方法对NiAl合金晶格模型在1273 K温度下的点缺陷浓度和Al原子相对化学活度等进行计算, 并与实验数据及缺陷关联模型(DCM)的理论计算结果进行比较. 结果发现, 当Ni原子比大于0.475时, 晶格模型能很好地描述NiAl合金的行为; 当Ni原子比小于0.475时, 空位浓度高于0.05, 晶格模型相互作用参数须作适当修正. 研究指出GCMC能很好地模拟晶格模型的热力学性质, DCM在描述富Ni区域Al空位的热激发行为和富Al区域Ni空位分布的关联性方面有局限性.

Monte Carlo Simulation of a Lattice Model for the Intermetallic Compound NiAl

The concentration of point defects and the relative activity of Al in NiAl alloys at 1273 K were calculated using the Monte Carlo method with the grand canonical ensemble (GCMC). The results were compared to experimental data and theoretical results obtained by the defect correlation model (DCM). When the proportion of Ni atoms is more than 0.475, the lattice model describes the behavior of NiAl alloys well. With a proportion of Ni atoms of less than 0.475 the parameters must be modified because the concentration of vacancies is more than 0.05. The GCMC method simulates the thermodynamic properties of the lattice model well. DCM is an accurate theoretical method but does not describe the thermal excitation of Al vacancies in rich Ni alloys or the correlation of Ni vacancies in rich Al alloys well.