Construction Of Interatomic Potential For B2-NiAl And Its Simple Application

The alloy materials have been applied in many fields, such as energy, chemicals and metallurgy due to its superior property. NiAl alloy, as a high-temperature structural material, has wide prospects of application, particularly in the aerospace industry. But its drawback is the poor room temperature ductility and low high-temperature strength which limited its application to a certain extent. The material performance depended on the composition, structure, alloying elements and other factors. So at the atomic level NiAl alloy performance of the study of microscopic mechanism has been a concern of the people.At atomic and molecular level, computer simulation based on the interaction potential is a main approach of material performance, which can provide help to understand different problems of material at the atomic level. This simulation develops a method to research the microstructure of material also .So it is very necessary to find the exact description of the interaction potential function.This treatise summarizes the main types and development situation of the interatomic potential for metals material, and simply introduces methods and development of Computer simulation based on the interaction potential. The model of Embedded Atom Method( EAM) potential is described in details .The interatomic potential of Ni, Al and B2-NiAl alloy has been constructed and are parameterized to fit the experimental data of lattice constant, cohesive energy, unrelaxed vacancy formation, elastic constants and anisotropy, which is pure-material Ni, Al and B2-NiAl alloy.In order to test the reasonableness of the potentials, it is compared with the cohesive energy curve of Rose et al which can be considered as a standard. The satisfactory results are obtained. Because the potential function is sensitive for the cutoff distance. So we handled the potential function by truncating processing in our model, and calculated cohesive energy of the Ni, Al and NiAl alloy. The results show that cohesive energy of Al and NiAl alloy is agreed with the experimental result, and Ni is relatively larger than the experimental values. We discussed the structure stability of Ni, Al and NiAl alloy. The results show that fcc (hcp) structure of Ni, Al is stable than bcc and bcc structure of NiAl alloy is stable than fcc (hcp), which is consistent with the practical case. The mono-vacancy formation energy of Ni, Al and NiAl alloy has been calculated, the results show that the calculated value of Al and NiAl alloy is agreed with the experimental data and other theoretical calculation well, while the results of Ni does not fit well. So we analyzed the reason that the calculated value of the cohesive energy and the mono-vacancy formation energy of Ni deviates from the experimental results and some theoretical results.