Interatomic Potential Construction For A-Ti

In recent years, titanium material and titanium alloy have aroused considerableattentions as functional materials in biomedical and other fields, because of itscorrosion resistance, biocompatibility and comprehensive mechanics capability. Ashigh temperature titanium material, nuclear reactor material and amorphous material,titanium material is also used in the field of science and technology. Sliping behaviorand amorphous behavior of titanium and titanium alloy are explained through thematerial structure of the atomic level, but the basic physical properties of relevantmetal or alloy can be represented by a reliable interatomic potential.Interatomic potential is one of the important methods of research on micro-levelmaterial performance, and it is also the foundation of molecular dynamics simulationmethod. In order to obtain the phase space trajectory of molecular dynamicssimulation and study the physical properties of materials, before the moleculardynamics simulation, the form of potential function should be ascertained first, andthe force between particles should be determined next according to the potentialfunction. Visibly, whether the interatomic potential is reasonable or not is theimportant factor of reliability and precision of the simulation results. Therefore, it isimportant to structure the reasonable and reliable interatomic potentials.In this paper, we simply introduce the related properties of Ti, summarize themain forms and the development situation of the interatomic potentials, and analyzetheir advantages and disadvantages. The model of Embedded Atom Method(EAM)potential is described in detail，and the interatomic potential function of α-Ti isconstructed under the EAM potential model. The experimental data of lattice constant,cohesive energy, elastic modulus, shear modulus and unrelaxed vacancy formationenergy are used to fit the potential parameters of α-Ti.The truncation distance of potential function has a significant impact on theperformance of potential function. In this paper the truncation function proposed byMishin is used for the truncation process. In order to examine the accuracy of the potential function built in this paper, we make a discussion on the potential functionstructure stability. The cohesive energies of hcp, bcc and fcc structure are calculatedby the potential function of Ti. Comparisons are made with the Rose curve. Thenumerical study shows that the cohesive energy of fcc structure is the lowest, thecohesive energy of hcp structure is a little higher than fcc structure and the bccstructure is the highest.