A modified W-W interatomic potential based on ab initio calculations

作者：Wang J^*; Zhou Y L; Li M; Hou Q

来源：Modelling and Simulation in Materials Science and Engineering, 2014, 22(1): 015004.

DOI：10.1088/0965-0393/22/1/015004

• tungsten potential
• vacancy
• self-interstitial atom
• molecular dynamics simulations

In this paper we have developed a Finnis-Sinclair-type interatomic potential for W-W interactions that is based on ab initio calculations. The modified potential is able to reproduce the correct formation energies of self-interstitial atom (SIA) defects in tungsten, offering a significant improvement over the Ackland-Thetford tungsten potential. Using the modified potential, the thermal expansion is calculated in a temperature range from 0 to 3500 K. The results are in reasonable agreement with the experimental data, thus overcoming the shortcomings of the negative thermal expansion using the Derlet-Nguyen-Manh-Dudarev tungsten potential. The W-W potential presented here is also applied to study in detail the diffusion of SIAs in tungsten. We reveal that the initial SIA initiates a sequence of tungsten atom displacements and replacements in the < 111 > direction. An Arrhenius fit to the diffusion data at temperatures below 550 K indicates a migration energy of 0.022 eV, which is in reasonable agreement with the experimental data.

• 出版日期2014-1
• 单位四川大学