Hugoniot States and Mie–Grüneisen Equation of State of Iron Estimated Using Molecular Dynamics

Crystals

Jun Ding¹  Xiangguo Zeng²  Huayan Chen²  Yuntian Wang²  Fang Wang³  Xin Yang⁴ 

[1] College of Mechanical Engineering, Chongqing University of Technology, Chongqing 400054, China;MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China;School of Materials and Energy, Southwest University, Chongqing 400715, China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China;

关键词: multiscale shock technique;    iron;    hugoniot states;    Mie–Grüneisen equation of state parameters;    molecular dynamics;   

DOI  :  10.3390/cryst11060664

来源: DOAJ

【 摘 要 】

The objective of this study was to develop a micromechanical approach for determining the Mie–Grüneisen EOS parameters of iron under the Hugoniot states. The multiscale shock technique (MSST) coupled with molecular dynamics (MD) simulations was employed to describe the shocked Hugoniot relation of single-crystal (SC) and nanocrystalline (NC) iron under high pressures. The Mie–Grüneisen equation of state (EOS) parameters, the cold pressure (P_c), the cold energy (E_c), the Grüneisen coefficient (γ), and the melting temperature (T_m) are discussed. The error between SC and NC iron results was found to be less than 1.5%. Interestingly, the differences in Hugoniot state (P_H) and the internal energy between SC and NC iron were insignificant, which shows that the effect of grain size (GS) under high pressures was not significant. The P_c and E_c of SC and NC iron calculated based on the Morse potential were almost the same with those calculated based on the Born–Mayer potential; however, those calculated based on the Born–Mayer potential were a little larger at high pressures. In addition, several empirical and theoretical models were compared for the calculation of γ and T_m. The Mie–Grüneisen EOSs were shown on the 3D contour space; the pressure obtained with the Hugoniot curves as the reference was larger than that obtained with the cold curves as the reference.

【 授权许可】

Unknown