Effect of Li element on shocking behavior of Fe-Li alloys

Understanding the effect of alloying elements on shock behaviors is significant for constitutive model of alloy materials at under dynamic high pressure. However, an in-depth understanding about the microscopic mecha-nism of alloying elements effect on plasticity and phase transition is still limited. In this work, applying non -equilibrium molecular dynamic (NEMD) simulations, shock-induced plasticity and phase transition of Fe-Li al-loys was investigated in terms of the compositions of Li, crystallographic direction and shock velocity. The results show that yield stress (or phase change pressure) of Fe-Li alloy was reduced doping Li element, and the large internal stresses caused by concentration of Li element effectively activated the nucleation and multiplication of dislocation loops. But with the increase of Li composition, phase transition is inhibited for shock along [111] direction because of stress release caused by multiplication of dislocation. There is a strong dependence between these microscopic processes and the law of plastic wave propagation. Moreover, with the increase of Li composition, the diversity of phase transition variants was inhibited for shock along [110] direction due to the destruction of initial stress and potential energy uniformity.

Automated summary

Understanding the effect of alloying elements on shock behaviors is significant for constitutive model of alloy materials at under dynamic high pressure. However, an in-depth understanding about the microscopic mechanism of alloying elements effect on plasticity and phase transition is still limited. In this work, the shock-induced plasticity and phase transition of Fe-Li alloys were investigated using non-equilibrium molecular dynamic (NEMD) simulations, in terms of the compositions of Li, crystallographic direction, and shock velocity. The results show that doping Li element reduces the yield stress (or phase change pressure) of Fe-Li alloy, and the concentration of Li element effectively activates the nucleation and multiplication of dislocation loops. However, with an increase in Li composition, phase transition is inhibited for shock along the [111] direction due to the stress release caused by dislocation multiplication. There is a strong dependence between these microscopic processes and the law of plastic wave propagation. Moreover, an increase in Li composition inhibits the diversity of phase transition variants for shock along the [110] direction, due to the destruction of initial stress and potential energy uniformity.