Modified embedded-atom potential for B2-MgAg

Abstract

Interatomic potentials for pure Ag and Mg–Ag alloy have been developed in the framework of the second nearest-neighbors modified embedded-atom method (MEAM). The validity and the transferability of the Ag potential were obtained by calculating physical, mechanical, thermal, and dislocation related properties. Since the {1 1 1}-generalized stacking fault energy curves obtained from first-principle calculations was used to develop the Ag potential, the critical resolved shear stress to move screw dislocations in Ag single crystal is in good agreement with the experimental data. By combining the ability of the potential to predict the surface energies with its accuracy in describing dislocation properties, the potential is thought to be a predictive model for analyzing the fracture properties of Ag. In addition, the performance of the potential was tested under dynamics conditions by predicting the melting temperature, where a good agreement with experimental value was found. The Ag-MEAM potential was then coupled to an existing Mg-MEAM potential to describe the properties of the binary system MgAg. While the heat of formation, the elastic constants, and the (1 1 0) γ-surface of the MgAg compound in the B2 phase were used to parameterize the potential, heat of formation for MgAg alloys with different stoichiometry, thermal properties of the B2-MgAg compound, as well as dislocation related properties in B2-MgAg compound were tested to validate the transferability of the potential. The heat of formation of Mg5Ag2, MgAg, and MgAg3, the elastic constants and the thermal properties of B2-MgAg obtained with the proposed potential align with first-principles and experimental data. In addition, the core structure of both 〈0 0 1〉 and 〈1 1 1〉 dislocations in {1 1 0} are in agreement with theoretical predictions, and the magnitudes of the critical resolved shear stress obtained at 0 K for both slip systems partially validate the slip behavior of B2-MgAg. Furthermore, the interaction between silver solute element and dislocations from the basal plane is correctly captured by the potential.

Atomistic Simulation of Interstitial Dislocation Loop Evolution under Applied Stresses in BCC Iron

“…When the shear stress is increased further, the loop totally changes its property from a prismatic loop to a shear loop, as shown in Figure (d)–(f), that is, the Burgers vector lies in the loop plane. Although the transition from a shear loop to a prismatic loop has been reported during bypass of an array of impenetrable particles by edge dislocations, obviously, the present results are different from such a process and the observed transition occurs in the opposite way: from a prismatic to a shear loop. Interestingly, after removing the shear stress, the prismatic loop reforms from the shear loop.…”

Artificial neural network interatomic potential for dislocation and fracture properties of Molybdenum

“…However, the computational cost still restricts first principles calculations to system sizes that do not exceed a few thousand atoms. As an alternative to DFT, semiempirical potentials such as embedded atom method (EAM) 7,8 and modified embedded atom method potentials (MEAM) [9][10][11][12][13] , bond order potentials [14][15][16] , and tight binding potentials 17,18 are employed nowadays in atomistic calculations to investigate plasticity and fracture. These approaches allow to calculate systems consisting of a few million atoms and hence simultaneously describe phenomena at different length scales.…”

Atomistic modeling of grain boundary behavior under shear conditions in magnesium and magnesium-based binary alloys

“…As listed in Table 1, the MgX (X=Al, Li, Y, Sn, Ca, Pb, Nd) potentials proposed by Lee and coworkers [14,[19][20][21], and the MgCa proposed by Groh [22] were derived from the pure magnesium potential proposed by Kim et al [14]. Using the magnesium potential recently proposed by Wu et al [17], Groh developed models for MgAg and MgY [23,24]. The MgLi potential of Karewar et al [25], and MgAl potential of Mendelev et al [26] were developed using the magnesium EAM potential proposed by Sun et al [13].…”

“…In this work, molecular statics calculations were performed using the (M)EAM implementations of the LAMMPS package [35], and atomic configurations were visualized using the OVITO package [36]. [13]; c [12]; d [14]; e [16]; f [15]; g [26]; h [25]; i [19]; j [20]; k [21]; l [22]; m [24]. n [23].…”

“…[13]; c [12]; d [14]; e [16]; f [15]; g [26]; h [25]; i [19]; j [20]; k [21]; l [22]; m [24]. n [23].…”