Embedded atom calculations of unstable stacking fault energies and surface energies in intermetallics

Abstract

We performed embedded atom method calculations of surface energies and unstable stacking fault energies for a series of intermetallics for which interatomic potentials of the embedded atom type have recently been developed. These results were analyzed and applied to the prediction of relative ductility of these materials using the various current theories. Series of alloys with the B2 ordered structure were studied, and the results were compared to those in pure body-centered cubic (bcc) Fe. Ordered compounds with L1 2 and L1 0 structures based on the face-centered cubic (fcc) lattice were also studied. It was found that there is a correlation between the values of the antiphase boundary (APB) energies in B2 alloys and their unstable stacking fault energies. Materials with higher APB energies tend to have higher unstable stacking fault energies, leading to an increased tendency to brittle fracture.

Molecular dynamics investigation of the fracture behavior of nanocrystallineα-Fe

“…44 A comparison of this potential with other interatomic potentials available in the literature can be found in a previous paper. 45 This potential has also been tested previously in MS simulations of crack propagation in ␣-Fe single crystals. 29 MS is a technique designed to determine the minimum-energy configuration of a given system.…”

Crack-Tip Deformation Mechanisms in α-Fe and Binary Fe Alloys: An Atomistic Study on Single Crystals

“…These quantities were computed for the EAM potentials used in this work and are shown in Table II. The unstable stacking fault energies are computed for the known slip systems in bcc crystals, following the methodology of Farkas et al [18] In addition, it is useful to be able to compare the stress intensities at which events occur (either brittle crack advance or dislocation emission) in the simulations to those predicted by the Griffith and Rice criteria; the latter are defined by the relationships…”

Improving the fracture toughness of constituent phases and Nb-based in-situ composites by a computational alloy design approach

“…For designing against brittle fracture, some investigators [21,22,23] have focused on alloy effects on the unstable stacking energy [24] and the crack-tip dislocation-emission process, while others [17,[25][26][27][28][29] have emphasized the influence of alloying additions on the Peierls-Nabarro (P-N) barrier energy [30,31] and the mobility of dislocations moving away from the crack tip. A computational design approach had been developed to identify toughening or embrittling elements on the basis of the P-N barrier energy.…”