Solution softening in magnesium alloys: the effect of solid solutions on the dislocation core structure and nonbasal slip

Abstract

There is a pressing need to improve the ductility of magnesium alloys so that they can be applied as lightweight structural materials. In this study, a mechanism for enhancing the ductility of magnesium alloys has been pursued using the atomistic method. The generalized stacking fault (GSF) energies for basal and prismatic planes in magnesium were calculated by using density functional theory, and the effect of the GSF energy on the dislocation core structures was examined using a semidiscrete variational Peierls-Nabarro model. Yttrium was found to have an anomalous influence on the solution softening owing to a reduction in the GSF energy gradient.

Effects of group II elements on the cold stretch formability of Mg–Zn alloys

“…Solute atoms alter the dislocation core structure, resulting in a variation in the Peierls stress [43]. The Peierls stress increases with the GSFE gradient [43][44][45]. As shown in Fig.…”

“…For both the basal and prismatic hai slips, the GSFEs for the Mg-Zn-X models were lower than that of the Mg-Zn model, and the GSFEs for the Mg-X models were lower than that of the pure Mg model. Solute atoms alter the dislocation core structure, resulting in a variation in the Peierls stress [43]. The Peierls stress increases with the GSFE gradient [43][44][45].…”

Effect of Micro-Alloying Elements on Deformation Behavior in Mg–Y Binary Alloys

“…Some recent papers have pointed out that the addition of Y atoms brings about a decrease in critical resolved shear stress in the non-basal plane by first-principle calculation. 34,35) In addition, the addition of Y atoms is reported to promote the formation of stacking faults in the matrix. Furthermore, these points, where the created stacking faults are due to the addition of Y atoms, are the origin of the activation of cross-slip.…”

Acceleration of the Particle Swarm Optimization for Peierls–Nabarro modeling of dislocations in conventional and high-entropy alloys

“…In this case the GSFE curve is the minimum energy path on the gamma surface, and the left part of the gamma surface will not be accessed even though a full gamma surface is available. Such an example for the prismatic dislocation in Mg can be found in [31].…”