Atomistic study of fundamental character and motion of dislocations in intermetallic Al2Cu

Abstract

Atomic scale study of the character and motion of dislocations in Al 2 Cu will provide insights into understanding the superior mechanical properties of Al-Al 2 Cu alloys. Using atomistic simulations, we studied seven potential slip systems (110)<001>, (010)<001>, (310)<001>, (010)<100>, (110)<1 0>, (110) < 1> and (112) < > in Al 2 Cu with body centered tetragonal structure. We found that three edge dislocations with Burgers vector <001> on glide planes (110), (010), and (310), show an extended core and are predicted to be glissile at room and moderate temperatures. Other four edge dislocations associated with slip systems (010)<100>, (110)<1 0>, (110) < 1> and (112) < > and three screw dislocations with Burgers vectors <001>, <110>, and < > show a condensed core, and exhibit significantly higher Peierls barrier for glide at room temperature. Furthermore, the interaction of dislocation dipole associated with slip system (110)<001> results in the climb of the extended-core dislocation at room temperature through three stages: the extended core condenses, the leading partial dislocation climbs accompanying the creation of vacancies (resulting in a non-planar core), and the two partials with non-planar core collectively glide on the neighboring slip planes associated with atomic shuffles.

Superplastic Deformation of Al–Cu Alloys after Grain Refinement by Extrusion Combined with Reversible Torsion

“…This situation was connected with the fact that for Al 2 Cu phase, the processes of recovery can proceed easier than for the α-Al phase. The obtained results are in accordance with the literature [ 24 , 25 ]. During deformation in Al 2 Cu phase, we observed a mechanism connected with non-conservative motion of glide dislocation.…”

Dislocations interaction induced structural instability in intermetallic Al2Cu

“…30 Using atomistic simulations with empirical potentials, we studied core structure of dislocations associated with these slip systems. 29 The potentials have been tested to well reproduce lattice constants, cohesive energy, elastic properties, as compared to first-principles density function theory calculations and experiments. 30,31 Additional calculation details specific to different separations are included in the Supplementary Information.…”

“…27,28 Using molecular dynamics (MD) simulations with empirical potentials, we studied core structure of <001> dislocation on (110) plane. 29 Disregistry analysis across the shear plane revealed that a [001] dislocation on (110) plane dissociates into two partials bonded by a planarextended core with a separation >1.5 nm (also see Figs. S1 and S2 in Supplementary Information).…”

Optimization of a Solution Treatment in the Al-Cu-Mg-Ag Alloy via a Microstructural Investigation

“…Additionally, large particles remain in the grain boundaries due to the insufficient solution treatment temperature. It is well known that large particles in grain boundaries act as crack initiation sites, resulting in an increase in the brittleness [6,19,20]. On the other hand, the conventional solution treatment temperature of Al 2xxx alloys with 5.0 wt.% < Cu < 7.0 wt.% is high enough to induce the grain growth of Al grains.…”