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

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 1 ¯ 0 〉 , (110) 1 2 〈 1 1 ¯ 1 〉 and (112) 1 2 〈 1 ¯ 1 ¯ 1 〉 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 1 ¯ 0 〉 , (110) 1 2 〈 1 1 ¯ 1 〉 and (112) 1 2 〈 1 ¯ 1 ¯ 1 〉 and three screw dislocations with Burgers vectors 〈 001 〉 , 〈 110 〉 , and 1 2 〈 1 ¯ 1 ¯ 1 〉 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.