Deformation of magnesium during c-axis compression at low temperatures. (July 2017)

• Record Type: Journal Article
• Authors: Srivastava, Kinshuk; El-Awady, Jaafar A.
• Is Part Of: Acta materialia. Volume 133(2017)
• Page Start: 282
• Page End: 292
• Publication Date: 2017-07
• Subjects: Magnesium -- c-axis compression -- Dislocation interactions -- Pyramidal slip; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2017.05.039
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: In this study, large scale atomistically informed three-dimensional (3D) discrete dislocation dynamics (DDD) simulations were conducted to investigate the mechanical response of single crystal magnesium (Mg) during c-axis compression at low temperatures. In these simulations the plastic anisotropy of slip on pyramidal planes were accounted for to quantify the effects of misorientation, dislocation climb, and pyramidal 〈 c + a 〉 dislocation mobility. The simulation results show that a simple mobility rule based on the properties of edge and screw dislocations will lead to drastically different predictions of the response of Mg during c-axis compression as compared to a more rigorous dislocation orientation dependent mobility rule suggested by atomistic simulations. In addition, the current simulations suggest that plasticity is predominantly mediated by 〈 c + a 〉 slip on pyramidal I planes with less contribution from slip on pyramidal II planes. Furthermore, dislocation climb is observed to have an important effect even at low temperatures. A misorientation of the loading axis within a few degrees is shown to have a negligible effect on the results. The predicted dislocation microstructure are also shown to be in qualitative agreement with experimental results. Finally, the current simulations indicate that 〈 c + a 〉 pyramidal I slip cannot be neglected in crystal plasticity simulations.