Activation of second-order <c+a> pyramidal slip and other secondary mechanisms in solid solution Mg-Zn alloys and their effect on tensile ductility. (1st January 2023)

• Record Type: Journal Article
• Authors: Shi, D.F.; Ma, A.; Pérez-Prado, M.T.; Cepeda-Jiménez, C.M.
• Is Part Of: Acta materialia. Volume 244(2023)
• Publication Date: 2023-01-01
• Subjects: Magnesium -- Slip trace analysis -- Ductility -- Deformation mechanisms -- Molecular dynamic (MD) simulations; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2022.118555
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: This work investigates the strain-dependent activation of second-order pyramidal slip and other non-basal systems with increasing tensile strain in a Mg-Zn alloy. With that purpose, a polycrystalline solid solution Mg-Zn alloy with ∼2 wt.% Zn (∼0.75 at. %) and with an average grain size of ∼36 μm was processed by casting, hot rolling and subsequent annealing. The slip activity with tensile strain was analyzed by electron backscattered diffraction (EBSD)-assisted slip trace analysis. Basal slip was found to be the dominant deformation mechanism at low strains (∼5-10%). However, at higher strains the activity of pyramidal slip increases significantly due to the hardening of basal slip by Zn solutes. Other non-basal deformation mechanisms, such as compression twinning, cross-slip and slip transfer between pyramidal planes, come into play also at higher strains and are shown to be induced by pyramidal slip. Molecular dynamics (MD) simulations have been used, in particular, to demonstrate the influence of pyramidal dislocations on the nucleation of compression twins. The large availability of deformation mechanisms at high strains contributes to improve the RT ductility of the Mg-Zn alloy. Graphical abstract: Image, graphical abstract