De-twinning and Texture Change in an Extruded AM30 Magnesium Alloy during Compression along Normal Direction. Issue 3 (March 2015)

• Record Type: Journal Article
• Authors: Sarker, D.; Friedman, J.; Chen, D.L.
• Is Part Of: Journal of materials science & technology. Volume 31:Issue 3(2015:Mar.)
• Page Start: 264
• Page End: 268
• Publication Date: 2015-03
• Subjects: Magnesium alloy -- Compressive deformation -- Twinning -- De-twinning -- Texture; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2014.11.018
• Languages: English
• ISSNs: 1005-0302

Abstract

Abstract : Twinning and de-twinning are the salient deformation mechanisms in hexagonal close-packed (hcp) metals. The aim of this study was to examine and quantify the de-twinning process involving a reversible motion of twin boundaries in an extruded AM30 magnesium alloy after re-compression along the normal direction (ND) of pre-compressed samples along the extrusion direction (ED). {10 1 ¯ 2} extension twins were first introduced at a compressive strain of 3.7% along the ED. The subsequent compressive deformation along the ND induced a gradual shrinkage of twins with increasing cumulative true strain, and the complete de-twinning occurred at a strain of ∼7.7%. The twin width decreased linearly with increasing true strain. Texture measurements verified the rotation of c -axes of hcp unit cells towards the anti-compression direction due to {10 1 ¯ 2} extension twinning after compression along the ED, and a gradual return of c -axes to the initial orientation due to twin shrinking or de-twinning during the following compression along the ND. The {10 1 ¯ 2} twinning corresponded to the formation of new texture components C{ 1 ¯ 2 1 ¯ 0}<0001> and D{01 1 ¯ 0}<0001> and a decrease in the initial texture components A{0001}<2 1 ¯ 1 ¯ 0> and B{0001}<10 1 ¯ 0>, while the twin shrinking or de-twinning was characterized by a gradual vanishing of components C{ 1 ¯ 2 1 ¯ 0}<0001> and D{01 1 ¯ 0}<0001> and an increase in the components A{0001}<2 1 ¯ 1 ¯ 0> and B{0001}<10 1 ¯ 0>.