TY - JOUR

T1 - Unraveling Recrystallization Mechanisms Governing Texture Development from Rare-Earth Element Additions to Magnesium

AU - Imandoust, Aidin

AU - Barrett, Christopher D.

AU - Al-Samman, Talal

AU - Tschopp, Mark A.

AU - Essadiqi, Elhachmi

AU - Hort, Norbert

AU - El Kadiri, Haitham

PY - 2018/5/1

Y1 - 2018/5/1

N2 - The origin of texture components often associated with rare-earth element (REE) additions in wrought magnesium alloys is a long-standing problem in magnesium technology. While their influence on the texture is unquestionable, it is not yet clear why certain texture components, such as ⟨112¯1⟩||extrusiondirection, are favored over other components typically observed in traditional magnesium alloys. The objective of this research is to identify the mechanisms accountable for these RE textures during early stages of recrystallization. Electron backscattered diffraction and transmission electron microscopy analyses reveal that REEs in zinc-containing magnesium alloys corroborate discontinuous dynamic recrystallization. REEs promote isotropic growth for all nuclei generated through the bulging mechanism. During nucleation, the effect of REEs on orientation selection was explained by the diversified activity of both ⟨ 10 1 ¯ 0 ⟩ and [0001] Taylor axes in the same grain with a marked preference for [0001] rotations to occur first. During nuclei growth, no growth preference was observed when sufficient REEs are added in the zinc-containing magnesium alloys, instead isotropic nuclei growth across all grain orientations occurs. This phenomenon is attributed to REEs segregating to grain boundaries (GBs), in agreement with prior computational and theoretical results (Barrett et al., Scripta Mater 146:46–50, 2018) that show a more isotropic GB energy and mobility after segregation.

AB - The origin of texture components often associated with rare-earth element (REE) additions in wrought magnesium alloys is a long-standing problem in magnesium technology. While their influence on the texture is unquestionable, it is not yet clear why certain texture components, such as ⟨112¯1⟩||extrusiondirection, are favored over other components typically observed in traditional magnesium alloys. The objective of this research is to identify the mechanisms accountable for these RE textures during early stages of recrystallization. Electron backscattered diffraction and transmission electron microscopy analyses reveal that REEs in zinc-containing magnesium alloys corroborate discontinuous dynamic recrystallization. REEs promote isotropic growth for all nuclei generated through the bulging mechanism. During nucleation, the effect of REEs on orientation selection was explained by the diversified activity of both ⟨ 10 1 ¯ 0 ⟩ and [0001] Taylor axes in the same grain with a marked preference for [0001] rotations to occur first. During nuclei growth, no growth preference was observed when sufficient REEs are added in the zinc-containing magnesium alloys, instead isotropic nuclei growth across all grain orientations occurs. This phenomenon is attributed to REEs segregating to grain boundaries (GBs), in agreement with prior computational and theoretical results (Barrett et al., Scripta Mater 146:46–50, 2018) that show a more isotropic GB energy and mobility after segregation.

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=85044767959&partnerID=8YFLogxK

U2 - 10.1007/s11661-018-4520-8

DO - 10.1007/s11661-018-4520-8

M3 - Journal articles

AN - SCOPUS:85044767959

VL - 49

SP - 1809

EP - 1829

JO - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

JF - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

SN - 1073-5623

IS - 5

ER -