Unraveling Recrystallization Mechanisms Governing Texture Development from Rare-Earth Element Additions to Magnesium
Unraveling Recrystallization Mechanisms Governing Texture Development from Rare-Earth Element Additions to Magnesium
复制标题
DOI：
10.1007/s11661-018-4520-8
复制
发表时间：
2018-05-01
影响因子：
2.8
通讯作者：
El Kadiri, Haitham
中科院分区：
文献类型：
--
作者：
Imandoust, Aidin;Barrett, Christopher D.;El Kadiri, Haitham
变形镁合金中织构组分的来源往往与稀土元素（REE）的添加有关，这是镁工艺中的一个长期问题。虽然它们对织构的影响是毋庸置疑的，但尚不清楚为什么某些织构组分，例如在传统镁合金中通常观察到的其他组分更受青睐。本研究的目的是确定在再结晶的早期阶段，这些稀土织构的机制负责。电子背散射衍射和透射电镜分析表明，稀土元素在含锌镁合金证实不连续动态再结晶。稀土元素促进各向同性生长的所有核产生通过膨胀机制。在成核过程中，稀土元素对取向选择的影响被解释为在同一晶粒中的[0001]泰勒轴和[0001]泰勒轴的多样化活动，其中[0001]旋转首先发生。在晶核生长过程中，当稀土元素的加入量足够时，没有观察到晶核的择优生长，而是在所有晶粒取向上各向同性地生长。这种现象归因于稀土元素偏析到晶界（GB），与先前的计算和理论结果一致（Barrett等人，Scripta Mater 146：46-50，2018），其在分离后显示出更各向同性的GB能量和迁移率。(C)2018年国际矿物、金属与材料协会和ASM国际
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 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 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. (C) The Minerals, Metals & Materials Society and ASM International 2018