Impact of deformation faceting on {1 0 (1)over-bar 2}, {1 0 (1)over-bar 1} and {1 0 (1)over-bar3} embryonic twin nucleation in hexagonal close-packed metals
Impact of deformation faceting on {1 0 (1)over-bar 2}, {1 0 (1)over-bar 1} and {1 0 (1)over-bar3} embryonic twin nucleation in hexagonal close-packed metals
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DOI：
10.1016/j.actamat.2014.02.018
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发表时间：
2014-05-15
期刊：
影响因子：
9.4
通讯作者：
El Kadiri, Haitham
中科院分区：
文献类型：
--
作者：
Barrett, Christopher D.;El Kadiri, Haitham
应力下的晶界可能会出现断线堆积。堆积物周围的增强畸变场可以通过形成低能量边界来松弛，但不需要显着改变取向差。在变形刻面中，取向差的变化是由界面楔向错偶极子介导的，而如果新刻面保留了原始断开步骤的不兼容性，则断开内容仍然存在。任何在一个小面上滑动的断开可能会进入并沿着相邻的小面（交叉小面）滑动，前提是它跨越向错势垒转变为移动缺陷。 {1 0 (1) over bar 2} 和 {1 0 (1) over bar 1} 是六方密排金属中的特殊孪晶边界，可以将滑移位错转化为断开连接，而断开连接往往会通过小面成核而堆积和松弛。因此，这些双胞胎可能会进入其他移动边界，从而使交叉面成为吸收和克服滑动障碍的一种方式，而不会牺牲太多的移动性。在本文中，我们提供了低能边界、向错和断开变换的详细表征，这些边界、向错和断开变换可能分别干预{1 0 (1) over bar 2}和{1 0 (1) over bar 1}孪晶面，并扩展到{1 0 (1) over bar 3}孪晶。我们进一步表明，这种刻面促进了大量双胞胎胚胎的形成，并促进它们成熟为适合晶状体双胞胎繁殖的大尺寸。我们应用了三色复数概念，该概念是我们最近针对 {1 0 (1) over bar 2} 双刻面引入的。 (C) 2014 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
A crystal boundary under stress may develop pile-ups of disconnections. The augmented distortion field around the pile-up may relax by forming a low-energy boundary, but one which does not require a significant change in misorientation. In deformation faceting, the change in misorientation is mediated by an interfacial wedge disclination dipole, while disconnection content persists if the new facet preserves the incompatibility of the original disconnection steps. Any disconnection gliding on one facet may enter and glide along the adjacent facet (cross-facet), provided it transforms across the disclination barrier into a mobile defect. {1 0 (1) over bar 2} and {1 0 (1) over bar 1} are special twin boundaries in hexagonal close-packed metals that can convert slip dislocations into disconnections which tend to pile-up and relax via facet nucleation. Thus, these twins may facet into other mobile boundaries which enable cross-faceting as a way to absorb and overcome slip barriers without sacrificing much of their mobility. In this paper, we provide a detailed characterization of the low-energy boundaries, disclinations and disconnection transformations that may separately intervene in {1 0 (1) over bar 2} and {1 0 (1) over bar 1} twin faceting, with extensions to {1 0 (1) over bar 3} twinning. We further show that this faceting promotes formation of bulk twin embryos and facilitates their maturity into large dimensions appropriate for lenticular twin propagation. We apply the trichromatic complex concept, which we recently introduced for {1 0 (1) over bar 2} twin faceting. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.