Interfacial defects in Ti-Nb shape memory alloys
Interfacial defects in Ti-Nb shape memory alloys
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DOI：
10.1016/j.actamat.2008.02.045
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发表时间：
2008-08-01
期刊：
影响因子：
9.4
通讯作者：
Miyazaki, S.
中科院分区：
文献类型：
--
作者：
Chai, Y. W.;Kim, H. Y.;Miyazaki, S.
研究了铌含量为20 ~ 24 at的Ti-Nb二元合金中马氏体（α′）/马氏体（α′）和母晶（β′）/马氏体（α′）界面的组织。%被调查。alpha “ /alpha ”和beta/alpha “接口都由一系列{2 (1)/ bar 11}(beta)//{110}（alpha ”）梯田和台阶组成，当从侧面看时（接近[001](alpha ")）。发现了界面缺陷，特别是沿台阶-台阶界面结构叠加的相变断路（b,h）。它们负责适应沿着alpha“/alpha”和beta/alpha”界面的大部分转换应变。利用参数b和h，基于拓扑模型的“α”习惯面预测与现象学理论预测和实验观测结果吻合较好。Ti-20Nb合金的α”习惯面接近{7 (5)/ bar(5) / bar}(β)， Ti-22Nb和Ti-24Nb合金的α”习惯面向{4 (3)/ bar(3) / bar}（β）移动。沿β / α”界面的剩余转变应变被（111）（α”）上的1型孪晶容纳，Burgers向量b（LIS）接近α”（相当于β）。(C) 2008材料学报Elsevier Ltd.出版。版权所有。
The structure of the martensite (alpha '')/marten site (alpha '') and parent (beta)/martensite (alpha '') interfaces in a series of binary Ti-Nb alloys with Nb content ranging from 20 to 24 at.% was investigated. Both the alpha ''/alpha '' and beta/alpha '' interfaces comprised a series of {2 (1) over bar 11}(beta)//{110}(alpha '')terraces and steps when viewed edge-on (close to [001](alpha '')). Interfacial defects, particularly the transformation disconnections (b,h) superimposed along the terrace-step interface structure, have been identified. They were responsible for accommodating most of the transformation strain along the alpha ''/alpha '' and beta/alpha '' interfaces. Using the parameters b and h, the prediction of the alpha '' habit plane based on the topological model agreed well with the prediction from the phenomenological theory as well with experimental observations. The alpha '' habit plane in Ti-20Nb alloy is close to {7 (5) over bar(5) over bar}(beta) and moves towards {4 (3) over bar(3) over bar}(beta) in Ti-22Nb and Ti-24Nb alloys. The remaining transformation strain along the beta/alpha '' interface was found to be accommodated by Type 1 twinning on (111)(alpha '') with Burgers vector b(LIS) close to alpha '' (equivalent to beta). (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.