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On the multiplication of dislocations during martensitic transformations in NiTi shape memory alloys
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SYSNO ASEP 0354828 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title On the multiplication of dislocations during martensitic transformations in NiTi shape memory alloys Author(s) Simon, T. (DE)
Kröger, A. (DE)
Somsen, Ch. (DE)
Dlouhý, Antonín (UFM-A) RID, ORCID
Eggeler, G. (DE)Number of authors 5 Source Title Acta Materialia. - : Elsevier - ISSN 1359-6454
Roč. 58, č. 5 (2010), s. 1850-1860Number of pages 11 s. Language eng - English Country GB - United Kingdom Keywords NiTi ; Martensitic transformations ; Dislocation multiplication mechanism ; Martensite variants ; Dislocations Subject RIV BM - Solid Matter Physics ; Magnetism R&D Projects GA106/09/1913 GA ČR - Czech Science Foundation (CSF) CEZ AV0Z20410507 - UFM-A (2005-2011) UT WOS 000274931200036 DOI 10.1016/j.actamat.2009.11.028 Annotation In situ and post-mortem diffraction contrast transmission electron microscopy (TEM) was used to study the multiplication of dislocations during a thermal martensitic forward and reverse transformation in a NiTi shape memory alloy single crystal. An analysis of the elongated dislocation loops which formed during the transformation was performed. It is proposed that the stress field of an approaching martensite needle activates an in-grown dislocation segment and generates characteristic narrow and elongated dislocation loops which expand on {1 1 0}B2 planes parallel to {0 0 1}B190 compound twin planes. The findings are compared with TEM results reported in the literature for NiTi and other shape memory alloys. It is suggested that the type of dislocation multiplication mechanism documented in the present study is generic and that it can account for the increase in dislocation densities during thermal and stress-induced martensitic transformations in other shape memory alloys. Workplace Institute of Physics of Materials Contact Yvonna Šrámková, sramkova@ipm.cz, Tel.: 532 290 485 Year of Publishing 2011
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