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Titolo:
Stabilisation of martensite by applying compressive stress in Cu-Al-Ni single crystals
Autore:
Picornell, C; Pons, J; Cesari, E;
Indirizzi:
Univ Illes Balears, Dept Fis, E-07071 Palma de Mallorca, Spain Univ Illes Balears Palma de Mallorca Spain E-07071 ma de Mallorca, Spain
Titolo Testata:
ACTA MATERIALIA
fascicolo: 20, volume: 49, anno: 2001,
pagine: 4221 - 4230
SICI:
1359-6454(200112)49:20<4221:SOMBAC>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
TRANSFORMATION; ALLOYS; PSEUDOELASTICITY; DEFORMATION; MECHANISM; PHASE; ZN;
Keywords:
shape memory; martensite; stress-strain relationship measurements; differential thermal analysis (DTA); transmission electron microscopy (TEM);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
18
Recensione:
Indirizzi per estratti:
Indirizzo: Picornell, C Univ Illes Balears, Dept Fis, Cra de Valldemossa Km 7-5, E-07071 Palma de Mallorca, Spain Univ Illes Balears Cra de Valldemossa Km 7-5 Palma de Mallorca Spain E-07071
Citazione:
C. Picornell et al., "Stabilisation of martensite by applying compressive stress in Cu-Al-Ni single crystals", ACT MATER, 49(20), 2001, pp. 4221-4230

Abstract

Compression tests have been carried out for a Cu-AI-Ni single crystal at temperatures well above the martensitic transformation. near the transformation or below it (in martensitic state). The composition was selected in order to obtain either beta-beta' or beta-gamma' thermal martensitic transformations, after suitable thermal treatments. The characteristics of the martensitic transformation and structural changes after the compression tests have been studied by means of calorimetry (DSC) and TEM. The obtained resultsshow that when a compressive stress is applied on quenched samples (TTA treatment, beta-beta' thermal transformation) a beta beta-(beta')-gamma' transformation or a beta'-gamma' one are stress-induced, depending whether the initial state is the parent or the martensitic phase. For aged samples (TTBtreatment, beta-gamma' thermal transformation) the application of stress brings about the beta-gamma' transformation or gamma' re-orientation, depending on the initial state. In all the cases a notable martensite stabilisation is observed only when the stress-strain loop is not closed. that means when a permanent strain remains in the material after unloading. A direct relationship between the applied deformation when stressing the sample and the degree of stabilisation has been obtained for different strain values (between 5% and 12%) and for each set of samples (TTA and TTB). At the same time, the evolution of the characteristics of the martensitic phases with thedegree of deformation has been studied. The stress induced stabilisation mechanism is related to the presence of non-twinned gamma' martensite which makes difficult the retransformation to the parent phase. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.

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Documento generato il 30/09/20 alle ore 09:37:26