Influence of Ni on martensitic phase transformations in NiTi

0354830 - ÚFM 2011 RIV GB eng J - Journal Article
Frenzel, J. - George, E.P. - Dlouhý, Antonín - Somsen, Ch. - Wagner, M.F.-X. - Eggeler, G.
Influence of Ni on martensitic phase transformations in NiTi.
Acta Materialia. Roč. 58, č. 9 (2010), s. 3444-3458. ISSN 1359-6454. E-ISSN 1873-2453
R&D Projects: GA ČR GA106/09/1913
Institutional research plan: CEZ:AV0Z20410507
Keywords : NiTi shape memory alloys * Phase transformation temperatures * Thermodynamics * Vacuum arc melting
Subject RIV: JJ - Other Materials
Impact factor: 3.781, year: 2010

High-precision data on phase transformation temperatures in NiTi, including numerical expressions for the effect of Ni on MS,MF,AS,AF and T0, are obtained, and the reasons for the large experimental scatter observed in previous studies are discussed. Clear experimental evidence is provided confirming the predictions of Tang et al. 1999 [19] regarding deviations from a linear relation between the thermodynamic equilibrium temperature and Ni concentration. In addition to affecting the phase transition temperatures, increasing Ni contents are found to decrease the width of thermal hysteresis and the heat of transformation. These findings are rationalized on the basis of the crystallographic data of Prokoshkin et al. 2004 [68] and the theory of Ball and James [25].
Permanent Link: http://hdl.handle.net/11104/0193745