Martensitic phase transformations of nanocrystalline NiTi shape memory alloys processed by repeated cold rolling

Autor(en)

Martin Peterlechner, Thomas Waitz, Christoph Gammer, Thomas Antretter

Abstrakt

The impact of grain size on the martensitic phase transformations of bulk nanocrystalline NiTi shape memory alloys processed by repeated cold rolling was systematically studied by differential scanning calorimetry and transmission electron microscopy. With decreasing grain size, the formation of the martensite is strongly suppressed and its thermal stability decreases. The effect of grain size on the intermediate R-phase is much smaller than that observed in the case of the martensite. Reversible and irreversible contributions to the Gibbs free energy of the martensite were obtained that are larger than those arising from the formation of martensite in coarse grains. Considering the dependence of the energy barrier on the transformation eigenstrain and the grain size, the experimental results were modelled within the general thermodynamic framework of the martensitic phase transformation.

Organisation(en)

Physik Nanostrukturierter Materialien

Externe Organisation(en)

Universität Münster, Montanuniversität Leoben

Journal

International Journal of Materials Research

Band

102

Seiten

634-642

Anzahl der Seiten

9

ISSN

1862-5282

DOI

https://doi.org/10.3139/146.110525

Publikationsdatum

2011

Peer-reviewed

Ja

ÖFOS 2012

1030 Physik, Astronomie, 103018 Materialphysik, 103030 Strahlenphysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/4a63350f-b90c-44a0-a664-0ec0323ec74d