An Energy Approach to Determine the Martensite Morphology in Nanocrystalline NiTi

Author(s)
Manuel Petersmann, Wolfgang Pranger, Thomas Waitz, Thomas Antretter
Abstract

The characteristic features of martensite in nanocrystalline Ni-50at %Ti are a compromise between interface and strain energies introduced into the material when a grain transforms from austenite to a finely laminated martensite structure. This paper focuses on the evaluation of these energies. Whereas for grain sizes <100nm a single laminate is frequently observed, in larger grains the higher strain energy of this structure leads to hierarchical twinning. As the predominant contribution the strain energy is computed by the finite element method. Interface energies at the twin- as well as the grain-boundaries are subsequently added. Suitable scaling relations yield the evolution of twin spacing and predict that multiple laminates become favorable at a diameter range of 70-90nm.

Organisation(s)
Physics of Nanostructured Materials
Journal
Advanced Engineering Materials
Volume
19
No. of pages
6
ISSN
1438-1656
DOI
https://doi.org/10.1002/adem.201600684
Publication date
04-2017
Publication status
Published
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics
Keywords
SHAPE-MEMORY ALLOYS, SEVERE PLASTIC-DEFORMATION, TRANSFORMATION, ACCOMMODATION
Portal url
https://ucris.univie.ac.at/portal/en/publications/an-energy-approach-to-determine-the-martensite-morphology-in-nanocrystalline-niti(b23ed749-8185-4e5c-83ed-203062c9ae75).html