Strain-induced phase transformation of a thin Co film on flexible substrates

Author(s)
V. M. Marx, C. Kirchlechner, B. Breitbach, M. J. Cordill, D. M. Toebbens, T. Waitz, G. Dehm
Abstract

The strain-induced FCC to HCP phase transformation of a two phase Co film on polyimide was investigated by performing a tensile test in an X-ray diffractometer. During straining of the 2 μm thick film, the intensity of the (002)

FCC peak continuously decreases at engineering strains between 2 and 8% and remains constant at higher strains. Complementary in situ tensile tests under an optical light microscope showed crack formation at 6.7% and crack saturation at around 10% engineering strain. The strain-induced phase transformation starts before the first cracks form leading to a maximum lattice strain of approximately 0.9% as initiation strain measured from the (101¯1)

HCP peak with the sin

2ψ method which converts to a film stress of approximately 1270 ± 150 MPa. It could be revealed that a strain-induced phase transformation can enhance the ductility and therefore delay the crack onset of a thin cobalt film.

Organisation(s)
Physics of Nanostructured Materials
External organisation(s)
Max-Planck-Institut für Eisenforschung, Max-Planck-Gesellschaft, Montanuniversität Leoben, Österreichische Akademie der Wissenschaften (ÖAW), Helmholtz-Zentrum Berlin für Materialien und Energie, Helmholtz-Zentrum Dresden-Rossendorf
Journal
Acta Materialia
Volume
121
Pages
227-233
No. of pages
7
ISSN
1359-6454
DOI
https://doi.org/10.1016/j.actamat.2016.09.015
Publication date
12-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics
Keywords
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials, Ceramics and Composites, Metals and Alloys, Polymers and Plastics
Portal url
https://ucrisportal.univie.ac.at/en/publications/straininduced-phase-transformation-of-a-thin-co-film-on-flexible-substrates(cf0543a3-51b1-4baf-bb4d-406c6ea9992c).html