title: Deformation-induced grain growth and twinning in nanocrystalline palladium thin films.
abstract: The microstructure and mechanical properties of nanocrystalline Pd films prepared by magnetron sputtering have been investigated as a function of strain. The films were deposited onto polyimide substrates and tested in tensile mode. In order to follow the deformation processes in the material, several samples were strained to defined straining states, up to a maximum engineering strain of 10%, and prepared for post-mortem analysis. The nanocrystalline structure was investigated by quantitative automated crystal orientation mapping (ACOM) in a transmission electron microscope (TEM), identifying grain growth and twinning/detwinning resulting from dislocation activity as two of the mechanisms contributing to the macroscopic deformation. Depending on the initial twin density, the samples behaved differently. For low initial twin densities, an increasing twin density was found during straining. On the other hand, starting from a higher twin density, the twins were depleted with increasing strain. The findings from ACOM-TEM were confirmed by results from molecular dynamics (MD) simulations and from conventional and in-situ synchrotron X-ray diffraction (CXRD, SXRD) experiments.
authors.affiliation: Technische Universität Darmstadt (TUD), KIT-TUD Joint Research Laboratory Nanomaterials, 64287 Darmstadt, Germany ; Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology (INT), 76021 Karlsruhe, Germany.
authors.forename: Aaron
authors.initials: A
authors.lastname: Kobler
authors.forename: Jochen
authors.initials: J
authors.lastname: Lohmiller
authors.forename: Jonathan
authors.initials: J
authors.lastname: Schäfer
authors.forename: Michael
authors.initials: M
authors.lastname: Kerber
authors.forename: Anna
authors.initials: A
authors.lastname: Castrup
authors.forename: Ankush
authors.initials: A
authors.lastname: Kashiwar
authors.forename: Patric A
authors.initials: PA
authors.lastname: Gruber
authors.forename: Karsten
authors.initials: K
authors.lastname: Albe
authors.forename: Horst
authors.initials: H
authors.lastname: Hahn
authors.forename: Christian
authors.initials: C
authors.lastname: Kübel
keywords: ACOM-TEM; XRD; deformation mechanism; nanostructured metals; tensile testing