Advanced Study Group Ab Initio Based Modelling (ABM)
Tetragonal fcc-Fe induced by kappa-carbide precipitates: Atomic scale insights from correlative electron microscopy, atom probe tomography, and density functional theory
C. Liebscher, M. Yao, P. Dey, M. Lipinska-Chwalek, B. Berkels, B. Gault, T. Hickel, M. Herbig, J. Mayer, J. Neugebauer, D. Raabe, G. Dehm, C. Scheu.
Physiacal Review Materials, 2, 023804, (2018)
Correlative scanning transmission electron microscopy, atom probe tomography, and density functional theory calculations resolve the correlation between elastic strain fields and local impurity concentrations on the atomic scale. The correlative approach is applied to coherent interfaces in a κ-carbide strengthened low-density steel and establishes a tetragonal distortion of fcc-Fe. An interfacial roughness of∼1nm and a localized carbon concentration gradient extending over∼2–3nm is revealed, which originates from the mechano-chemical coupling between local strain and composition.
Keyword(s): crystal structure; alloys; solid-solid interfaces; density functional theory; first-principles calculations; high-resolution transmission electron microscopy