Pearlitic steels

6.3 GPa hypereutectoid pearlitic steel
This work is about a better understanding of the evolution of strength and microstructure during annealing of heavily cold-drawn 6.3 GPa hypereutectoid pearlitic steel wire
Acta mater Vol 60 2012-heat treated pear[...]
PDF-Dokument [2.7 MB]
Thermodynamics of carbon solubility in ferrite and vacancy formation in cementite in strained pearlite
In order to investigate the thermodynamic driving force for the experimentally observed accumulation of C in ferritic layers of severely plastically deformed pearlitic wires, the stabilities of C inte
Acta Mater 61 (2013) 1773-solute-C-in-pe[...]
PDF-Dokument [1.0 MB]
Atomic-scale mechanisms of deformation-induced cementite decomposition in pearlite
Pearlitic steel can exhibit tensile strengths higher than 5 GPa after severe plastic deformation, where the deformation promotes a refinement of the lamellar structure and cementite decomposition. How
PDF-Dokument [2.8 MB]
Mechanisms of subgrain coarsening and its effect on the mechanical properties of carbon-supersaturated nanocrystalline hypereutectoid steel
Carbon-supersaturated nanocrystalline hypereutectoid steels with a tensile strength of 6.35 GPa were produced from severely cold-drawn pearlite. The nanocrystalline material undergoes softening upon annealing at temperatures between 200 and 450°C. The ductility in terms of elongation to failure exhibits a non-monotonic dependence on temperature. Here, the icrostructural mechanisms responsible for changes in the mechanical properties were studied using transmission electron microscopy (TEM), TEM-based automated scanning nanobeam diffraction and atom probe tomography (APT).
Acta Materialia 84 (2015) 110-123 atom p[...]
PDF-Dokument [2.4 MB]
Segregation Stabilizes Nanocrystalline Bulk Steel with Near Theoretical Strength
Grain refinement through severe plastic deformation enables synthesis of ultrahigh-strength nanostructured materials. Two challenges exist in that context: First, deformation-driven grain refinement is limited by dynamic dislocation recovery and crystal coarsening due to capillary driving forces; second, grain boundary sliding and hence softening occur when the grain size approaches several nanometers. Here, both challenges have been overcome by severe drawing of a pearlitic steel wire (pearlite: lamellar structure of alternating iron and iron carbide layers).
Li and Raabe Phys Rev Lett vol 113 page [...]
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Atomic-Scale Quantification of Grain Boundary Segregation in Nanocrystalline Material
Grain boundary segregation leads to nanoscale chemical variations that can alter a material's performance by orders ofmagnitude (e.g., embrittlement). To understand this phenomenon, a large number of grain boundaries must be characterized in terms of both their five crystallographic interface parameters and their atomic-scale chemical composition. We demonstrate how this can be achieved using an approach that combines the accuracy of structural characterization in transmission electron microscopy with the 3D chemical sensitivity of atom probe tomography.
Phys Rev Lett. 2014 grain boundary segre[...]
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