TY - JOUR

T1 - Anisotropic deformation characteristics of an ultrafine- and nanolamellar pearlitic steel

AU - Kapp, Marlene

AU - Hohenwarter, Anton

AU - Wurster, Stefan

AU - Yang, Bo

AU - Pippan, Reinhard

PY - 2016/1/21

Y1 - 2016/1/21

N2 - Micromechanical experiments with 3 × 3 × 6 μm3 sized micro pillars were used to examine orientation dependencies of the mechanical properties in a severely plastically deformed high strength steel and compared with the undeformed state. For the synthesis, an initially ultrafine-lamellar (UFL) fully pearlitic steel was subjected to high pressure torsion (HPT) transforming the steel into a nanolamellar (NL) composite. Both microstructural states were then tested in-situ inside a scanning electron microscope. Within the individual micro pillars, fabricated by focused ion beam milling, the ferrite and cementite lamellae were aligned parallel, normal or inclined to the loading direction. The main findings are: First, the strength and strain hardening capacity is more than doubled comparing the UFL with the NL composite. Second, an anisotropic mechanical response exists in terms of i) strain hardening capacity and ii) stress level at the onset of plateau formation. Third, deformation and localization mechanisms at large compressive strains vary with the lamellae orientation, however they are independent of the lamellae thickness.

AB - Micromechanical experiments with 3 × 3 × 6 μm3 sized micro pillars were used to examine orientation dependencies of the mechanical properties in a severely plastically deformed high strength steel and compared with the undeformed state. For the synthesis, an initially ultrafine-lamellar (UFL) fully pearlitic steel was subjected to high pressure torsion (HPT) transforming the steel into a nanolamellar (NL) composite. Both microstructural states were then tested in-situ inside a scanning electron microscope. Within the individual micro pillars, fabricated by focused ion beam milling, the ferrite and cementite lamellae were aligned parallel, normal or inclined to the loading direction. The main findings are: First, the strength and strain hardening capacity is more than doubled comparing the UFL with the NL composite. Second, an anisotropic mechanical response exists in terms of i) strain hardening capacity and ii) stress level at the onset of plateau formation. Third, deformation and localization mechanisms at large compressive strains vary with the lamellae orientation, however they are independent of the lamellae thickness.

KW - High pressure torsion

KW - Mechanical behavior

KW - Micro compression

KW - Nanocomposite

KW - Strength

UR - http://www.scopus.com/inward/record.url?scp=84956981588&partnerID=8YFLogxK

U2 - 10.1016/j.actamat.2015.12.037

DO - 10.1016/j.actamat.2015.12.037

M3 - Article

AN - SCOPUS:84956981588

VL - 106.2016

SP - 239

EP - 248

JO - Acta materialia

JF - Acta materialia

SN - 1359-6454

IS - March

ER -