Mikrostrukturentwicklung bei zyklischer Hochverformung

Translated title of the contribution: Microstructure Evolution by Cyclic Severe Plastic Deformation

Christian Rupert Rehrl

Research output: ThesisDiploma Thesis


The aim of the work was to investigate the influence of cyclic severe plastic deformation (SPD) at technically relevant deformation temperatures on the decrease of grain size and the developed grain structure. The tested soft magnetic Fe-Co-alloy is used in direct-injection systems in the automotive industry. The deformation behaviour was characterized by compression tests in the temperature range of 450 °C to 800 °C. As SPD methods the multiaxial deformation and the cyclic High Pressure Torsion were used. The evolution of the microstructure was investigated by means of scanning electron microscopy using backscattered electrons and electron backscatter diffraction (EBSD). From the EBSD orientation data Inverse Pole Figures and Unique Grain Color maps were generated and the missorientation-distributions were calculated. For both deformation methods a typical inhomogeneity in deformation was found. The two procedures are efficient methods to decrease the grain size. The coarse initial grain size was refined by SPD at 450 °C to a ultra fine crystalline microstructure. Concerning the effectiveness of the deformation it was shown that low deformation-temperature, high strain rate and high accumulated strain with high cyclic strain leads to a finer and more homogeneous microstructure. For higher accumulated strain the material exhibits a saturation in grain size.
Translated title of the contributionMicrostructure Evolution by Cyclic Severe Plastic Deformation
Original languageGerman
  • Pippan, Reinhard, Supervisor (internal)
  • Kleber, Siegfried, Co-Supervisor (external), External person
Award date15 Dec 2006
Publication statusPublished - 2006

Bibliographical note

embargoed until null


  • severe plastic deformation High Pressure Torsion
  • cyclic multiaxial deformation compression test missorientation distribution microstructure
  • ultra fine crystalline

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