Positron annihilation studies in plastically deformed Fe‐Mn‐Si‐Cr‐Ni‐C

Abstract

AbstractFe‐Mn‐Si‐Cr‐Ni‐C samples with deformations from 2 to 20% were investigated using positron annihilation spectroscopy, optical microscopy (OM) and X‐ray diffraction (XRD). Both Doppler broadening of the annihilation radiation (DBAR) and positron annihilation lifetime spectroscopy (PALS) measurements were performed. The DBAR experiments, carried out using a slow positron beam, indicate a sudden increase in the defect concentration in between 4 and 6% deformation. This is confirmed by the lifetime measurements. In between 6% and 8% deformation the lineshape parameter significantly changes which coincides with the drastic increase of the concentration of the martensite phase as confirmed by XRD. Positron annihilation spectroscopy indirectly probe the γ/ε martensitic phase transformation by probing correlated dislocations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)