Fe~+ Implantation Induced Damage in Oxide Dispersion Strengthened Steels Investigated by Doppler Broadening Spectroscopy

摘要

Open volume defects created by 1 MeV Fe~+ implantation up to a damage of 15 displacements per atom into Fel4wt%Cr and into oxide dispersion strengthened (ODS) Fe14wt%Cr were investigated by positron annihilation spectroscopy, especially single Doppler broadening (DBS) and coincidence Doppler broadening spectroscopies (cDBS). The influence of W and Ti alloying elements on the evolution of defects during ion implantation were probed in addition. Whereas no effect of the W and Ti alloying constituents on the line-shape parameters S and W could be detected both before and after ion implantation, fine dispersed Y2O3 particles showed important changes in the structural properties compared to pure FeCr steel, which could be detected by DBS and cDBS. The distribution of the electron momenta in implanted ODS Fe14Cr, obtained with cDBS, shows that oxide particles form obstacles for expanded vacancy mobility and that the vacancies are localized around the oxide particles.