铁素体-马氏体钢中辐射诱导析出物及其抗辐照效应

Abstract

<p>Designing high-performance radiation-tolerant materials and understanding the atomistic mechanism of radiation <span>resistance are important topics in nuclear energy structural materials research. In this study, we investigated </span><span>the atomistic mechanism of the formation of rod-like precipitates in helium-irradiated ferritic-martensitic steels </span><span>(F-M steels) by positron annihilation spectroscopy (PAS) and transmission electron microscopy with energy </span><span>dispersive X-ray spectroscopy (TEM/EDX). The results indicated that vacancies tended to accumulate near </span><span>dislocation lines to form complexes in the reduced activation ferritic-martensitic (RAFM) steel. Moreover, Fe and </span><span>Cr atoms diffused toward these complexes and eventually depleted therein, which was not conducive to the </span><span>formation of rod-like precipitates. Conversely, impurity atoms such as C atoms were found to segregate near </span><span>dislocations in the Y-bearing oxide dispersion strengthened (Y-ODS) steel. When Fe and Cr diffused toward </span><span>dislocations, they exchanged positions with C atoms until Fe and Cr exceeded their saturation solubilities and </span><span>precipitated on the glide plane. We also analyzed the distribution of vacancy defects and bubbles/voids in the </span><span>four irradiated materials and discussed the radiation resistance mechanism of the precipitates. The results of this </span><span>study are significant in demonstrating a microscopic mechanism of radiation-induced precipitates to swelling </span><span>resistance in materials.</span></p>