Microstructural evolution of RPV steels under proton and ion irradiation studied by positron annihilation spectroscopy

作者：Jiang, J.; Wu, Y. C.^*; Liu, X. B.; Wang, R. S.; Nagai, Y.; Inoue, K.; Shimizu, Y.; Toyama, T.

来源：Journal of Nuclear Materials, 2015, 458: 326-334.

DOI：10.1016/j.jnucmat.2014.12.113

• PRESSURE-VESSEL STEEL
• ATOM-PROBE TOMOGRAPHY
• MODEL ALLOYS
• NEUTRON-IRRADIATION
• NANOSTRUCTURAL EVOLUTION
• DEFECT ACCUMULATION
• A533B STEEL
• HIGH-NICKEL
• EMBRITTLEMENT
• FE

The microstructural evolution of reactor pressure vessel (RPV) steels induced by proton and heavy ion irradiation at low temperature (similar to 373 K) has been investigated using positron annihilation spectroscopy (PAS), atom probe tomography (APT), transmission electron microscopy (TEM) and nanoindentation. The PAS results indicated that both proton and heavy ion irradiation produce a large number of matrix defects, which contain small-size defects such as vacancies, vacancy-solute complexes, dislocation loops, and large-size vacancy clusters. In proton irradiated RPV steels, the size and number density of vacancy cluster defects increased rapidly with increasing dose due to the migration and agglomeration of vacancies. In contrast, for Fe ion irradiated steels, high density, larger size vacancy clusters can be easily induced at low dose, showing saturation in PAS response with increasing dose. No clear precipitates, solute-enriched clusters or other forms of solute segregation were observed by APT. Furthermore, dislocation loops were observed by TEM after 1.0 dpa, 240 keV proton irradiation, and an increase of the average nanoindentation hardness was found. It is suggested that ion irradiation produces many point defects and vacancy cluster defects, which induce the formation of dislocation loops and the increase of nanoindentation hardness.

• 出版日期2015-3
• 单位武汉大学