Abstract
The relationship among tensile strength, Vickers hardness and dislocation density for two types of 11Cr-ferritic/martensitic steel (PNC-FMS) was investigated after aging at temperatures between 400 and 800°C up to 45,000h and after neutron irradiation. A correlation between tensile strength and Vickers hardness was expressed empirically. The linear relationship for PNC-FMS wrapper material was observed between yield stress and the square of dislocation density at RT and aging temperature according to Bailey–Hirsch relation. Therefore, it was clarified that the correlation among dislocation density, tensile strength and Vickers hardness to aging temperature was in good agreement. On the other hand, the relationship between tensile strength ratio when materials were tested at aging temperature and Larson–Miller parameter was also in excellent agreement with aging data between 400 and 700°C. It was suggested that this correlation could use quantitatively for separately evaluating irradiation effects from neutron irradiation data containing both irradiation and aging effects.
Highlights
The ferritic/martensitic (F/M) steels are expected to be used for the long life core material of fast reactors (FRs) and for the blanket materials of fusion reactors because of their superior swelling resistance
It was clarified that the correlation among dislocation density, tensile strength and Vickers hardness was in good agreement and that Micro-Vickers hardness tests were useful as a quantitative measure of mechanical and microstructural properties in materials of different heat-treatments after aging and after irradiation
It was suggested that the difference between this and the previous study would be attributed to both the number of data accumulated and no data for Tensile tests, Vickers hardness tests and dislocation density measurements of two types of aged PNC-FMS were conducted at room temperature (RT) to investigate the influence of different heat-treatments on the effective utilization of the materials
Summary
The ferritic/martensitic (F/M) steels are expected to be used for the long life core material of fast reactors (FRs) and for the blanket materials of fusion reactors because of their superior swelling resistance. Two types of 11Cr-F/M steel (PNC-FMS) have been developed in the Japan Atomic Energy Agency as materials for wrapper tubes and cladding tubes for use in the Japanese Sodium-cooled FR (JSFR) [1,2,3,4,5] These wrapper and cladding materials have the same range of elemental compositions, but their final heat treatments are different. Uehira et al [1] examined tensile properties of PNC-FMS cladding and wrapper materials after accelerating aging at 410–750 °C up to 10,000 h They reported that tensile properties of two heats at the same aging temperatures were quite different These previous studies [1, 6,7] have provided fundamental knowledge that irradiation and thermal aging behavior of F/M steels in different heat-treatments were different and identical evaluations were difficult. Wrapper: normalized at 1050 °C for 40 min and tempered at 710 °C for 40 min Cladding: normalized at 1100 °C for 10 min and tempered at 780 °C for 60 min
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
