Effect of Bulk Phosphorus Content on Hardening, Non-Equilibrium Segregation and Embrittlement in Neutron Irradiated Iron-Based Alloys

2000 ◽  
Vol 650 ◽  
Author(s):  
Y. Nishiyama ◽  
T. E. Bloomer ◽  
J. Kameda
Keyword(s):  
Neutron Irradiation ◽  
Thermal Aging ◽  
Irradiation Effect ◽  
Ferritic Alloys ◽  
Heat Treated ◽  
Ductile Brittle Transition Temperature ◽  
P Content ◽  
High Bulk ◽  
Mn Doped ◽  
Non Equilibrium

ABSTRACTThe effect of bulk P contents on hardening, non-equilibrium intergranular segregation and embrittlement has been studied in Mn-doped ferritic alloys subjected to neutron irradiation (E>0.1MeV: fluence of 1 × 1025 n/m2 at 711K for 2120 h) or irradiation-equivalent thermal aging. Neutron irradiation-induced intergranular P segregation became more prominent with decreasing bulk P content. Thermal aging slightly enhanced the amount of segregated P independent of the bulk P content. Intergranular C segregation in all the alloys was suppressed by the irradiation. An alloy with low bulk P content showed only moderate irradiation-induced hardening. The ductile-brittle transition temperature (DBTT) in alloys with low and intermediate amounts of P increased by the same shift during the irradiation but not at all during the thermal aging. Doping high bulk P led to a high DBTT in the as-heat-treated alloy while the irradiation decreased the DBTT. The irradiation effect on the DBTT in the model ferritic alloys containing the different levels of P is discussed in light of embrittling or toughening effects caused by the changes in the P or C segregation, and hardness.

scholarly journals On the Modelling of Thermal Aging through Neutron Irradiation and Annealing

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Boris Margolin ◽  
Elena Yurchenko ◽  
Vera Potapova ◽  
Valery Pechenkin
Keyword(s):  
Impact Strength ◽  
Neutron Irradiation ◽  
Thermal Aging ◽  
Tensile Tests ◽  
Pressure Vessels ◽  
Irradiation Effect ◽  
Thermal Embrittlement ◽  
P Diffusion ◽  
Material Conditions

A new method predicting long-term thermal embrittlement of steel caused by P segregation is verified. The method is based on the results of impact strength or fracture toughness tests using specimens after relatively short-term neutron irradiation followed by annealing. 2Cr–Ni–Mo–V steel used in reactor pressure vessels of WWER-1000 type is investigated in four conditions: initial condition, after thermal aging, after neutron irradiation, and postirradiation annealing. The results of impact strength and tensile tests and SEM investigation are presented. The brittle fracture features are considered for different material conditions. Calculative estimation on neutron irradiation effect on P diffusion in steels is carried out. Experimental data are reported which confirm an intense P diffusion acceleration under neutron irradiation.

Non-equilibrium intergranular segregation and embrittlement in neutron-irradiated ferritic alloys

2001 ◽  
Vol 31 (7) ◽  
pp. 522-531 ◽  
Author(s):  
J. Kameda ◽  
Y. Nishiyama ◽  
T. E. Bloomer
Keyword(s):  
Ferritic Alloys ◽  
Non Equilibrium

scholarly journals Stability Improvement of Flexible Shallow Shells Using Neutron Radiation

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3187
Author(s):  
Anton V. Krysko ◽  
Jan Awrejcewicz ◽  
Irina V. Papkova ◽  
Vadim A. Krysko
Keyword(s):  
Temperature Field ◽  
Neutron Irradiation ◽  
Microelectromechanical Systems ◽  
Neutron Radiation ◽  
Middle Surface ◽  
Aviation Industry ◽  
Irradiation Effect ◽  
Structural Members ◽  
Mems Devices ◽  
Shallow Shells

Microelectromechanical systems (MEMS) are increasingly playing a significant role in the aviation industry and space exploration. Moreover, there is a need to study the neutron radiation effect on the MEMS structural members and the MEMS devices reliability in general. Experiments with MEMS structural members showed changes in their operation after exposure to neutron radiation. In this study, the neutron irradiation effect on the flexible MEMS resonators’ stability in the form of shallow rectangular shells is investigated. The theory of flexible rectangular shallow shells under the influence of both neutron irradiation and temperature field is developed. It consists of three components. First, the theory of flexible rectangular shallow shells under neutron radiation in temperature field was considered based on the Kirchhoff hypothesis and energetic Hamilton principle. Second, the theory of plasticity relaxation and cyclic loading were taken into account. Third, the Birger method of variable parameters was employed. The derived mathematical model was solved using both the finite difference method and the Bubnov–Galerkin method of higher approximations. It was established based on a few numeric examples that the irradiation direction of the MEMS structural members significantly affects the magnitude and shape of the plastic deformations’ distribution, as well as the forces magnitude in the shell middle surface, although qualitatively with the same deflection the diagrams of the main investigated functions were similar.

Effects of Neutron Irradiation and Thermal Aging on Mechanical Properties of ODS Ferritic Steels for Advanced Nuclear Systems

2007 ◽  
Vol 561-565 ◽  
pp. 1773-1776 ◽  
Author(s):  
Ryuta Kasada ◽  
Hang Sik Cho ◽  
Naoyuki Okuda ◽  
Akihiko Kimura
Keyword(s):  
Neutron Irradiation ◽  
Thermal Aging ◽  
Charpy Impact ◽  
Oxide Dispersion Strengthened ◽  
Tensile Tests ◽  
Total Elongation ◽  
Ferritic Steels ◽  
Dislocation Loops ◽  
Irradiation Hardening ◽  
Nuclear Systems

Effects of neutron irradiation and thermal aging on the tensile properties and Charpy impact properties of oxide dispersion strengthened (ODS) ferritic steels for advanced nuclear systems were investigated and discussed with the results of microstructural observation. After the neutron irradiation in JMTR, significant hardening after irradiation at 290 and 400 °C as well as thermal aging at 500 °C, while no effect was observed after irradiation at 600 °C. While the irradiation hardening was not accompanied by a reduction of total elongation in tensile tests, Charpy impact energy at room temperature was reduced after the irradiation. The hardening after the irradiation at 400 °C and the aging at 500 °C was probably due to the formation of Cr-rich phases. The irradiation hardening observed in the ODS ferritic steels irradiated at 290 °C was well explained by the formation of dislocation loops.

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