Critical assessment of low fluence irradiation creep mechanisms
A modified climb-controlled glide (CCG) creep model, which had been used to successfully rationalize low-dose, light-ion irradiation creep data in pure nickel, accounted for low-fluence irradiation creep rates and loop growth rates in 316 stainless steel. The model also predicted a weak stress dependence and a weak temperature dependence in agreement with typical observations. Both light ion and neutron irradiation creep measurements and microstructural observations at low doses were examined and compared with predictions of the CCG model. Calculated creep rates compared to measured creep rates demonstrated that dislocation glide was the dominant mode of deformation during low dose creep when interstitial loops were small. When the interstitial loop radius approached one-half the average dislocation glide distance, the dislocation glide contribution was small. The stress induced preferred absorption (SIPA) creep mechanism contributed an increasing fraction of the total deformation as the loop radius increased and became dominant at high fluences. The modified CCG creep model assumes that glissile network dislocation intersect the small dislocation loop glide barriers, climb into a favorable orientation and annihilate the loop via a Burgers vector reaction. Dislocation climb controls the rate of loop annihilation that allows dislocation glide between loop barriers. The creep rate is determined by a balance between irradiation enhanced dislocation climb and interstitial loop growth.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (USA)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 6678354
- Report Number(s):
- PNL-SA-12098; CONF-840604-17; ON: DE84015578
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360106* -- Metals & Alloys-- Radiation Effects
ALLOYS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
CREEP
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISLOCATIONS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
KINETICS
LINE DEFECTS
MATERIALS
MECHANICAL PROPERTIES
MOLYBDENUM ALLOYS
NICKEL ALLOYS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
STAINLESS STEEL-316
STAINLESS STEELS
STEELS