The influence of ion beam rastering on the swelling of self-ion irradiated pure iron at 450 °C

Abstract

2016-11-02T18:49:00

Use of double and triple-ion irradiation to study the influence of high levels of helium and hydrogen on void swelling of 8–12% Cr ferritic-martensitic steels

“…The irradiation proceeded using a steady-beam, non-rastering approach in order to be compliant with ASTM standard E521-83, ''Standard Practice for Neutron Radiation Damage Simulation by Charged-Particle Irradiation'' that states, ''It is recommended that a rastered beam be avoided for the simulation of a constant neutron flux.'' [37] Beam rastering has recently been shown to strongly suppress swelling in both pure iron and in HT9 from the swelling observed in a defocused non-rastered irradiation [38][39].…”

Microstructural changes and void swelling of a 12Cr ODS ferritic-martensitic alloy after high-dpa self-ion irradiation

“…To date, however, very limited results have been reported on ODS tempered martensite phase [7-9, 20, 21]. Among them, a 9Cr ODS tempered martensite alloy was reported to have promising swelling resistance, improved strength, but exhibited complicated dispersoid dissolution behavior under irradiation using a rastered ion beam [7][8][9]20], in spite of the fact that beam rastering is known to suppress void nucleation and growth [22][23][24].…”

“…In this work, microstructures of this 12Cr dual-phase ODS were characterized before and after ion irradiation to very high displacements per atom (dpa) values using a defocused non-rastered beam. Defocusing beams were used since they better resemble reactor neutron damage, compared to pulsed beams that suppress void swelling [23,24]. The radiation response of dispersoids in both ferrite and tempered martensite were studied separately, providing information to guide the next steps of material development toward a stronger radiation tolerance of F/M alloys.…”

Monte Carlo modeling of cavity imaging in pure iron using back-scatter electron scanning microscopy

“…Since its first observation in 1967 [4], neutron-induced void swelling in stainless steels especially has been a subject of intensive research, as swelling leads to significant dimensional instabilities via swelling and irradiation creep, with concurrent changes in mechanical and physical properties and also in new modes of embrittlement [2][3][4][5][6][7][8]. Swelling and bubble formation (both hereafter referred to as cavities) induced by charged particle irradiation is also being increasingly studied as a surrogate for neutron irradiation [9][10][11][12][13][14][15][16][17][18].Void swelling is caused by incomplete interstitial-vacancy recombination and biased defect-sink interactions during displacive irradiation by neutrons or charged particles, and its general dependence on damage dose defined in displacements per atom (dpa), dpa rate, temperature, and stress are relatively well known [1][2][3].…”

“…inducing positive charges on the top of cavities and negative charges at the bottom of cavities. Such charging will dramatically distort BSE and SE yields for the detector[9].…”