Effects of 3d electron configurations on helium bubble formation and void swelling in concentrated solid-solution alloys

Abstract

Elemental specific chemical complexity is known to play a critical role in microstructure development in single-phase concentrated solid-solution alloys (SP-CSAs), including both He bubble formation and irradiation-induced void swelling. While cavity formation and evolution under ion irradiation at elevated temperature are complex nonequilibrium processes, chemical effects are revealed at the level of electrons and atoms herein in a simplified picture, using Ni and a special set of Ni-based SP-CSAs composed of 3d transition metals as model alloys. Based on Ni and model alloys with minimized variables (e.g., atomic mass, size, and lattice structure), we discuss the effects of chemically-biased energy dissipation, defect energetics, sluggish diffusion, and atomic transport on cavity formation and evolution under both self-ion Ni irradiation and He implantation. The observed difference in microstructure evolution is attributed to the effects of d electron interactions in their integrated ability to dissipate radiation energy. The demonstrated impact of alloying 3d transition metals with larger differences in the outermost electron counts suggests a simple design strategy of tuning defect properties for improved radiation tolerance in structural alloys.

Study of the Application Efficiency of Irradiation with Heavy Ions to Increase the Helium Swelling Resistance of BeO Ceramics

“…At the same time, the shape of diffraction lines and the ratio of diffraction reflections and background radiation areas, as obtained by approximation with pseudo-Voigt functions of the obtained diffraction patterns, indicate a high structural ordering degree (more than 98%). The crystal lattice parameters of the samples in the initial state were a = 2.6699 Å and c = 4.3369 Å, and the crystal lattice volume was 26.77 Å 3 .…”

“…As is known, one of the key problems in the use of structural materials in nuclear power, including high-temperature reactors, is the problem of the transmutation helium accumulation and the subsequent gas swelling of the near-surface layer of protective materials or materials of inert matrices [1][2][3]. These processes are based on the high mobility of the implanted helium in the structure and its poor solubility, which leads to the fact that gas-filled regions in the structure of the material can be formed at high accumulated-helium concentrations.…”

Theoretical Combined Experimental Study of Unique He Behaviors in High-Entropy Alloys

“…, neutrons and ions). Experimentally, Zhang et al conducted He implantations in concentrated solid-solution alloys at 773 K to investigate He bubble formation. Hence, in this study, the temperature of 800 K is chosen for AIMD simulations.…”

Tunable chemical complexity to control atomic diffusion in alloys

“…Theoretical and experimental efforts have been undertaken to understand the mechanisms that control alloy properties. Mixing enthalpy 9,10 , defect energetics [11][12][13] , local lattice distortions [13][14][15] , stresses and pressure [16][17][18] , electronic 13,19 and magnetic state disorder 20 were studied. While certain correlations were observed between these properties and alloys performance, clear and predictive models were not developed.…”

“…By cross-verifying theory and kMC results, the local formation energy of migrating defects is revealed to be the parameter controlling the atomic transport. While mixing enthalpy, defect energetics, local lattice distortion, electronic characteristics and magnetic frustration are reported as unique features in CSAs [9][10][11][12][13][14][15][16][17][18][19] , this parameter is proposed as the measure of chemical complexity of the alloys for their observed difference in defect evolution and radiation tolerance 13 .…”