Segregation of Ni at early stages of radiation damage in NiCoFeCr solid solution alloys

Diffusion-mediated chemical concentration variation and void evolution in ion-irradiated NiCoFeCr high-entropy alloy

“…Numerous studies have reported consistent segregation of constituent elements around various defects, including dislocations, voids, and grain boundaries in NiCoFeCr-based HEAs after electron or ion irradiations [17,22,28,29,30]. Very recently, through the positron annihilation study, Tuomisto et al [31] demonstrated atomic level Ni segregation in irradiated NiCoFeCr under 1 dpa. However, to the best of our knowledge, no studies have reported chemical concentration change of the overall matrix in irradiated HEAs, and the chemical concentration of the matrix in irradiated HEAs is mostly considered as unchanged.…”

The dynamic evolution of swelling in nickel concentrated solid solution alloys through in situ property monitoring

“…Further evidence for the existence of nanoscale clusters in these particular compositions is provided computationally by Wang and coworkers, who predict alloys of increasing chemical complexity should retain more smaller vacancy clusters by thermodynamic analysis [46]. Experimental results from Tousmisto and coworkers on a similar selection of alloys up to quaternary compositions under room-temperature ion irradiation also show that increasing chemical complexity results in more small vacancy cluster retention using positron annhilaition spectroscopy [5]. The weaker acoustic response observed in NiFeCoCrMn in combination with the void size distribution in Fig.…”

“…This value as computed through ex situ microscopy analysis clearly fails to capture the the entire spectrum of defect morphologies which may be considered "swelling." Indeed, the literature commonly differentiates "lattice swelling" at the nanoscale [5], normally captured using X-ray diffraction [47], and "void swelling" at the mesoscale, the type of volume porosity captured here through electron microscopy, as separate effects. However, as evidenced through local elasticity, these different scales of vacancytype lattice defects impose the same fundamental changes on resulting properties.…”

“…Complex concentrated solid solution alloys (CSAs) -often classed as medium or high entropy alloys depending on their number of alloying elements -host unique intrinsic properties including local lattice distortions and sluggish heterogeneous diffusion which have prompted their study as radiation-tolerant structural materials for advanced energy applications [1,2]. A growing body of experimental and computational work dedicated to nanoscale defect diffusion [3,4], chemical segregation [5,6], and mesocale microstructure evolution [2,7] has been produced using nickel-based, single phase CSAs as a model system. Several research efforts have focused specifically on the high-damage suppression of void swelling in Ni-CSAs using ion beam irradiation and have observed a general trend of decreased swelling with increasing chemical complexity attributed to both sluggish diffusion and preferential segregation around voids and vacancy clusters [8][9][10].…”

Towards quantitative inference of nanoscale defects in irradiated metals and alloys

“…The ability of PALS to detect individual vacancies allows direct comparisons to be made to primary radiation damage simulations. Tuomisto et al [57] studied Ni-ion irradiation damage in NiCoFeCr and its derivative alloys through PALS, molecular dynamics (MD), and density functional theory (DFT) simulations, shown in Fig. 2(b).…”