Mechanism of Radiation Damage Reduction in Equiatomic Multicomponent Single Phase Alloys

Abstract

Recently a new class of metal alloys, of single-phase multicomponent composition at roughly equal atomic concentrations ("equiatomic"), have been shown to exhibit promising mechanical, magnetic, and corrosion resistance properties, in particular, at high temperatures. These features make them potential candidates for components of next-generation nuclear reactors and other high-radiation environments that will involve high temperatures combined with corrosive environments and extreme radiation exposure. In spite of a wide range of recent studies of many important properties of these alloys, their radiation tolerance at high doses remains unexplored. In this work, a combination of experimental and modeling efforts reveals a substantial reduction of damage accumulation under prolonged irradiation in single-phase NiFe and NiCoCr alloys compared to elemental Ni. This effect is explained by reduced dislocation mobility, which leads to slower growth of large dislocation structures. Moreover, there is no observable phase separation, ordering, or amorphization, pointing to a high phase stability of this class of alloys.

The effect of alloying nickel with iron on the supersonic ballistic stage of high energy displacement cascades

“…The latter case has shown little differences in defect production and defect cluster size. In contrast with the FeCr case, recent studies in concentrated solid solutions (NiFe [13,14,2,15,16], NiCr [16], NiCo [2,15], and NiCoCr [17]) indicate that such alloying has an important effect on both the number of stable defect produced and the distribution of defect clusters. Understanding the physical processes dictating the radiation response in these materials is an important step towards a better understanding of the high-entropy alloys that are composed of the same elements as these binary and ternary alloys.…”

Single-Phase Concentrated Solid-Solution Alloys: Bridging Intrinsic Transport Properties and Irradiation Resistance

“…NiCoFeCr and its SP-CSA subsets in single crystalline form have been experimentally studied in response to Au and Ni ion irradiations at room temperature (Zhang et al, 2015Granberg et al, 2016;Jin et al, 2016a,b;Lu et al, 2016a;Velişa et al, 2017a). All the studied alloys have shown lower overall lattice distortion compared with pure Ni in the relatively low dose regime, as characterized using ion channeling techniques.…”

Enhancing radiation tolerance by controlling defect mobility and migration pathways in multicomponent single-phase alloys

“…In addition, the high-level site-to-site lattice distortions and compositional complexities in SP-CSAs can effectively reduce the mean free path of electrons, phonons and magnons; these distortions and complexities can also be used to modify formation energies, migration barriers and diffusion pathways of irradiation-induced defects, thereby modifying defect generation, interaction, interstitial–vacancy recombination in the early stages of irradiation17181920. A recently published paper indicates that equiatomic alloys may be more resistant to radiation damage than the corresponding pure elements21. To obtain a full picture of the fundamental controlling mechanism on enhanced radiation tolerance, partly due to the development of defect clusters at elevated temperature and high irradiation doses, a set of SP-CSAs with different alloying elements needs to be investigated.…”