Among new prospective materials multi-principal element alloys (MPEA) have attracted considerable attention in recent years due to their excellent corrosion and irradiation resistance as well as their good mechanical properties over a wide temperature range. The new lightweight multi-principal element titanium-based alloy 61Ti-10Cr-7Al11V-11Nb (at. %) with high ductility at room and elevated temperatures is studied. This single-phase bcc alloy was irradiated with 1.4 MeV Ar ions at room temperature and mid-range doses from 1 to 10 displacements per atom. The effect of irradiation is studied by examining the hardening. A comparison was performed with irradiation-induced hardening behaviour of MPEA, 316 austenitic stainless steel irradiated under an identical condition. It was shown that hardness increases with irradiation dose for all the materials studied, but this increase is lower in multi-principal element alloys both face-centered cubic (FCC) and body-centered cubic (BCC) structures than in stainless conventional steel.

Nanocrystalline porous VNx films obtained by ion-beam assisted deposition of vanadium on silicon substrates were investigated in this work. The influence of deposition time and film thickness on the regularities of the formation of nanoporosity was studied by means of high-resolution electron microscopy. It is shown that the combined effect of radiation defects and gas impurities leads to the formation of an open intergranular nanoporosity. VNx films comprise 150-250 nm-particles separated by porous boundaries 4-8 nm thick. The nano-particles, in turn, are composed of 15-20 nm-grains. The structure, composition and formation mechanism of the mixing zones were also studied. It was revealed that these non-uniform zones contain areas of vanadium and silicon nitrides with different types of structure. According to the Rutherford backscattering data and profilo-metry measurements, VNx film porosity was 27%. Due to its structural features, the thin films obtained by ion-beam assisted deposition can be considered as a promising material for hydrogen storage.

The initial stages of formation of VN–Ar/He nanocrystalline thin films that were obtained using ion beam-assisted deposition technology have been investigated. It has been shown that the vanadium deposition accompanied by mixed inert and reactive gas beam bombardment leads to the formation of a nanoporous structure. The electron microscopic data and computer simulation results prove that many different processes take place during film structure nucleation, in particular, metal atom deposition, gas–vacancy cluster formation, and their migration, growth and collapse with gas release. As a result, vacant and gas-filled pores with a diameter of 5–50 nm were created.

Vacancy voids have been produced in Ni by 1.2MeV Cr ion irradiation at 873K up to the ion fluence of 1021m−2. Subsequent irradiation of specimens containing voids at 798 and 723K has resulted in the reduction of the void size and number density. Accordingly, the void swelling has decreased by a factor of ∼5. The experimental results are explained in the framework of an original model taking into account the interaction of voids with radiation-induced excitations of atomic structure such as focusing collisions and long-propagating self-focusing breathers.

One of peculiar features of the IBAD technology consists in that the damage level and concentration of implanted ions are distributed nonuniformly in the depth of deposited material. The calculations, we have done earlier [1], showed that the highest degree of nonequilibrium is realized in the first 50 nm of a coating. However, just in this thickness the nucleation and formation of the material structure is observed. The peculiarities of chromium coating formation without assisted irradiation and under bombarding with nitrogen ions having the energy of 30 keV were studied. The rates of chromium deposition were low, 0,05...0,1 nm/s. During the experiment the vacuum was maintained at a level of 4.10(3 )Pa and was determined, in main, by the content of nitrogen molecules arriving from the discharging chamber of the ion source. The thickness within the range from 3 to 10 nm was investigated. The results have shown that at the earliest stages of the film growth solely chromium nitride CrN is formed. Sizes of visible nuclei are in the range from 1 to 4 nm, and their density is 1...3.10(12)cm(-2). As the film thickness increases, the nuclei are growing, then their coalescence occurs and a uniform coating is formed. Chromium deposition without irradiation, but at the same nitrogen pressure, resulted in formation of chromium hcp structure with the following crystallographic parameters: a = 0,315 rim; c = 0,492 nm. The grain size was 3...4 rim. After reaching the coating continuity, the hcp structure was transformed into the bcc structure with the parameter a = 0,261 nm.