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The article presents the results of research on the effect of 160 MeV xenon ions irradiation on the mechanical and tribological properties of the Nimonic 90 superalloy. The alloy samples were irradiated with xenon ion fluences ranging from 1 × 1014 to 5 × 1014 Xe24+/cm2 at a temperature of 60 °C. The investigations revealed significant changes in the crystal structure of the material, including the formation of new phases and partial amorphisation of the surface layer, particularly pronounced at the highest irradiation fluence. Measurements of microhardness, coefficient of friction, and wear revealed a deterioration in the mechanical and tribological properties of the samples irradiated with fluences of 1.0 and 2.5 × 1014 Xe24+ ions/cm2, attributed to the formation of radiation-induced defects. Increased friction and wear were observed at depths greater than the predicted range of xenon ions, indicating the occurrence of a long-range effect. After irradiation with a 5.0 × 1014 Xe24+ ions/cm2 fluence, a radiation annealing effect was observed, leading to a partial reduction in the earlier damage and resulting in improved microhardness and reduced wear. To our knowledge, this is the first observation of a radiation annealing effect under these specific irradiation and test conditions. The findings suggest limitations in the application of the Nimonic 90 superalloy in environments exposed to intense ionizing radiation, such as nuclear reactors.

Nanoparticles of manganese ferrite were obtained by the impregnation of highly ordered mesoporous MCM-41 silica support. The investigated sample contained 20% wt. Fe. The obtained nanocrystallites were strongly dispersed in silica matrix and their size was about 2 nm. The sample annealing at 500°C led to increase of particle size to about 5 nm. The Mössbauer spectroscopy investigations performed at room temperature show on occurrence of MnFe nanoparticle in superparamagnetic state for the sample annealed in all temperatures. The coexistence of superparamagnetic and ferromagnetic phase was observed at liquid nitrogen temperature. The sample annealed at 400°C and 500°C has bigger manganese ferrite particle and better crystallized structure. One can assign them the discrete hyperfine magnetic field components.

In this paper, results of positron annihilation lifetime spectroscopy (PALS) studies of MnFe /MCM-41 nanocomposites in N and O atmosphere have been presented. In particular, the influence of manganese ferrite loading and gas filling on -positronium ( -Ps) annihilation processes in the investigated samples was a point of interest. Disappearance of the longest-lived -Ps component with τ present in the PAL spectrum of initial MCM-41 mesoporous material in the PAL spectra of MnFe -impregnated MCM-41 measured in vacuum is a result of either a strong chemical -Ps quenching or the Ps inhibition effects. The intensity of the medium-lived component initially increases, reaching a maximum value for the sample with minimum manganese ferrite content, and then decreases monotonically. Analogous dependence for the intensity of the shortest-lived component shows a maximum at higher MnFe content. Filling of open pores present in the studied nanocomposites by N or O at ambient pressure causes partial reappearance of the τ and τ components, except a sample with maximum ferrite content. The lifetimes of these components measured in O are shortened in comparison to that observed in N because of paramagnetic quenching. Anti-inhibition and anti-quenching effects of atmospheric gases observed in the MnFe /MCM-41 samples are a result of neutralization of some surface active centers acting as inhibitors and weakening of annihilation mechanism, respectively.

The aim of the presented paper is to study an influence of replacement of Fe atoms by Si atoms in quasibinary Sc(Fe Si Laves phases on their structural and magnetic properties. Powder X-ray diffraction (XRD) and neutron diffraction (ND) measurements carried out at different temperatures from 4.3 K up to about 700 K revealed that samples were single phase with cubic 15 structure for Si concentration from 0.05 to 0.20 and hexagonal 14 structure for higher concentration. The results of Fe Mössbauer measurements showed that the Sc(Fe Si compounds with ≤ 0.30 are ferrimagnetic at 4.3 K. At temperature 80 K in the samples with = 0.20 and 0.30, a magnetic cluster spin-glass state has been observed, as ferrimagnetic long-range order disappears. Such picture was supported by the results of ND measurements carried out at 8 K, which confirmed the lack of long-range order for above 0.10 and an occurrence of hyperfine field distributions in the corresponding Mössbauer spectra. At room temperature, samples with ≥ 0.20 became paramagnetic. A substitution of Si atoms for Fe ones leads to a decreasing of mean values of hyperfine magnetic fields in samples under investigation. From the neutron diffraction pattern analysis of Sc(Fe Si Fe magnetic moment was determined as to be equal to 1.5 μ at 8 K. Combining this result with a value of hyperfine magnetic field on Fe probes, the hyperfine coupling constant A in Sc(Fe Cu phases is estimated at about 11.6 T/μ at 8 K.

This study investigated changes in the crystal lattice, tribological properties and friction mechanism of AISI 316 steel irradiated with swift 160 MeV xenon ions. The irradiation process caused the increased roughness of the steel surface and the swelling of the material. The thickness of the irradiated layer increased by about 13 nm. Following irradiation with the fluences 2.5 × 1014 and 3.2 × 1014 (Xe24+/cm2), martensite formed in the surface layer. Fluctuating changes were also observed with respect to the coefficient of friction and the degree of wear of the AISI 316 steel samples. Irradiation also increased the microhardness of the steel.

This is the first study ever to show the impact of high-energy 160 MeV xenon ion irradiation on the properties of 100Cr6 bearing steel. The projected range (Rp) of xenon ions is 8.2 µm. Fluence-dependent variations in the coefficient of friction and wear of the 100Cr6 steel material have been observed. These changes correlate with shifts in the crystal lattice constant and variations in the oxygen, carbon, and iron content in the wear track. Fluence-dependent changes in these parameters have been observed for the first time. Irradiation reduces stresses in the crystal lattice, leading to crystallite size increase. The modifications in the properties of 100Cr6 steel result from radiation-induced defects caused by electronic ion stopping. The degree of these modifications depends on the applied irradiation fluence. Furthermore, the use of a higher irradiation fluence value appears to mitigate the effects produced by a lower fluence.

In this paper, results of positron annihilation lifetime spectroscopy (PALS) studies of MnFe 2 O 4 /MCM-41 nanocomposites in N 2 and O 2 atmosphere have been presented. In particular, the influence of manganese ferrite loading and gas filling on pick-off ortho -positronium ( o -Ps) annihilation processes in the investigated samples was a point of interest. Disappearance of the longest-lived o -Ps component with τ 5 present in the PAL spectrum of initial MCM-41 mesoporous material in the PAL spectra of MnFe 2 O 4 -impregnated MCM-41 measured in vacuum is a result of either a strong chemical o -Ps quenching or the Ps inhibition effects. The intensity I 4 of the medium-lived component initially increases, reaching a maximum value for the sample with minimum manganese ferrite content, and then decreases monotonically. Analogous dependence for the intensity I 3 of the shortest-lived component shows a maximum at higher MnFe 2 O 4 content. Filling of open pores present in the studied nanocomposites by N 2 or O 2 at ambient pressure causes partial reappearance of the τ 4 and τ 5 components, except a sample with maximum ferrite content. The lifetimes of these components measured in O 2 are shortened in comparison to that observed in N 2 because of paramagnetic quenching. Anti-inhibition and anti-quenching effects of atmospheric gases observed in the MnFe 2 O 4 /MCM-41 samples are a result of neutralization of some surface active centers acting as inhibitors and weakening of pick-off annihilation mechanism, respectively.

Nanoparticles of manganese ferrite were obtained by the impregnation of highly ordered mesoporous MCM-41 silica support. The investigated sample contained 20% wt. Fe. The obtained nanocrystallites were strongly dispersed in silica matrix and their size was about 2 nm. The sample annealing at 500°C led to increase of particle size to about 5 nm. The Mössbauer spectroscopy investigations performed at room temperature show on occurrence of MnFe 2 O 4 nanoparticle in superparamagnetic state for the sample annealed in all temperatures. The coexistence of superparamagnetic and ferromagnetic phase was observed at liquid nitrogen temperature. The sample annealed at 400°C and 500°C has bigger manganese ferrite particle and better crystallized structure. One can assign them the discrete hyperfine magnetic field components.