[en] The possibility is shown for application of the kinetic equation of creep, suggested lately for structurally stable steels, to high-nickel ageing alloys. The equation describes strains in high-temperature ageing 03Kh20N45M4BCh and 03Kh20N45MBRTs alloys at 823-1023 K temperatures. The temperature dependences for the coefficients in thquations considered are determined

[en] Aging of the 03Kh20N45M4BCh alloy in the 500-750 deg C temperature range is investigated, vacancy swelling of the alloy is observed here. Phases precipitating in the material are shown to result in appearance of elastic distortions in the lattice and effective breaking of dislocations. The mentioned factors in combination with the experimentally observed metastability of the 03Kh20N45M4BCh alloy are responsible for its high resistance to vacancy swelling

[en] Methods of X-ray line profile analysis and transmission electron microscopy are used to study dislocation structure of preliminarily deformed specimens of high nickel alloy Kh20N45M4BCh before and after irradiation in BN-600 reactor at three damage rate levels. Dislocation loop size and concentration linear dislocation density are determined depending on irradiation parameters and initial dislocation network density. The results obtained can be used to forecast microstructural changes at more high radiation doses

[en] Heat-resistance of 03KH20N45M4BCh alloy at 923 K under reactor radiation after helium and hydrogen ion irradiation in the 3x10²²-2x10²⁴ ion/m² dose range are investigated. Investigations into kinetics of helium thermal sorption releasing at specimen heating up to 1273 K at constant velocities of 0.1-0.4 deg Cxs^-1 are carried out. Based on data on gas release it is concluded that the most part of diffusion-mobile helium after implantation is in the surface layer not more than 5 μm, and concentration in it is not less than 10^-2 at.%. The results obtained in the given paper on durability and creep show that long-term strength of the specimens preliminarily irradiated with helium ions is by 30-40 mPa lower than that in the initial state

[en] Effect of thermal changes on strength and deformation characteristics of austenitic high-nickel alloy 03Kh20N45M4BCh, of ferritic steel 01Kh13MT and titanium α-alloy Ti-2Al-1.5Zr subjected to neutron irradiation is investigated. The phenomenon of thermocyclic recovery of mechanical properties for all irradiated metals during their thermocycling from 50 to 300 deg C and from 50 to 200 deg C for titanium alloy is established. Long-term isothermal annealing of these materials at the temperature being equal to the maximum temperature in the thermal cycle does not affect the mechanical properties. A vacancy model for healing radiation defects in thermal changes is suggested

[en] Results of an investigation of the structure and phase constitution of ferritic steels, austenitic steels and 45% Ni alloys after thermal ageing prior neutron irradiation, prior helium ingection and during irradiation are presented. Ageing after preirradiation and particular during irradiation is shown to result in the precipitation of phases differing from the ones at thermal ageing in both morphology and size, density and type. Ageing induced hardening of candidate materials for fusion is discussed

[en] Using the method of thermosorptional spectroscopy the effect of grain size and cold deformation on helium evolution from the alloys 03Kh20N45M4BCh (ChS-42) and 03Kh20N45M4BRTs (ChS-43) in the process of annealing is investigated. It is ascertained that both the decrease in grain size and preliminary cold deformation (5 %) of the samples suppress considerably helium evolution from ChS-42 and do not practically affect helium evolution from ChS-43. Consequently, low-temperature stage of helium evolution from samples (approximately 280 deg C) is related to helium, initially present on the grain boundaries near the surface

[en] Components for the core of a water-moderated, water-cooled power reactor (VVER) are fabricated from highly ductile materials which precludes the failure mechanism approach to assessment of fitness for work in a non-irradiated condition. A significant radiation hardening and embrittlement of these materials toward the end of the operating period means that an assessment of their cracking proves not only to be possible, but imperative. For an investigation of the cracking of VVER core materials, a special flat specimen is used for axial tension tests. Tests of specimens under static or cyclic loading were conducted on an existing remotely controlled apparatus consisting of a tensile-testing machine which was located in a chamber with a biological shield, control panels, and oil pumps, located in an operating room. The apparatus allows the determination of the properties of ductility breakdown of previously irradiated thin-gauge specimens: the critical value of the I-integral, the coefficient of stress intensity, the beginning of a fracture, and at the same time the properties of resistance to growth of a fatigue crack through tests both in air and in corrosive media. As a result of a metallographic analysis of the nature of the breaks in the nonirradiated and irradiated specimens, it was found that in all cases the failure of the specified materials originated with the formation of a 'cup' fissure and appeared to be transcrystalline. Use of an existing apparatus not only allows one to test materials for use in elements and assemblies in VVER cores, but also to more soundly assess their service life

[en] The strain release of helium from nickel, Kh20N45M4 and 0Kh16N15M3 alloys is described. A strong influence of the implantation method, and helium concentration on the strain release is obtained. The results are discussed in terms of an interaction of helium atom and bubble with dislocation. 7 refs.; 5 figs. (author)

[en] Structural damages of austenitic stainless steel 18-10 and high-nickel alloy 20-45, irradiated with 40 keV energy helium ions under loads under isothermal and thermocyclic conditions and as a result of postradiation high-temperature deformation, are studied using transmission and scanning electron microscopy and helium thermodesorption methods. Parameters of the formed helium bubbles and the degree of near-the-surface layer swelling sufficiently depend on the level of applied external stresses and thermal cycling. Correlation between the rate of helium evolution and the degree of sample deformation during high-temperature creep testing is ascertained