Search

At present, for selective laser melting (SLM, Selective Laser Melting), studying the influence of characteristics of blowing and a loading of the working space on mechanical properties of titanium Ti6Al4V alloy is an urgent task. In the work, tensile samples were studied, for which as a result of a different loading of the building space, there was a pause of different duration between the deposition of powder and return of the laser beam. Based on the analysis of the values of mechanical properties, it was found that characteristics of strength of test samples in the area of the inlet nozzle of inert gas blowing have a value by 3-5 % lower compared to the central area of the platform with a range of values of ± 2 %, in the area of the outlet nozzle, the value is lower by 3-5 % compared to the central area, a range of values is ± 10 %. It was found that an increase in the pause from 50 to 65 s leads to a decrease in strength and ductility characteristics by 23 and 10 %, up to 80 s by 33 and 0.7 %, respectively. [ABSTRACT FROM AUTHOR]

Systematic study of forward-angle inclusive yields of nuclei with atomic numbers 8 < Z < 20 produced in nucleus-nucleus collisions of the 40Ar projectile on the 9Be target in the Fermi energy domain (36.5 A MeV) was carried out. The reaction products were measured by using the double achromatic fragment-separator COMBAS in the spectrometry mode at Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research (Dubna). Relative yields of isotopes were obtained and compared with the empirical parametrization of fragmentation cross section (EPAX), abrasion–ablation (AA) and available experimental data. [ABSTRACT FROM AUTHOR]

In the modern manufacturing of parts of metal powder, the method of Selective Laser Melting (SLM) has become widespread. In Ukraine, the LLC "Additive Laser Technologies of Ukraine" is engaged in the development of equipment for manufacturing parts of metal powders by SLM technology. Nowadays, for this equipment, the relevant task is the development of a procedure for choosing the parameters of the process of melting metal powder, providing the necessary mechanical and service properties of parts. For the investigations, three experimental cylindrical specimens of Co-Cr-Mo alloy were made in the vertical direction for tensile test according to ISO 6892:2019 -- with a diameter of the working zone of 5 mm, with a controlled stop at a height of 18 mm from the beginning of the working zone, the total length of which is 28 mm. As a result of the analysis of the values of mechanical properties, it was found that the ultimate strength of the experimental specimens of Co-Cr-Mo alloy made by SLM technology with a controlled stop during 24 h decreases compared to the specimens made without a controlled stop -- by ~13 %, relative elongation -- by ~1 % and reduction in area -- by ~17 %. It was found that for the experimental specimens with a stop in the manufacturing process, the deviation from the average values was: for ultimate strength ~11 %, relative elongation ~62 % and reduction in area of ~21 %. This is predetermined by failure of one of the specimens at the place of a stop. The use of parts with a production defect (stop) should be significantly restricted respective to a probable significant softening and embrittlement of a product. [ABSTRACT FROM AUTHOR]

In heavy-ion-induced projectile fragmentation reactions at Fermi energies vast amount of different nuclides far from stability line are born. These neutron or proton-reach isotopes can be used as secondary beams to obtain even more exotic new isotopes or to study nuclear interactions of halo nuclei and their radii and other yet unsolved scientific problems. Radioactive isotopes produced in fragmentation reactions can be used in medical and industrial applications. In this paper we present velocity and isotope distributions of fragments from Na to Ca obtained in the collision of Ar beam of 36.5 MeV on Be target on COMBAS mass-spectrometer at FLNR, JINR. We compare the experimental results with the calculations fulfilled in combined transport-statistical model and show good agreement between them. [ABSTRACT FROM AUTHOR]

Precision high-voltage sources have been developed for nuclear radiation detectors (semiconductor detectors, detectors based on photoelectronic multipliers, etc.). Instead of a specialized high-voltage transformer, a common network (~220 V) POL-12012 transformer was used together with a voltage multiplier. The electrical parameters of the units are as follows: range, from 0 to ±2500 V; power, ≤10 W; efficiency, up to 77%; ripples at a load of 2 MΩ (2 kV), 1 mV; conversion frequency, up to 150 kHz; manual/external control; smooth voltage rise/drop; shutdown upon an overload; temperature drift, ≤0.004%/°C; and operating temperature, –40 to +60°C. Implementation: 3U Euromechanics or an autonomous unit of 80 × 80 × 40 mm. The sources are used in a number of experiments and industrial plants, where they provide quality, reliability, a temperature range, and the required functionality. [ABSTRACT FROM AUTHOR]

The projectile fragmentation reactions of 22Ne at 42 MeV/nucleon on 9Be and 181Ta targets have been studied by the double achromatic kinematic separator COMBAS at the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research (Dubna). Velocity distributions of the fragments were measured and the competition between different mechanisms was observed. The production cross sections have been obtained and compared with the empirical parametrization of fragmentation cross section (EPAX) and heavy-ion phase space exploration (HIPSE) models. [ABSTRACT FROM AUTHOR]