271 research outputs found
Phase Composition and Defect Substructure of Strengthening Layer Surfaced on Low Alloyed Steel
The microstructure and microhardness distribution in surface of low carbon Hardox 450 steel coated with alloyed powder wires of different chemical compositions are studied. It is shown that the microhardness of 6-8 mm thickness surfaced layer exceeds that of base metal by more than 2 times. The increased mechanical properties of surfaced layer are caused by the submicro and nanoscale dispersed martensite, containing the niobium carbides Nb2C, NbC and iron borides Fe2B. In the bulk plates a dislocation substructure of the net-like type with scalar islocation density of 10^11 cm^-2 is observed. The layer surfaced with the wire containing B possesses the highest hardness. The possible mechanisms of niobium and boron carbides formation in surfacing are discusse
The possibilities of the Internet in the formation of a healthy lifestyle of young generation
The article analyzes the role of the Internet in the lives of younger generation. In the course of the study revealed the influence of social networks on the formation of the needs of young people in physical culture and sportsΠ ΡΡΠ°ΡΡΠ΅ ΠΏΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π° ΡΠΎΠ»Ρ ΠΈΠ½ΡΠ΅ΡΠ½Π΅ΡΠ° Π² ΠΆΠΈΠ·Π½ΠΈ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ»ΠΎΠ΄ΠΎΠ³ΠΎ ΠΏΠΎΠΊΠΎΠ»Π΅Π½ΠΈΡ. Π Ρ
ΠΎΠ΄Π΅ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½Π½ΠΎΠ³ΠΎ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ Π²ΡΡΠ²Π»Π΅Π½ΠΎ Π²Π»ΠΈΡΠ½ΠΈΠ΅ ΡΠΎΡΠΈΠ°Π»ΡΠ½ΡΡ
ΡΠ΅ΡΠ΅ΠΉ Π½Π° ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΏΠΎΡΡΠ΅Π±Π½ΠΎΡΡΠΈ ΠΌΠΎΠ»ΠΎΠ΄Π΅ΠΆΠΈ Π² Π·Π°Π½ΡΡΠΈΡΡ
ΡΠΈΠ·ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΊΡΠ»ΡΡΡΡΡ ΠΈ ΡΠΏΠΎΡΡΠΎ
Fractography of Fatigue Fracture Surface in Silumin Subjected to Electron-Beam Processing
The surface modification of the eutectic silumin with high-intensity pulsed electron beam has been carried out. Multi-cycle fatigue tests were performed and irradiation mode made possible the increase in the silumin fatigue life more than 3.5 times was determined. Studies of the structure of the surface irradiation and surface fatigue fracture of silumin in the initial (unirradiated) state and after modification with intense pulsed electron beam were carried out by methods of scanning electron microscopy. It has been shown, that in mode of partial melting of the irradiation surface the modification process of silicon plates is accompanied by the formation of numerous large micropores along the boundary plate/matrix and microcracks located in the silicon plates. A multi-modal structure (grain size within 30-50 ΞΌm with silicon particles up to 10 [mu]m located on the boundaries) is formed in stable melting mode, as well as subgrain structure in the form of crystallization cells from 100 to 250 [mu]m in size). Formation of a multi-modal, multi-phase, submicro- and nanosize structure assisting to a significant increase in the critical length of the crack, the safety coefficient and decrease in step of cracks for loading cycle was the main cause for the increase in silumin fatigue life
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