Ultrafine-grained structure formation in Ti-6Al-4V alloy via warm swaging

The influence of warm swaging on the structure and properties of Ti-6Al-4V alloy was studied. Warm swaging of the alloy in the interval 680-500°C with the total strain of ε=2.66 was found to be resulted in the formation of a homogeneous globular microstructure with a grain size of 0.4μm in both longitudinal and transversal sections. Room temperature tensile strength and tensile elongation of the swaged alloy was 1315MPa and 10.5%, respectively. Ultrafine-grained Ti-6Al-4V alloy produced by swaging exhibited good workability at 600-700°

Twinning-induced formation of nanostructure in commercial-purity titanium

In the present work the influence of various parameters on formation of nano- or ultrafine-grained structure in commercial-purity titanium during large deformation was quantified using TEM and EBSD. The beneficial effect of twinning on the kinetics of microstructure refinement in titanium was revealed. It was shown that deformation twinning (and therefore nanostructure formation) can be intensified via decrease in temperature, increase in the initial grain size and decrease in the impurities content. The minimum grain size at which twinning can still operate in commercial-purity titanium was determined to be ~1μm. It was shown that rolling to a thickness strain of 93% at -196°C resulted in the formation of a microstructure with a grain/subgrain size ~80 n

Microstructure evolution of commercial-purity titanium during cryorolling

Electron backscatter diffraction and transmission electron microscopy have been used to analyze the microstructural evolution of titanium during rolling at a cryogenic temperature (T = –196°C). It has been found that intensive twinning at the cryogenic deformation temperature accelerates the kinetics of micro structure refinement. The quantitative analysis of microstructure evolution in titanium upon cryorolling has shown that structure evolution is mainly related to mechanical twinning in the initial stages cryorolling is discusse

Microstructure and texture evolution of a high manganese TWIP steel during cryo-rolling

The influence of rolling at 77 K and 293 K to a true strain of 2.66 on the microstructure and texture evolution and mechanical behavior of a TWIP Fe-0.3C-23Mn-1.5Al steel was quantified. The microstructure evolution at both temperatures of deformation was associated with an increase in the dislocation density and extensive twinning, following by the development of a cell structure and shear band

Effect of second phase particles on mechanical properties and grain growth in a CoCrFeMnNi high entropy alloy

Effect of annealing of a cold-worked CoCrFeMnNi alloy at temperatures of 500-900°C for 1-50 h on the structure and mechanical properties was studied in the present wor

Characteristics of hotel premises in Belgorod city

Hotel industry is regarded as one of the factors in the development of tourism and the initial basis for planning the production of the tourist product. It determines the specificity of the development of tourism, being the basis for the production of the tourism product in planning the priorities of the investment policy. The article presents the results of the authors’s research, as well as materials open print and electronic resources. The authors analyzed the state of hotel real estate market of Belgorod, the structure of the number of rooms, hotel occupancy assessed by type of rooms, highlighted promising areas of the hotel business. It should be noted, that the development of domestic tourism, the growth of business and cultural activity in the region will contribute to the further development of tourism infrastructure and, in particular, the hotel industryyesБелгородский государственный университе

Kinetics of recrystallization and grain growth in an ultra-fine grained CoCrFeNiMn-type high-entropy alloy

A novel high entropy alloy based on the CoCrFeMnNi system with substantial amounts of Al and C was studied. After cold rolling and annealing at 973-1273 K a duplex ultrafine grained structure composed of the recrystallized fcc grains and M23C6 and B2 particles was produced. Analysis of the coarsening behavior of grains and particles growth suggested that kinetics of both was controlled by volume diffusion. The apparent activation energy of structure coarsening during recrystallization was evaluate

Evolution of microstructure and mechanical properties of a CoCrFeMnNi High-entropy alloy during high-pressure torsion at room and cryogenic temperatures

High-pressure torsion is applied to a face-centered cubic CoCrFeMnNi high-entropy alloy at 293 and 77 K. Processing by HPT at 293 K produced a nanostructure consisted of (sub)grains of ~50 nm after a rotation for 180°. The microstructure evolution is associated with intensive deformation-induced twinning, and substructure development resulted in a gradual microstructure refinemen

Microstructure evolution during warm working of Ti-5Al-5Mo-5V-1Cr-1Fe at 600 and 800°C

Microstructure evolution during compression to the true height strain 0.29, 0.69, or 1.2 at 600 and 800. °C of the Β-rich titanium alloy Ti-5Al-5Mo-5V-1Cr-1Fe (VT22) with an initial lamellar microstructure was established using scanning and transmission electron microscopy. It was found that microstructure evolution at both temperatures was controlled primarily by substructure evolution within the Β phase. At 800. °C, extensive recovery within the Β phase resulted in the formation of a stable structure comprising subgrains ~1.5. μm in diameter. During deformation at this temperature, lamellae of the α phase fragmented via a boundary-grooving mechanism. Due to the sluggish diffusion kinetics, however, spheroidization at 800. °C was incomplete. At the lower processing temperature, recovery processes within the Β phase were much slower, leading to greater refinement of the Β matrix. The decomposition of the metastable Β phase during warm working, gave rise to very fine α-lath precipitates, which resulted in the formation of an ultrafine microstructure with a grain size of 0.5. μm. © 2012 Elsevier B.V

Recrystallized microstructures and mechanical properties of a C-containing CoCrFeNiMn-type high-entropy alloy

The effect of cold rolling to 80% thickness reduction and annealing at 973-1373 K for 1h our on the microstructure and mechanical properties of a C-containing CoCrFeNiMn high-entropy alloy was studied. Cold rolling significantly strengthened the alloy to the yield strength of 1310 MPa. Annealing at 973 K or 1073 K resulted in incomplete recrystallization of an fcc matrix and M23C6-type carbide precipitations aligned with highly elongated grains/subgrains. Complete recrystallization occurred during annealing at 1173-1373