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

Effect of temperature and strain on the formation of elongated fine grained structure in middle carbon steel during large plastic deformation

The influence of deformation temperature and strain rate on the mechanisms of elongated fine grain (EFG) formation in the medium-carbon steel was studied. Compression tests were carried out at the temperatures in range of 673-973K at three different strain rates: 10-2, 1.3*10-3 and 10-4 s-1. Presence of two temperature intervals with different dominant mechanisms of deformation was identified: low temperature (673-823K) interval and high temperature (873-973K) interval. Microstructure evolution during deformation at strain rate of 1.3*10-3 s-1 and different temperatures was studied. Also was investigated the microstructure and mechanical properties of steel after warm plastic deformatio

Kinetics of grain refinemet in metallic materials during large strain deformation

The development of ultrafine grained microstructures in austenitic stainless steel and pure titanium subjected to large strain deformation was comparatively studied. The change in the volume fractions of newly developed ultrafine grains was used to quantify the progress in grain refinement during plastic deformatio

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

Mechanical properties, biodegradation, and biocompatibility of ultrafine grained magnesium alloy WE43

In this work, the effect of an ultrafine-grained (UFG) structure obtained by multiaxial deformation (MAD) on the mechanical properties, fatigue strength, biodegradation, and biocompatibility in vivo of the magnesium alloy WE43 was studie

Laser beam welding of a low density refractory high entropy alloy

In particular,the effect of different pre-heating temperatures was examined. Due to the low ductility of the material, laser beam welding at room temperature resulted in the formations of hot cracks. Sound butt joints without cracks were produced using pre-heating to T≥600 ◦C. In the initial as-cast condition, the alloy consisted of coarse bcc grains with a small amount of lens-shaped C15 Laves phase particle

Grain-structure development in heavily cold-rolled alpha-titanium

High-resolution electron back-scatter diffraction (EBSD) analysis was employed to establish mircostructure evolution in heavily cold-rolled alpha-titanium. After thickness reductions of 75% to 96%, significant microstructure and texture changes were documented. The surface area of high-angle grain boundaries was almost tripled, thus giving rise to an ultra-fine microstructure with a mean grain size of 0.6 μm. Moreover, orientation spread around typical ‘split-basal’ rolling texture substantially increased. These effects were suggested to be related to the enhancement of pyramidal 〈c+a〉 slip. Grain-structure development in heavily cold-rolled alpha-titanium (PDF Download Available

Structure and Properties of High Entropy Alloys

Высокоэнтропийные сплавы — сплавы, содержащие несколько основных элементов, с близкой к эквимолярной концентрацией. Рассматриваются особенности строения их структуры и физико-механических свойств. Показаны возможности получения более высокого уровня свойств высокоэнтропийных сплавов по сравнению с традиционными сплавами.High-entropy alloys — alloys containing several basic elements close to equimolar concentration. The report discusses the principles and algorithms for predicting new alloys, the features of their structure and physico-mechanical properties. The possibilities of obtaining a higher level of properties in comparison with traditional alloys are shown.Работа выполнена при финансовой поддержке РНФ (соглашение № 19-79-30066) с использованием оборудования Центра коллективного пользования «Технологии и материалы НИУ «БелГУ»».The work was carried out with the financial support of the RNF (Agreement No. 19-79-30066) using the equipment of the Center for Collective Use “Technologies and Materials of the National Research University BelSU”

Effect of Mn and V on structure and mechanical properties of high-entropy alloys based on CoCrFeNi system

Microstructure and mechanical properties of equimolar composition alloys FeCrCoNi, FeCrCoNiV, FeCrCoNiMn and FeCrCoNiMnV were studied in as-solidified and annealed conditions. The FeCrCoNi and FeCrCoNiMn alloys were single-phase FCC solid-solutions in both conditions. However, the FeCrCo- NiV and FeCrCoNiMnV alloys consisted of the intermetallic r-phase matrix with a tetragonal crystal lattice and precipitates of a disordered FCC phase. The crystal structures of these alloys were found to be not affected by annealin