Effect of "ColdArc" WAAM Regime and Arc Torch Weaving on Microstructure and Properties of As-Built and Subtransus Quenched Ti-6Al-4V.

Defect-free thin-walled samples were built using wire arc additive manufacturing (WAAM) combined with the "coldArc" deposition technique by feeding a Ti-6Al-4V welding wire and using two deposition strategies, namely with and without the welding torch weaving. The microstructures formed in these samples were examined in relation to mechanical characteristics. The arc torch weaving at 1 Hz allowed us to interfere with the epitaxial growth of the β-Ti columnar grains and, thus, obtain them a lower aspect ratio.

Microstructures and Phases in Electron Beam Additively Manufactured Ti-Al-Mo-Zr-V/CuAl9Mn2 Alloy.

Electron beam additive manufacturing from dissimilar metal wires was used to intermix 5, 10 and 15 vol.% of Ti-Al-Mo-Z-V titanium alloy with CuAl9Mn2 bronze on a stainless steel substrate. The resulting alloys were subjected to investigations into their microstructural, phase and mechanical characteristics.

Al-AlNi In Situ Composite Formation by Wire-Feed Electron-Beam Additive Manufacturing.

The regularities of microstructure formation in samples of multiphase composites obtained by additive electron beam manufacturing on the basis of aluminum alloy ER4043 and nickel superalloy Udimet-500 have been studied. The results of the structure study show that a multicomponent structure is formed in the samples with the presence of CrC carbides, solid solutions based on aluminum -Al or silicon -Si, eutectics along the boundaries of dendrites, intermetallic phases AlNi, AlNi, Al5CoNi, and AlCo, as well as carbides of complex composition AlCCr, AlSiC, of a different morphology. The formation of a number of intermetallic phases present in local areas of the samples was also distinguished.

Macro- and Microstructure of In Situ Composites Prepared by Friction Stir Processing of AA5056 Admixed with Copper Powders.

This paper is devoted to using multi-pass friction stir processing (FSP) for admixing 1.5 to 30 vol.% copper powders into an AA5056 matrix for the in situ fabrication of a composite alloy reinforced by Al-Cu intermetallic compounds (IMC).

Evidence of Tribological Adaptation Controlled by Tribosynthesis of FeWO on an WC-Reinforced Electron Beam M2 Steel Coating Rubbed against a HSS Disk in a Range of Sliding Speeds.

In the present work, the tribological experiments on sliding the electron beam composite M2+WC coating have been carried out with characterization of the sample microstructures and phases both before and after the testing using metallography, SEM, EDS, and XRD. The sliding in the speed range 0.8-3.

In-Situ Al-Mg Alloy Base Composite Reinforced by Oxides and Intermetallic Compounds Resulted from Decomposition of ZrWO during Multipass Friction Stir Processing.

In the presented work, the effect of friction stir processing admixing the zirconium tungstate ZrWO powder on the microstructure, mechanical and tribological properties of the AA5056 Al-Mg alloy stir zone has been studied. The FSP resulted in obtaining dense composite stir zones where α-ZrWO underwent the following changes: (i) high-temperature transformation into metastable β'-ZrWO and (ii) decomposition into WO and ZrO oxides followed by the formation of intermetallic compounds WAl and ZrA. These precipitates served as reinforcing phases to improve mechanical and tribological characteristics of the obtained fine-grained composites.

The Effect of Heat Input, Annealing, and Deformation Treatment on Structure and Mechanical Properties of Electron Beam Additive Manufactured (EBAM) Silicon Bronze.

Electron beam additive wire-feed manufacturing of Cu-3wt.%S-0.8wt.

In Situ Intermetallics-Reinforced Composite Prepared Using Multi-Pass Friction Stir Processing of Copper Powder on a Ti6Al4V Alloy.

Multi-pass friction stir processing (FSP) was used to obtain a titanium alloy/copper hybrid composite layer by intermixing copper powder with a Ti6Al4V alloy. A macrostructurally inhomogeneous stir zone was obtained with both its top and middle parts composed of fine dynamically recrystallized α- and β-Ti grains, as well as coarse intermetallic compounds (IMCs) of TiCu and TiCu, respectively. Some β grains experienced β → α decomposition with the formation of acicular α-Ti microstructures either inside the former β-Ti grains or at their grain boundaries.

Heat Input Effect on Microstructure and Mechanical Properties of Electron Beam Additive Manufactured (EBAM) Cu-7.5wt.%Al Bronze.

Electron beam additive wire-feed deposition of Cu-7.5wt.%Al bronze on a stainless-steel substrate has been carried out at heat input levels 0.

Microstructure and Corrosion Resistance of AA4047/AA7075 Transition Zone Formed Using Electron Beam Wire-Feed Additive Manufacturing.

A gradient transition zone was obtained using electron beam deposition from AA4047 wire on AA7075 substrate and characterized for microstructures, tensile strength and corrosion resistance. The microstructure of the transition zone was composed of aluminum alloy grains, Al/Si eutectics and Fe-rich and Si-rich particles. Such a microstructure provided strength comparable to that of AA7075-T42 substrate but more intense corrosion due to the higher amount of anodic MgSi particles.

Evolution of Microstructure in Friction Stir Processed Dissimilar CuZn37/AA5056 Stir Zone.

Dissimilar friction stir processing on CuZn37/AA5056 was performed to study structural and phase evolution of a friction stir zone. Formation of 5-10 μm intermetallic compounds (IMCs) such as AlCu was the main type of diffusion reaction between copper and aluminum. Other alloying elements such as Mg and Zn were forced out of the forming AlCu grains and dissolved in the melt formed due to exothermic effect of the AlCu formation.

In Situ Investigation of Strain Localization in Sintered, Porous Segmented Alumina.

Evaporation of paraffin and ultra-high-molecular-weight polyethylene admixed with alumina powder for the slip casting and sintering process allowed the obtainment of segmented porous alumina ceramics with 50% total porosity, whose deformation behavior we studied. Structurally, these ceramic materials were composed of large and small pores, and a system of discontinuities subdividing the samples into segments. Using digital image correlation (DIC), strain distribution maps were obtained that allowed the observation of strain localization zones, where primary cracks propagated along the interblock discontinuities.

[Optic nerve pathology in the structure of diagnostic errors inpatients referred for cataract surgery].

Aim: to study the frequency of misdiagnosis of cataract in patients with optic nerve pathology or amblyopia and to identify its main causes.

Material And Methods: The study enrolled 381 patients (381 eyes) wrongly diagnosed with cataract. A standard set of eye tests was performed.

[Diagnostic errors when referring patients for cataract surgery].

Aim: To study the frequency of patients with macular pathology being wrongly diagnosed with cataract and possible reasons for this to occur.

Material And Methods: A total of 1390 patients (1390 eyes), in whom cataract turned out to be not the main cause of visual impairment, were recruited as research subjects. To reveal the reasons for misdiagnosis, we resorted to methods of ophthalmic examination that are available at ambulatory care facilities, i.

[The role of changes in matrix metalloproteases and chitotriosidase in the mechanism of protective effect of atorvastatin in experimental murine lipemia].

The effect of atorvastatin on the activity of chitotriosidase (CTO) and total matrix metalloproteases (MMPs)-new markers of cardiovascular disorder-was studied on the model of murine lipemia induced by single administration of Triton WR 1339 in two doses, 500 mg/kg (mild lipemia) and 850 mg/kg (severe lipemia). A hypolipidemic effect of atorvastatin was observed in mice with mild lipemia, but not in those with severe lipemia. In both mild and severe lipemia cases, the serum CTO activity was increased upon the combined administration of atorvastatin and Triton WR 1339, correlating with cholesterol and triglyceride concentration.

In vivo effect of selective macrophage suppression on the development of intrahepatic cholestasis in mice.

We studied the role of selective suppression of liver Kupffer cells (gadolinium chloride, 14 mg/kg intravenously) in the development of intrahepatic cholestasis in CBA/C57B1/6 mice after intraperitoneal injection of alpha-naphthylisothiocyanate in a single dose of 200 mg/kg. Pretreatment with gadolinium chloride increased the severity of cholestasis and signs of liver damage. Gadolinium accumulation in the liver peaked after 24 h and was accompanied by a decrease in activities of cathepsin D and cathepsin B and concentration of matrix metalloprotease-2.

Activity of lysosomal enzymes in the bile and serum of mice with intrahepatic cholestasis.

Lysosomal enzyme activity in the bile and blood serum was compared in mice with experimental intrahepatic cholestasis induced by alpha-naphthyl isothiocyanate and Triton WR 1339. Triton WR 1339 increases the synthesis of cholesterol (fatty acid precursor) in liver cells. The development of intrahepatic cholestasis was confirmed by the increase in activities of alkaline phosphatase and gamma-glutamyltransferase in blood serum.

[Cystatin C: a biological role and impaired secretion in viral hepatitis c and hepatic cirrhosis].

Cystatin C is a non-glycated cationic protein with a molecular weight of 13.3 kD, which belongs to the superfamily of cystatins; its basic function is to inhibit and regulate the activity of cysteine proteinase. In apparently healthy individuals, the extracellular concentration of cystatin C is shown to be substantially higher in serum than in urine and bile.

Changes in the concentration of tissue inhibitor of type 1 metalloproteinases in blood serum and liver of mice with CCl4-induced hepatitis.

The concentration of tissue inhibitor of type 1 metalloproteinases in blood serum from intact CBA mice measured by enzyme immunoassay is similar to that in healthy humans. The concentration of tissue inhibitor of type 1 metalloproteinases in mouse bile was higher than in blood serum, while its concentration in liver homogenate more than 1000-fold exceeded that in the serum, which attests to its primarily intracellular localization in the liver. Loading of liver cell lysosomes with Triton WR-1339 and development of intrahepatic cholestasis did not affect the concentration of tissue inhibitor of type 1 metalloproteinases in liver homogenate and bile.

[Characteristics of cerebral hemodynamics and psychological adaptation of patients with myocardial infarction during period of rehabilitation and convalescence].

Cerebral circulation and psychological state of 93 myocardial infarction patients aged from 29 to 60 years have been studied. The comparison of data concerning cerebral circulation with psychological profile of these patients enables us to make a conclusion that there is interrelation between the state of cerebral hemodynamics which ensures brain homeostasis and psychological adaptation of patients with myocardial infarction at different stages of the disease

[Treatment of patients with acute pneumonia].

Efficiency was studied of treatment of acute pneumonia (AP) in 148 patients with a focal croupous form. In the grave course of AP, antibacterial therapy with benzilpenicillin combined with sulphanilamide agents biseptol and nitrofuran was tried, the correcting therapy having been instituted on obtaining findings from assays of the sputum for sensitivity of the microflora to antibiotics. In those cases with Friendländer's bacilli recoverable, methicillin, oxacillin, macrolids, cephalosporins and some other agents were antibiotics of choice.

Expression of cell adhesion molecules and lymphocyte-endothelium interaction under simulated hypogravity in vitro.

Using histochemical staining and FACS-analysis we have studied the basal and TNF-alpha induced expression of E-selectin, ICAM-1 and VCAM-1 in human umbilical vein endothelial cells (ECs) exposed to simulated hypogravity. Control ECs did not contain detectable amounts of E-selectin or VCAM-1 but were ICAM-1 positive. As soon as after 6-8 hrs of clinorotation at 5 RPM the cellular content of ICAM- 1 increased.