Russian Metallurgy (Metally)最新文献

Abstract—A data processing algorithm is developed to perform a statistical analysis of the results of end-to-end production control for large (≈5 t) cylindrical forgings of variable cross sections made of heat treatable 38KhN3MFA-Sh steel with a retained as-cast structure. A two-parameter criterion ({{Delta }_{{ij}}} - {{bar {X}}_{{ij}}}) is proposed as an additional characteristic of cold resistance. Here, Δ_ij = ({text{KCU}}_{{{text{max }}i}}^{{ + 20}}) – ({text{KCU}}_{{{text{min }}j}}^{{ - 50}}) characterizes the steepness of impact toughness reduction for the standard testing temperatures of forgings (20, –50°C), and ({{bar {X}}_{{ij}}}) = (({text{KCU}}_{{{text{max }}i}}^{{ + 20}}) + ({text{KCU}}_{{{text{min }}j}}^{{ - 50}}))/2 represents its absolute level. A correlation is established between the proposed criterion and the process parameters, namely, the chemical composition of steel after electroslag remelting, the heating temperature of ingot for forging, the forging start temperature, and the second tempering temperature. This approach can be useful for cold resistance ranking of forgings.

Abstract—The influence of hydrogen alloying and subsequent vacuum annealing of Ti–8.7Al–2.0Mo–1.5Zr alloy on cutting force and temperature in the cutting zone during milling has been studied. A relation between these parameters and the arising phase composition and structure has been shown. It has been found that the temperature and cutting force variations with structure differ from those observed in industrial titanium alloys.

Abstract—The structure and properties of SnSbCu–Al(Bi) composite coatings formed on a steel substrate by arc surfacing with a tungsten electrode in an inert gas are studied. Extrusion-made rods based on a B83 alloy containing 3 wt % Al(Bi) reinforcing particles with a size of no more 100 μm are tested as filler materials. SnSb crystals in the composite coatings have been shown to change their morphology and to be smaller in size compared to B83 alloy coatings. The tribological properties (friction coefficient, wear rate, friction stability coefficient) of the composite coatings are superior to those of a B83 antifriction matrix alloy.

Abstract—The structure, phase composition, mechanical properties, and biocompatibility of medical Ti–20 at % Nb–7.5 at % Ta and Ti–20 at % Nb–10 at % Ta alloys are studied after warm rolling to a thickness of 1.5 mm and subsequent quenching from 600 and 800°C. The alloys consist mainly of the β phase; the alloy with 7.5 at % Ta also contains traces of the α'/α" phases. Quenching from 600°C reduces the tensile strength of alloys to 526–528 MPa, and quenching from 800°C reduces it to 499–506 MPa. The relative elongation of the rolled alloys is 9.7–9.8%. After quenching from 600 and 800°C, it increases to 13.3–13.5 and 15.5–19.4%, respectively. The tantalum content affects the manifestation of the hyperelasticity effect; for the quenched Ti–20Nb–7.5Ta alloy, the hyperelastic deformation is ~1.5%, and this effect for the Ti–20Nb–10Ta alloy is weakly expressed. Both alloys do not have a toxic effect on human neuroblastoma SH-SY5Y cells. The quenched Ti–20Nb–7.5Ta alloy is the most promising composition for the use in implants.

Abstract—Approach is considered to the formation of a powder equiatomic high-entropy Fe–Cr–Co–Ni–Mn alloy coating, which is based on mechanical alloying of elemental powders, a slurry method of depositing a powder mixture, induction sintering of the powder coating, and its subsequent electromechanical treatment (EMT), namely, surface plastic deformation with simultaneous resistive heating of a deformation zone. High cooling rates of the deformation zone (≈10⁴ K/s) during EMT are shown to provide the formation of a rapidly quenched structure in the coating, which favors an increase in the coating microhardness to 230 ± 15 HV from 180 ± 20 HV after sintering along with an increase in the coating density.

Abstract—The behavior of fuel rods (FRs) with E110 alloy (Zr–1% Nb) cladding, which operated as part of fuel assemblies in a VVER-1000 reactor up to a fuel burnup of 62 (MW day)/kgU, is studied under the conditions modeling an off-normal situation during dry storage: air inflow into an FR through primary through-wall defects in the cladding and the interaction of air with the fuel. Through-wall defects are created at different heights relative to the fuel core: in the lower part of the cladding in a certain FR, and in the middle of the fuel column in another FR. The states of the defects, their dimensions, fission product release and distribution in the fuel, fuel fragmentation, the structure and mechanical properties of the cladding, and the orientation of zirconium hydrides are studied. Additional oxidation of uranium dioxide is shown to occur at the sites of air penetration into the FRs through artificial cuts; this is accompanied by an increase in its volume, which causes a local increase in the cladding diameter and the defect width and the release of gaseous fission products.

Abstract—Chemical composition and structure are shown to influence the characteristics of superelastic behavior of a NiTi alloy wire used as reinforcing filler in a composite material with a polyethylene matrix. A method is proposed to estimate the performance of titanium nickelide wire reinforcing elements during their bending deformation. A technique is proposed to calculate the optimum volume fraction of the filler, which ensures high superelastic properties of the composite material.

Abstract—Computer simulation methods are used to study the ballistic properties of a VT23 titanium alloy barrier plate during high-speed interaction with a conical striker. The gradient structure of the plate across thickness is taken into account in the model using a hardness parameter. The Lagrange grid method and particle method are applied. The results of computer simulation of the collision of a striker and a titanium alloy plate agree qualitatively with the experimental data of bench tests.

Abstract—The structure and properties of composite coatings, which are formed by argon-arc surfacing and are based on a B83 alloy reinforced with 3 wt % Al–Bi or Ti₂NbAl intermetallic particles less than 100 μm in size are investigated. The composite coatings are found to have a fine-grained structure and a significantly higher fraction of SnSb intermetallic precipitates with cross-sectional area less than 5000 μm², namely, 70 and 100% for Al–Bi and Ti₂NbAl reinforcement, respectively. In contrast, 45% of the SnSb particles in the cast matrix alloy coating have surface area exceeding 5000 μm². In terms of hardness and tribotechnical characteristics, the composite coatings surpass the cast B83 alloy coatings. The composite coatings reinforced with Ti₂NbAl particles exhibit the best hardness (36 HB) and wear rate (3.5 mm³/m), and the coatings containing Al–Bi particles have the lowest friction coefficient (0.133).

Abstract—The linear thermal expansion coefficients (LTECs) of the α solid solution and the T₁ (Al₂CuLi) intermetallic phase in a V-1480 (Al–Cu–Li) alloy are determined by X-ray diffraction in the temperature range 100–500°C. The fcc α solid solution is found to have an LTEC of 26.2 × 10^–6 K^–1, and the hcp T₁ phase has an LTEC of 20.1 × 10^–6 K^–1 along the a axis and 5.2 × 10^–6 K^–1 along the c axis. T₁ phase particles have an unusual platelike shape. They are nearly two orders of magnitude thicker than they are wide. This is attributed to the high anisotropy of the interatomic bonding forces, which is reflected in the fourfold difference between the LTEC values. The LTEC values are measured in the basal plane and along the c axis of the hcp lattice of this phase.