Vol 124, No 6 (2023)

The work is devoted to the study of the possibility of obtaining hard magnetic materials during the crystalli-zation of amorphous alloys of the Fe–Co–Cr–B–Si system. The influence of boron content in alloys on their glass-forming ability was analyzed. The structure and phase transformations in alloys during heating were ana-lyzed using X-ray diffraction and transmission electron microscopy. Influence of the phase composition on the magnetic properties of the alloys has been established. It is shown that the formation of a nanosized eutectic structure [α + (Fe, Cr)3B] during the crystallization of an amorphous matrix is promising for development of new hard magnetic materials.

To produce an Al2Au+Cu ingot, a mixture of Al2Au and copper intermetallic powders was compacted and then melted in an argon atmosphere. The study of the ingot structure revealed the formation of brightly colored regions of the intermetallic phase Al2Au, which are located in a matrix of intermetallic AlAu. Thin veins enriched with copper were found inside the AlAu matrix. The optical characteristics of the resulting triple compound were measured. Microindentation of intermetallic phases was carried out, the values of their microhardness and contact modulus of elasticity were determined

Grain-boundary diffusion of Co in ultrafine-grained Nb processed by severe plastic deformation by high-pressure torsion has been studied by layer-by-layer radiometric analysis. Coefficients of grain-boundary diffusion for several temperatures have been determined. It is shown that diffusion along grain boundaries proceeds much faster than in coarse-grained niobium with relaxed boundaries, which is explained by the formation of "non-equilibrium" grain boundaries under the severe plastic deformation, which are the paths of ultrafast diffusion. Recovery processes occur in non-equilibrium grain boundaries under heating, due to which their properties approach to those of conventional high-angle boundaries in the coarse-grained material.

The influence of cold rolling with degrees of 85, 90% on the structural and textural state, microdurometric and elastic properties of hardened biocompatible -titanium alloys (at.%) Ti-26%Nb-3%Zr, Ti -26%Nb-5%Zr, Ti-26%Nb-6%Zr, Ti-26%Nb-3%Zr-1%Sn, Ti-26%Nb-3%Zr-1%Sn-0.7Ta . It is shown that an increase in the degree of deformation during cold rolling contributes to the formation of a more pronounced two-component texture {001}, {112} an increase in microhardness and a decrease in the values ​​of the elastic modulus in the rolling plane . A good agreement between the calculated and experimental values ​​of the modulus of elasticity of alloys in the quenched and cold-rolled states has been established.The influence of alloying and anisotropic state of alloys (through the molybdenum equivalent and the Zener anisotropy factor, respectively) on the level of their microhardness, contact modulus of elasticity E, including the difference in E in different sections of a cold-rolled sheet, is considered. It has been established that the minimum average value of Е=51±2 GPa in the rolling plane is given by the Ti-26Nb-3Zr alloy rolled with ε=90%, and the minimum level of average values Е (52±2 GPa in the rolling plane and 62±1 GPa in cross section) is typical for the Ti-26Nb-3Zr-1Sn alloy after rolling with ε= 85%

Samples cut from a disk blank of Russian granulated nickel-based superalloy VZH178P were tested for tensile strength at room temperature and long-term creep at temperature of 750 °C. Transmission electron microscopy showed that, in both cases, stacking faults and microtwins formed during plastic deformation of the alloy. During long-term creep at 750 °C, the alloying elements Cr, Co, Mo, and W segregate on the stacking faults, leading first to the formation of Suzuki atmospheres and then to the nucleation and growth of TCP particles with stoichiometry (Co,Cr)3(Mo,W).

In this work, we studied the effect of annealing temperature on the structure and texture, as well as the mechanical properties of the austenitic stainless steel AISI 316. Initially, the program material was subjected to cold rotary swaging with a reduction of 95%. Studies showed the formation of the structure and texture gradient during preliminary plastic deformation. Annealing at low temperatures (500-600°C) provoked polygonization, while the intensity of the and texture components remained unchanged. After annealing at 700°С, the onset of recrystallization was observed only in the subsurface layers of the rod. As a result of annealing at 800–900°C, static recrystallization occurred over the entire cross section of the rod, which caused dissipation of the texture gradient. Annealing at temperatures of 400–600°C was accompanied by an increase in the strength and hardness characteristics. Meanwhile, ductility also increased with the annealing temperature. Annealing at 700°C resulted in softening of the program material almost to the level of the initial cold-swaged state and a significant increase in ductility up to 16%.

The influence of multidirectional isothermal forging on the grain structure and secondary phase particles of solidification origin and dispersoids in Al–4.9Mg–0.9Ni–0.9Fe–0.2Zr–0.1Sc alloy has been studied. The finite element simulation was used to analyze a strain distribution in the sample during forging in a die. A proposed method considered the influence of friction and the changes in a strain rate to recalculate true stress-strain curves for multidirectional forged alloy. An increase in a number of forging cycles at a temperature of 350°C ensured a twice decrease in a mean size of the particles of solidification origin, provided a mean grain size of 1.3 ± 0.2 μm, and insignificantly changed the size of dispersoids. The isothermal multidirectional forging increased the yield strength of the alloy by 60%, tensile strength by 20%.