The influence thermomechanical treatment processing parameters on mechanical properties of metastable β -titanium alloy VT47 hot rolled sheets is investigated. It is shown that the alloy is effectively hardened by low-temperature thermomechanical treatment (LTMT) after cold rolling with plastic deformation from 15 to 65

The structure of the (Pr 1 – x Dy x ) 13.4 (Fe 1 – y Co y ) 79.1 B 7.5 and (Pr 1 – x Dy x ) 12.7 (Fe 1 – y Co y ) 87.2 B 10.1 alloys in the as-cast state after conventional solidification and after rapid quenching by melt spinning is studied. Phase analysis shows that, in the case of alloys with a higher boron content, the content of weakly magnetic phases increases. Differential scanning calorimetry allowed us to identify the magnetocaloric effect in the usually cast alloys at their Curie temperature and the crystallization and recrystallization processes of amorphous phase in the rapidly quenched alloys. The alloys in the initial cast state are characterized by a low coercive force of 0.8–8 kA/m (10–100 Oe). The rapidly quenched alloys, in which 2-14-1 main magnetic phase inclusions (REM 2 (Fe, Co) 14 B) are small (~10 μm) and well isolated from each other by an amorphous phase, are characterized by a high coercive force of 1600 kA/m (20 kOe).

Questions of structure formation for “self-hardening” metastable pseudo-β-titanium alloys after deformation and heat treatment are considered. Information is provided for variation of the phase composition in various alloys of this group. Questions of morphology variability and topology of α-phase particles, i.e., the main hardening phase in “self-hardening” metastable β-titanium alloys, as well as the relationship of structural parameters with chemical composition and versions of thermomechanical treatment are considered in detail. The article discusses some of the latest advances in formation of different secondary α-phase morphology and topology, as well as estimates of prospects for further development in this area of research.

The effect of copper alloying on the coercive force and the residual induction of sintered materials (Pr 0.53 Dy 0.47 ) 13 (Fe 0.64 Co 0.36 ) res Cu x B 6 ( x = 0–3 at %) annealed at various temperatures is considered. The dependences of coercive force H cI and residual induction B r on the copper content are found to be nonmonotonic. This fact is explained by that alloying with copper leads to a change in the phase composition, which is accompanied by an increase in the coercive force and the residual magnetization of the alloy, while a change in the chemical composition and the thickness of intergranular interlayers upon copper alloying leads to a decrease in the values of H cI and B r as the copper content increases.

Actual information is provided about formation of structural defects typical for highly-alloyed titanium alloys, i.e., α-phase precipitate-free zones. The effect of these defects on the mechanical properties of pseudo β-titanium alloys is considered. The structure is studied for a new pseudo β-titanium alloy VT47 and a correlation is established for mechanical properties and presence of these zones within the structure. x-Ray microanalysis is used for an analytical study of the local chemical composition of alloy VT47 that makes it possible to establish that formation of precipitate-free zones the main and most important features is not connected with the different chemical composition in in the test ranges of alloying element concentration for the zones themselves and areas adjacent to them.

The effect of annealing of a (Pr 0.41 Ce 0.12 Dy 0.47 ) 13.46 (Fe 0.64 Co 0.36 ) 80.3 B 6.24 alloy at 1000°C on its microstructure and the properties of sintered magnets made of it has been studied. In the annealed state, the composition of the main magnetic phase (Pr,Dy) 2 (Fe,Co) 14 B changes sharply (dysprosium content changes), the residual induction of the sintered magnets made of the annealed alloy increases by 6%, and the coercive force determined from magnetization increases by 8.5%. The volume content of the main magnetic phase R 2 (Fe,Co) 14 B in sintered magnets (Nb,Dy)–(Fe,Co)–B and (Pr,Dy)–(Fe,Co)–B is found. The content of this phase in neodymium-based magnets is approximately half as much.

The structure, the phase composition, and the distribution of alloying elements in the structure of temperature stable hard magnetic materials of the REM–Fe–Co–B system (REM = rare-earth metals), which are prepared under different manufacturing conditions, namely, at different sintering temperatures and times, have been studied. The phase composition, the local chemical composition of phases, the volume fraction of pores, and the manufacturing conditions that allow one to prepare the structure ensuring high magnetic properties have been determined.

It has been shown that the alloying of sintered Nd-Dy-Fe-Co-B magnets with praseodymium leads to an increase in their temperature stability at temperatures of 20–100°C. This effect is explained by the redistribution of dysprosium ions in the crystal lattice of the base (Nd, Pr, Dy)2(Fe, Co)14B magnetic phase, namely, by their transition from 4f to 4g sites.

The effect of copper on the properties of magnets (Pr 0.52 Dy 0.48 ) 13 (Fe 65 Co 0.35 ) 80.3 − x Cu x B 6.7 ( x = 0–10) has been studied. Alloying with copper is shown to decrease the sintering temperature and to increase the content of the principal (Pr,Dy) 2 (Fe,Co) 14 B magnetic phase. For compositions with x = 1.3–3.3, copper is found to affect the value and sign of the temperature induction coefficient (TIC). It is shown that the effect of copper on the TIC is determined by the substitution of copper ions for iron ions in lattice sites, which are coupled via an antiferromagnetic exchange interaction.

Pr-Dy-Gd-Fe-Co-B magnets with low temperature induction coefficients are studied. It is shown that the temperature induction coefficient of a material can be calculated from its composition in the framework of the molecular-field approximation using a model of five magnetic sublattices. The calculated and experimental data are compared.

Effect of heat treatment (HT) in the temperature range from 400 to 1000°C on the properties of sintered (Pr1 − x Dy x )12 − 17(Fe1 − y Co y )balB5 − 15 (x = 0−0.73 and y = 0.15−0.87) magnets is studied. It is shown that, depending on the cobalt and boron contents in the material, its composition and the dependence of H cI on heat treatment conditions change. In the HT temperature range 700–900°C, an H cI minimum is found: the “depth” of the minimum increases with increasing cobalt content. The minimum of H cI is reversible; i.e., after HT at 1000°C, the coercive force increases to the value corresponding to the composition of the material whatever the temperature of preliminary HT. A model that explains the dependence of H cI of the material on the HT conditions by a diffusion redistribution of boron between the basic R 2F14B (2-14-1 intermetallic) and RF 2, RF 4B, RF 3B2, and RF 2B2 phases (with R = Pr + Dy, F = Fe + Co) is suggested.