Vol 124, No 4 (2023)

The electrical resistivity, magnetic, and galvanomagnetic properties of the cast and rapid melt quenched Mn3Al Heusler alloy have been studied. Rapid melt quenching was found to result in changing the microstructure of the Mn3Al alloy, which leads to substantial changes in its electronic transport and magnetic
properties. It was suggested that for the cast and rapid melt quenched Mn3Al alloy frustrated antiferromagnetic and almost compensated ferrimagnetic state could appear, respectively. It is shown that the preparation and treatment of the Mn3Al compound plays a substantial role in the formation of its electronic and magnetic
characteristics

The effects of heat treatment on the structure and magnetic properties of the 80NHS grade permalloy produced by selective laser melting (SLM) of gas-atomized powder are presented in comparison with the properties of the rolled 80NHS alloy. Ring samples either produced by SLM or machined from rolled metal have been studied. It has been established that the magnetic properties of the SLM samples are inferior to the properties of samples produced by thermomechanical processing because the structure of the additively
manufactured alloy is characterized by fine grains and a large number of nonmetallic inclusions.

The parameters of the hyperfine interaction of 57Fe nuclei in single crystals of iron borate FeBO3 and its isostructural solid solution Fe0.91Ga0.09BO3 have been determined by Mössbauer spectroscopy. A theoretical model has been developed to describe resonant transitions of iron nuclei in the approximation of a combined magnetic dipole and electric quadrupole hyperfine interaction, taking into account the statistical distribution of Ga and Fe over octahedral positions in the Fe0.91Ga0.09BO3 crystal. It has been established that even a low Ga concentration leads to a significant change in the hyperfine structure of the 57Fe nuclei in
FeBO3, which manifests itself in the appearance of additional components in the Mössbauer spectra of the Fe0.91Ga0.09BO3 single crystal.

In the Zr–Sn–Nb–Fe quaternary alloys, the nature and evolution of the second phase particles (SPPs) is critical to the performance of the alloy in the extremely deteriorative environment. The main aim
of this review consists in summarizing the fundamental results of the identification and characterization of the SPPs in the Zr–Sn–Nb–Fe alloys. Emphasis was placed on the importance of composition, identification,
crystallographic structure, formation mechanism, and state and stability of several SPPs in these alloys. Identical compositions in ternary Zr–Nb–Fe intermetallics have been identified as C14 HCP Zr(Nb,Fe)2 or
C15 FCC (Zr,Nb)2Fe structure. Zr(Nb,Fe)2 is often reported, while, the cubic phase (Zr,Nb)2Fe is easily distinguished.
The reliability of R* parameter, which is specified by Nb/Fe physical ratio in determining the SPPs types in different composition range of Zr–Sn–Nb–Fe alloys, is discussed with reasons. The influence and the role of O and Cr in the formation and stability of ternary Zr–Nb–Fe intermetallics are also clarified. Finally, thermodynamic stability of SPPs was also taken into consideration in the current review.

It is shown that application of the crystallographic theory of martensitic transformation instead of
the phenomenological one allows proper understanding of the mechanism of martensitic transformation in
crystallographic analysis and computing, in addition to the previous characteristics, a new important characteristic,
that is, the relaxation rotation of martensite crystallites to obtain the invariant plane. It is demonstrated
that the angle of relaxation rotation is most strongly dependent on the crystallographic systems of the original and final phases, as well as on the lattice parameters of these phases. It has been discovered that scattering
of the texture peaks of martensite, determined as the integral half-width of the texture maximum, is in linear proportion to the angle of relaxation rotation of martensite crystals.

Composites with an aluminum matrix are relevant materials for research, since they are superior to conventional materials in their mechanical characteristics and can be used in various industries. In this work, the method of molecular dynamics is used to study the interdiffusion at an Al/Cu mixing interface
under compression combined with the shear deformation. Molecular dynamics tensile tests of the obtained
composite have been performed after combined compression to different strains. The deformation scheme
used in this work is a simplified scenario that was previously experimentally performed to obtain Al/Cu composites.
It has been shown that compression combined with the shear deformation is an effective way to obtain
a composite structure. It has been found that under deformation Cu atoms more easily diffuse into an Al block
than Al atoms diffuse into a Cu block. Tensile tests performed after the combined compression show that fracturing
occurs in the aluminum part of the composite; therefore, the Al/Cu mixing interface is stronger than
the pure aluminum part.

The formation of a crystal structure and properties of a welded joint between a porous stainless steel plate and a solid plate of greater thickness with the use of nanomodifying additives has been experimentally investigated. To obtain a high-quality butt joint of the plates, the end layer of the solid plate was found to have been penetrated. The laser beam axis is shifted from the boundary of the plate joint by some distance, which is necessary to compensate the (material of) metal during the melting of the porous plate. The application of
nanomodifying additives reduces the grain size of the weld structure, which, in turn, has a positive effect on the mechanical properties of the resulting joint. The results of tensile strength tests have shown that the failure
of nanomodified samples, unlike unmodified ones, occurred only in the main porous metal. The average value of the tensile strength is 89.5 MPa.

A comparative analysis of semi-empirical methods based on the Kohler, Bonnier, and Toop models for predicting the surface tension (ST) of ternary systems has been performed. Surface tension–concentration dependence calculations have been carried out in the indium–tin–lead and indium–tin–gallium systems. The ternary indium–tin–lead system is characterized by the fact that the excess surface tension isotherms of all the side binary melts are symmetrically shaped with respect to the equimolar composition, and such systems are called symmetric. In the ternary indium–tin–gallium system, the excessive surface tension isotherms of side binary indium–gallium and tin–gallium systems have pronounced asymmetry with respect
to the equimolar composition, and such systems are called asymmetric. It has been shown that a method based on the Kohler model rather precisely describes the concentration dependence of the surface tension of
symmetric ternary systems. However, this method does not predict the concentration dependence of the surface tension of asymmetric systems. It has been revealed that the Bonnier and Toop models can predict the
surface tension–concentration dependence for asymmetric ternary systems with strong asymmetry in the excess surface tension isotherms of two side binary systems independently of the degree of complexity in these isotherms within overall error of experiment.