This paper presents the results of investigation of alloys Hf–45% Ti and Hf–70% Ti structures which were formed under different kinetic conditions of the β → α (bcc → hcp) polymorphic...

Differential scanning calorimetry, X-ray diffraction analysis, transmission electron microscopy, and microhardness measurements are used to study the reverse ω → α phase transformation in titanium and zirconium, which were subjected to deformation in a Bridgman chamber under close loading conditions in order to obtain additional data on the degree of stability of the studied metals. It was found that, despite the qualitative similarity of heat release processes that occurred in the metals under study, which are recorded by differential scanning calorimetry, the reverse phase transformation in titanium, in contrast to that in zirconium, is realized at lower temperatures and within narrower temperature range over the whole range of preliminary true strain. It was found that the characteristics, such as the temperature of the onset of reverse phase transformation and value of released thermal energy are stabilized on reaching the certain true strain (е ≈ 9), when the mixed nano- and submicrocrystalline structure forms in both the metals, in which deformation defects and extensive interfaces make the maximum energy contribution to the system.

The structure of a hafnium crystal grown by the method of floating zone melting which underwent upon cooling the β → α (bcc → hcp) polymorphic transformation has been studied using the metallography,...

The study of unstable plastic flow in porous steel 316L samples after compression deformation at room temperature with different strain rates was carried out. The samples were obtained from ASTM F3184 medical grade steel powder by digital metallurgy using a Renishaw AM 400 laser 3D printer. Serrations on the stress-strain curves and strain localization bends were found, which were associated with the Portevin-Le Chatelier effect and testified instability of the plastic flow of the material under the deformation process. Deformation twins were observed in the structure of deformed samples.

Phase transitions in the Co-rich part of the Co–Al–Nb–Mo phase diagram are studied by energy dispersive spectroscopy (EDS), X-ray analysis, transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) measurements. The obtained results were compared with the results for alloys of the binary Co–Al and ternary Co–Al–Nb, and Co–Al–Mo systems. Formation of the intermetallic phase with the L1₂ structure was found in a range of alloys with 10 at.% Al, 2–9 at.% Nb, and 3–7 at.% Mo. Intermetallic compound Co₂Nb, Laves phase with the different chemical composition and crystal structure (C14 and C36) was detected in the Co–Al–Nb and Co–Al–Nb–Mo samples after vacuum solution treating at 1250 °C for 30 h.