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Zinc single crystals have been shocked by planar impact along the [ 10 1 ¯ 0 ] axis as well as in the off-axis direction. The evolution of compression waves has been analyzed from the free surface velocity profiles of zinc single crystal samples. A slip on the primary system is activated by impact loading in directions making angles of θ = 17°–64° with respect to the [ 10 1 ¯ 0 ] axis. The phenomenon of the formation of two plastic compression waves propagating at different velocities is observed in samples oriented at angles of 53° and 64°. The spall fracture of single crystal zinc samples oriented in different directions has been measured. It is shown that the highest value of spall strength is recorded along the highly symmetric axis of the crystal. The experimental results presented are consistent with the data published in the scientific literature on beryllium and magnesium and confirm the important role of crystalline anisotropy in the process of inelastic deformation of single crystals. [ABSTRACT FROM AUTHOR] more...

Scanning and transmission electron microscopies are used to study the microstructure and phase composition of the surface layer of Zr–1% Nb alloy, which was subjected to treatment by nanosecond laser pulses. During laser treatment, a thin strengthened surface layer with the fine microstructure is found to form. The strengthening of the surface layer no less than 4 µm thick is proved to be due to the formed twin micropackets consisting of martensite nanolamellas and nano-sized ω-Zr phase. [ABSTRACT FROM AUTHOR] more...

An investigation is performed of the effect produced by the technological parameters of a complex procedure for obtaining 3D printing powder of a new Nikalin aluminum alloy during dispersion in a ball mill, with the subsequent spheroidization of particles while processing the plasma. [ABSTRACT FROM AUTHOR] more...

The industrial Ti–6Al–4V alloy, obtained almost in the single-phase α state by the thermomechanical treatment including hot rolling, is studied by the methods of X-ray diffraction analysis, optical and transmission and scanning orientation electron microscopy. It is revealed that the layered fine-grained microstructure in the plate's transverse section (TD) along the rolling direction (RD) is characterized both in the rolling plane (ND) and in the transverse section perpendicular to the RD by the texture selection and consistent distribution of globular α grains over the orientation Burgers relations and twinning orientations. The special crystallographic orientation of α grains and the mechanisms of generation of microtexture regions in the studied plate's transverse section (TD) of the alloy correlate with the similar data established for the plate in the plane (ND) and in the transverse section. The results obtained in three mutually orthogonal sections of the plate agree with each other, determining the texture of the globular α phase. [ABSTRACT FROM AUTHOR] more...

The microtexture and microstructure of the industrial Ti–6Al–4V alloy almost in the single-phase α state, obtained using the thermomechanical treatment including the hot rolling, are studied by the X-ray diffraction analysis method and optical and transmission and scanning electron microscopy. It is established that the layered fine-grained microstructure in the cross section of the plate perpendicular to the rolling direction is characterized by selection of equiaxed globular α grains that obey Burgers orientation relationships and twinning orientations. The revealed distributions of α grains over dimensions and crystallographic orientations in the plate's cross section are related to the peculiarities of distributions established for the plane of plate rolling. The structural mechanisms of generating the microtexture regions in the alloy are discussed. [ABSTRACT FROM AUTHOR] more...

The effect of nanosecond pulse laser processing of the Zr–1% Nb alloy surface of specimens in the annealed state and after their two-stage deformation treatment by abc-pressing and rolling has been investigated. The morphology of the modified surface of specimens is described using optical and scanning microscopy. Furthermore, the microrelief formed as a result of vaporization and melting of a thin layer of material subjected to laser processing is evaluated quantitatively. Durometric measurements were conducted to ascertain the hardness of the near-surface layer and the impact of laser-induced shock waves on its hardness. The electron backscattering diffraction (EBSD) analysis data were employed to describe the structure of the specimens in the near-surface layer. The influence of the initial grain size on the quality of the modified surface, as well as on the depth and hardening of the near-surface layers has been established. [ABSTRACT FROM AUTHOR] more...

The commercial Ti–6Al–4V alloy was obtained in an almost single-phase state, formed by finely dispersed globular α-grains with an average size of 12 μm, using thermomechanical processing, including hot rolling. The microtexture and structure of the alloy were studied using X-ray diffractometry and transmission and scanning electron microscopy, including orientation microscopy. It is found that for α-grains the Burgers orientation relationships are satisfied, and twin orientations are ensured in the rolling plane. A significant scattering of the crystallographic orientations of α-grains relative to each other (up to 10°–15°) is established for each group of close Burgers orientations as a result of plastic deformation by rolling at high temperatures. Clusters of microtexture regions in the layered microstructure of grains and the formation mechanisms and mutual crystallographic misorientations of microtexture regions and grains in the alloy have been identified. [ABSTRACT FROM AUTHOR] more...

The work is devoted to the study of the effect of multi-step heat treatment on the formation of the microstructure of the alloy of Al–Mg–Si series, alloyed with scandium and zirconium at the ratio of Mg/Si = 0.3. For this purpose, the base AlMgSi alloy, containing no scandium and zirconium, as well as its modification AlMgSiScZr with additions of these elements were cast. Multi-step heat treatment of AlMgSiScZr alloy consisted of four steps of annealing: at 550°C for 8 h + at 440°C for 8 h + at 500°C for 0.5 h + at 180°C for 5 h. For AlMgSi alloy, it included two steps: at 550°C for 8 h + at 180°C for 5 h. The microstructure of AlMgSiScZr alloy was studied in the cast state, as well as after each step of heat treatment by scanning and transmission electron microscopy, while AlMgSi alloy was studied in the cast state and after the final heat treatment. After each step of heat treatment, the microhardness of the studied alloys was measured. It was found that during cooling of the ingot, in the alloys under consideration coarse intermetallics of Fe2Mg7Si10Al18 type were formed, which partially were dissolved during subsequent heat treatment. At the same time, in the alloy with scandium and zirconium additives, particles that can be attributed either to (AlSi)3ScZr or to the τ (phase) of AlSc2Si2 are present at the intergranular boundaries. No traces of intermittent decomposition of the scandium supersaturated solid solution during cooling of the ingot were found. Heat treatment at 550°C for 8 h + at 440°C for 8 h leads to the appearance of a phase that can be both AlSc2Si2 and Al5SiZr2, while no (AlSi)3ScZr nanoparticles are formed. Heating at 500°C for 30 min enables complete dissolution of the magnesium-containing particles. At the final step, β" (Mg5Si6) particles are formed in the investigated alloys, while scandium has no significant effect on their formation. [ABSTRACT FROM AUTHOR] more...

Monolith and bulk-structured samples of different densities have been obtained using selective laser melting on a Realizer SLM 100 3D-printer intended for metals. Their quality and structure have been estimated via metallography and scanning electron microscopy. The correlation has been established between the parameters of synthesis, namely, between the intertrack distance and layer thickness at a laser power of 200 W, on the one hand, and structural characteristics, on the other. Based on the experimental results, the optimum operating parameters of a 3D-printer were found to obtain the Al–Cu–Mg–Si samples with dispersed structure and high mechanical properties. The features of the synthesis of bulk-structured samples with cubic geometry of plotting have been studied, and the types of defects that affect the quality and mechanical properties of samples have been determined. [ABSTRACT FROM AUTHOR] more...

We present the results of comparison of the deformation behavior and the collapse pattern of hollow cylindrical shells made of an Al–Zn–Mg–Cu alloy subjected to different pre-deformation heat treatment that were loaded by the sliding detonation in two modes differing in the duration of the shock wave pulse. It has been shown that at the same power of explosives, the convergence scenario of shells made of the studied alloy depends slightly on the duration of the shock wave pulse, which is set by the design features of the experimental setup. It has been established that the phase composition determined by the heat treatment mode strongly affects the convergence rheology. It has been shown that multiple spalling is formed in an annealed shell, while a quenched shell exhibits complete and steady convergence until it forms a solid cylinder. Light optics, scanning electron microscopy, and transmission electron microscopy have been applied to study the evolution of the structure of cylindrical shells. The different scenarios of convergence are determined by the presence or absence of nuclei of brittle fracture that are intermetallic phases, whose number, size, and nature are controlled by the initial heat treatment of the alloy. [ABSTRACT FROM AUTHOR] more...

Using high-resolution scanning and transmission electron microscopy methods, the morphological and size characteristics of the structural components of the composites synthesized on the basis of aluminum with a graphene microadditive in a commercial aluminum melt under a layer of molten salt are studied. An experiment on the dynamic compression of a composite by the Kolsky method was performed, the evolution of a cast structure during high-rate deformation is studied, and mechanical characteristics in the range of deformation rates έ = 1.8–4.7 × 103 s–1 were measured. The dynamic characteristics of the composite were measured under conditions of loading with planar shock waves (έ = 5 × 105 s–1) for the first time. The dynamic properties of the composite are compared as functions of the graphene content in the aluminum matrix. [ABSTRACT FROM AUTHOR] more...

The evolution of the structure and phase composition of the Al–Zn–Mg–Fe–Ni alloy (nikalin) during severe plastic deformation by high pressure torsion and annealing has been investigated using high-resolution TEM techniques. The deformation of the quenched alloy has been found to result in a submicron composite comprising an Al matrix and various fine aluminides. The severe structural refinement takes place along with phase transformations, which dissolve the metastable Al3Zr-phase particles and cause the nanosized strengthening phases Т (Al2Mg3Zn3) and η' (MgZn2) to precipitate from the Al solid solution which has been supersaturated in result of quenching and deformation. Nikalin has been determined to retain its submicrocrystalline state during low-temperature annealing (200°C, 4 h) due to the barrier effect of fine hardening phase particles, fixing grain boundaries. High-temperature heating to 400°C for four hours transfers nikalin to the overaged state, in which it is characterized to consist of a recrystallized matrix with grains 2–3 µm in size, eutectic micron-sized aluminides, and stable Al2Mg3Zn3 and MgZn2-phase particles with sizes of no more or equal to 500 nm. [ABSTRACT FROM AUTHOR] more...

Structural and phase transformations in a commercial multicomponent aluminum–lithium alloy have been studied electron-microscopically upon storage after mega-plastic deformation by high-pressure torsion. It has been shown that the arising deformation structure of the alloy is unstable, and upon subsequent storage at room temperature it is transformed via a complex reaction of in situ recrystallization and decomposition of the supersaturated solid solution. The character of the transformation is determined by the regime of the previous mega-plastic deformation and by the duration of the storage. [ABSTRACT FROM AUTHOR] more...

The structural and phase transitions in the Al–Li–Cu–Mg–Zr–Sc–Zn alloy subjected to megaplastic torsional deformation under high pressure in the process of low-temperature annealing at 150°C have been studied by electron microscopy. It has been shown that the character of the nanocrystalline structure formed in the annealing process is determined by the specific features of the earlier existing deformation structure and demonstrates structural heredity. The effect produced by the structural state of the annealed alloy on the level of mechanical properties (hardness, plasticity, elasticity modulus, stiffness) is discussed. [ABSTRACT FROM AUTHOR] more...

Abstract: This paper presents the results of a study of structural transformations and the main tribological properties (coefficient of friction and wear rate) of Al-2.2 Li and Аl-3.1 Сu-2.0 Li-0.1 Zr (wt %) alloys. Optical metallography and transmission electron microscopy have been used to examine the alloy structure after heating and friction. Tribological tests of the alloys in pair with steel are carried out by sliding friction using a pin-on-plate scheme during reciprocating motion of a sample. The sliding velocity is 0.07 m/s and the load is 294 N. Friction is carried out in air and in a nitrogen gas at room temperature. Alloying of the Al-Li alloy with copper (3.1 wt %) and zirconium (0.1 wt %) is shown to significantly increase the wear resistance, enhance the frictional hardening, and reduce the friction coefficient of the alloys. The positive effect of this alloying on the tribological properties of the Al-Li alloy is caused by friction-induced severe strain hardening. A high-strength nanocrystalline structure consisting of a mixture of matrix crystals and a metastable δ' (Al3Li) phase is formed in a surface layer to 10 μm thick. Planar dislocation slip is observed in both alloys. This sliding mechanism is assumed to be related to the low (f ~ 0.25) coefficient of friction of both alloys. Artificial aging carried out under different four regimes increases the hardness of alloys, but significantly reduces their resistance to wear. This paper offers an explanation for the effects obtained. [ABSTRACT FROM AUTHOR] more...

The structural and phase transformations in the Al-Li-Cu-Mg-Zr-Sc-Zn alloy have been studied by the electron microscopy after the aging for the maximum strength and in the nanostructured state after severe plastic deformation by high-pressure torsion. It has been shown that severe plastic deformation leads to the formation of a nanostructured state in the alloy, the nature of which is determined by the magnitude of deformation and the degree of completeness of the dynamic recrystallization. It has been established that deformation also causes a change in the phase composition of the alloy. The influence of the structural components of the severely deformed alloy on the level of mechanical properties, such as the hardness, plasticity, elastic modulus, and stiffness has been discussed. [ABSTRACT FROM AUTHOR] more...