Zinc single crystals have been shocked by planar impact along the [ 1010 ] 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 theta = 17 degrees-64 degrees with respect to the [ 1010 ] axis. The phenomenon of the formation of two plastic compression waves propagating at different velocities is observed in samples oriented at angles of 53 degrees and 64 degrees. 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.

Scanning and transmission electron microscopies are used to study the microstructure and phase composition of the surface layer of Zr–1

Zinc single crystals have been shocked by planar impact along the [101¯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 [101¯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.

The deformation behavior of the thick-walled hollow cylindrical shells made of an AMg6 alloy (6.1 Mg, 0.6 Mn, 0.1 Ti, 0.2 Si, and Al for balance, wt %) loaded using an 8-point initiation scheme of an attached explosive has been considered. The intensity of explosive loading is controlled by an amount of explosives. It has been established that different scenarios for convergence of the shells are observed depending on the intensity of impact and the geometric parameters of the shells. The conditions for the formation of the spallation inner layers have been determined, the structural evolution under high-speed radial deformation and that along the length of the shells together with the change in the radial hardness of the shells have been studied. X-ray radiography of the dynamics of the deformation processes in the shells has been performed for different time intervals. The speeds of the motion of the outer and inner layers of the shells and their deformation rates for different amounts of explosives have been determined.

Рассмотрены динамические свойства объемно-структурированных образцов с разной топологией сетчатых структур из алюминиевого сплава АК6, синтезированных селективным лазерным сплавлением. Испытания проведены при квазистатических скоростях деформации 102 ÷ 103 с‒1 методом Кольского с использованием разрезного стержня Гопкинсона. Построены диаграммы деформирования, и определены значения условного предела текучести и предела прочности. Проведено сравнение результатов измерения свойств образцов с разной топологией сетчатых структур — кубические типа ГЦК и ОЦК и трижды периодических поверхностей минимальной энергии типа гироид. Исследовано влияние геометрических характеристик гироидов (размер ячейки, толщина стенки) на прочностные свойства образцов. Показано, что при одной и той же плотности материала гироиды обладают повышенными характеристиками. Сетчатые металлические материалы, полученные аддитивной технологией, могут быть использованы в технике для уменьшения массы конструкций и ослабления разрушающих высокоэнергетических механических воздействий. Dynamic properties of volume-structured samples with different topology of mesh structures made of AK6 aluminum and synthesized by selective laser melting are considered. Tests are carried out at quasistatic strain rates of 102 ÷ 103 с‒1 by the Kolsky method using a split Hopkinson bar. Strain diagrams are constructed, and the values of the conditional yield strength and tensile strength are determined. The results of measuring the properties of samples with different topology of mesh structures of FCC and BCC types and triply periodic surfaces of minimum energy of the gyroid type. The effect of the geometric characteristics of gyroids (cell size and wall thickness) on the strength properties of the samples is described. It is shown that gyroids have improved characteristics at the same material density. Mesh metal materials obtained by additive technology can be used in engineering to reduce structural mass and destructive high-energy mechanical effects.

The effect of nanosecond pulse laser processing of the Zr–1

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 mu m thick is proved to be due to the formed twin micropackets consisting of martensite nanolamellas and nano-sized omega-Zr phase.

The paper considers the deformation behavior of a cylindrical shell made of industrial wrought magnesium alloy MA-14 (Mg 93 wt

Heat treatment of materials, including-in particular-two-stage T6I6 treatment, enables the nucleation of precipitates with a two-phase structure: core and shell. The above-mentioned treatment can be used to harden materials by selecting suitable treatment parameters and the chemical composition of the material that initiates a selective diffusion of the alloying elements. In this paper, tests of the T6I6 treatment were carried out on the EN AW-2024 alloy. The aluminium alloy was subjected to T6I6 treatment, and then the element distribution map was examined within the precipitate using the EDS method. The mechanical properties of the precipitate were tested using the nanoindentation method, and the kinetics of the formation of the precipitate were analysed using DSC. The impact of two-phase precipitates on the mechanical properties was determined through a static strength test, whereas the impact of the structure on the above-mentioned mechanical properties was determined based on HR-TEM observations. The results of the study confirmed the formation of a precipitate with a two-phase structure (shell; core) in the EN AW-2024 alloy, as well as the kinetics of their formation as a function of the parameters of the T6I6 process, such as temperature, duration and cooling rate. Strength tests confirmed an increase in the strength of the alloy to Rm = 520 MPa, with elongation remaining the same at A = 13.2%. HR-TEM observations, in turn, proved that the shell forming on the core is coherent with solid solution alpha, which means that the hardening of the alloy may occur as a sum of the Mott-Nabarro, Friedel and Ashby-Orowan mechanisms.

The paper presents a comparative study of the erosion wear resistance of WC-10Co4Cr, Cr3C2-25NiCr and martensitic stainless steel (SS) coatings deposited onto an AlSi7Mg0.3 (Al) alloy substrate by high-velocity air‒fuel (HVAF) spraying. The influence of the abrasive type (quartz sand or granite gravel), erodent attack angle, thickness, and microhardness of the coatings on their and Al substrate’s wear resistance was comprehensively investigated under dry erosion conditions typical for fan blades. The HVAF-spraying process did not affect the Al substrate’s structure, except for when the near-surface layer was 20‒40 μm thick. This was attributed to the formation of a modified Al-Si eutectic with enhanced microhardness and strength in the near-substrate area. Mechanical characterization revealed significantly higher microhardness values for the cermet WC-10Co4Cr (~12 GPa) and Cr3C2-25NiCr (~9 GPa) coatings, while for the SS coating, the value was ~5.7 GPa. Erosion wear tests established that while Cr3C2-25NiCr and SS coatings were more sensitive to abrasive type, the WC-10Co4Cr coating exhibited significantly higher wear resistance, outperforming the alternatives by 2‒17 times under high abrasive intensity. These findings highlight the potential of HVAF-sprayed WC-10Co4Cr coatings for extending the service life of AlSi7Mg0.3-based fan blades exposed to erosion wear at normal temperatures.

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.

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.

Composites based on Al-Fe alloys and reinforced with three-layer graphene sheets were synthesized "in situ" under a layer of molten salts. Composites containing 0.12 wt.% graphene were subjected to severe plastic deformation via high-pressure torsion. SEM and TEM were used to study the morphological and size characteristics of the composite structure in the as-cast and deformed states. Herein, it is shown that severe plastic deformation leads to the deformation-induced dissolution of iron-containing aluminides with the formation of a supersaturated Al solid solution with a submicrocrystalline structure. The hardness and electrical properties of the graphene composites were measured in different structural states and compared to the characteristics of the matrix alloy.

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.

Composites based on Al-Mg alloy, reinforced with graphene nanofilms, were obtained by in situ synthesis under a layer of salt melt. Using SEM and HRTEM, the morphological and dimensional characteristics of the structural components of composites with different contents of graphene were studied. An experiment on dynamic compression of composites by the Kolsky method was carried out, dynamic properties were measured, and the evolution of a cast structure during high-speed deformation was considered. For the first time, the dynamic properties of composites under loading by plane shock waves have been determined. The dynamic properties of aluminum matrix composites are compared depending on the properties of the non-reinforced alloy.

The structure and mechanical properties of composites consisting of a metal matrix based on aluminum and its alloys of different compositions (AA-3003 and AA-5154) and graphene synthes sized in situ under a layer of molten salts were investigated depending on the chemical composition and grain size of the matrix. Aluminum matrix composites of three compositions were studied in as-cast coarse-grained, deformed fine-grained (grain size < 1 mm), and deformed sub microcrystalline (grain size < 1 μm) states in order to compare the structural characteristics of composites with different grain sizes. The composites were subjected to deformation with a split Hopkinson (Kolsky) bar and to dynamic-channel angular pressing. The hardness and dynamic mechanical properties of the composites were measured at strain rates ε˙ from 1.8 − 4.7 × 103 to 1.6 − 2.4 × 105 s−1. It was found that grain refinement induced a sharp increase in the hardness of composites with various compositions (by a factor of 1.6–2.6). A correlation of the elastic-plastic properties of the aluminum matrix composites with the grain sizes and chemical compositions of the matrices was established. A transition from coarse-grained to sub microcrystalline structure was shown to improve the elastic-plastic properties on average by a factor of 1.5. It was proved that the reinforcing effect of graphene increased with the decreasing grain size of the matrix. Mechanisms of reinforcement of the aluminum matrix composites using graphene were proposed.

This paper identifies the mechanisms of phase and structural transformations during severe plastic deformation by shearing under pressure (high-pressure torsion) of an Al-Zn-Mg-Fe-Ni-based aluminum alloy depending on different initial states of the material (an ingot after homogenizing annealing and a rod produced by radial-shear rolling). Scanning and transmission electron microscopy are used to determine the morphological and size characteristics of the structural constituents of the alloy after high-pressure torsion. It has been found that, irrespective of the history under high-pressure torsion, fragmentation and dynamic recrystallization results in a nanostructural alloy with a high microhardness of 2000 to 2600 MPa. Combined deformation processing (high-pressure torsion + radial-shear rolling) is shown to yield a nanocomposite reinforced with dispersed intermetallic phases of different origins, namely Al9FeNi eutectic aluminides and MgZn2, Al2Mg3Zn3, and Al3Zr secondary phases. The results of uniaxial tensile testing demonstrate good mechanical properties of the composite (ultimate tensile strength of 640 MPa, tensile yield strength of 628 MPa, and elongation of 5%).

The method of high-resolution scanning and transmission electron microscopy was used to investigate the features of the formation of the structure and deformation behavior of a composite material based on aluminum with microadditions of graphene under severe plastic deformation by the dynamic channel-angular pressing method. It was found that an aluminum-graphene composite with a submicrocrystalline structure with the hardness 2.5 times higher than in the as-cast state forms in the deformation process. For the first time, the dynamic properties of the composite were measured under loading by plane shock waves at a speed of 5.0.10(5) s(-1). Comparison with the dynamic characteristics of a coarse-crystalline composite showed an increase in the dynamic elastic limit and dynamic yield stress by 1.8-2.0 times. (C) 2020 Elsevier B.V. All rights reserved.