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This article presents the results of experimental studies on the dynamic and static strength of commercial aluminum alloy 5056 manufactured by wire-arc additive manufacturing (WAAM). The main objective is to evaluate the utilization potential of this technology for manufacturing parts for operation under shock loads. The dynamic tensile strength of the material was investigated with a modified Kolsky method, implemented by a split Hopkinson pressure bar. A comparative analysis of the strength characteristics of materials manufactured by WAAM and conventional cold-rolling methods was carried out using a structurally temporal approach with the incubation time criterion. The results showed that the aluminum alloy obtained by WAAM demonstrates comparable strength levels to that of cold-rolled material. The findings suggest that WAAM can be a competitive alternative for producing high-strength aluminum alloys for operation under shock loads. [ABSTRACT FROM AUTHOR]

This study investigates the influence of various heat treatment regimes on the structure and microhardness of the aluminum alloy AlSi10Mg processed by the L-DED method. The study considers heat treatment regimes for solid solution in the temperature range of 500−540 °C with holding times of 30–120 min, as well as artificial aging regimes in the temperature range of 160−190 °C with holding times of 4–8 h. As a result of studying the structure and mechanical properties of the heat-treated samples, it became clear that the optimal regime can be considered the regime of 500 °C for 30 min followed by 190 °C for 6 h. This regime leads to the formation of a uniform structure with the breakage of the eutectic network into separate spherical silicon inclusions. The microhardness in this case is 90 HV, which is 55% higher than the initial state. Using TEM, it was established that the reason for the increase in hardness is the formation of nanoscale inclusions β″ (Mg5Si6). [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) have shown promise as materials with improved mechanical properties compared to traditional materials. Achieving the desired mechanical properties depends on the alloy composition, both in terms of percentage and elements. Laser directed energy deposition technology allows for the production of products with various complex geometries and dimensions (L-DED). It has been found that HEA FeCoNiCrCu alloys can be divided into regions with high concentrations of Fe + Co + Cr and Cu elements. Dendrite growth directions of HEA FeCoNiCrCu are (111) and (200), and the average microhardness is around 240 HV. All samples have cracks vertically along the height. Fine-grained and dendrite structures were observed. Cu-element is mainly found in cracks. The HEA FeCoNiCrCu alloy was compared with another HEA FeCoCrMnNi, successfully obtained by the same L-DED technology. Comparing the two HEAs FeCoNiCrCu and FeCoCrMnNi obtained with the same deposition parameters can help determine the impact of one element on the phase composition, microstructure and mechanical properties of the high-entropy alloy. Replacing the element Mn with Cu in HEA FeCoNiCrMn led to a shift in the dendrite growth from one to two predominant directions and a decrease in the average microhardness by 20%. [ABSTRACT FROM AUTHOR]

The temperature dependence of the mechanical properties of the CoCrFeNi medium-entropy alloy (MEA) manufactured by laser-directed energy deposition (L-DED) and additionally annealed at 1200 °C for 24 h was studied. The microstructure of the as-deposited alloy was represented by a single-phase face-centered cubic structure with coarse columnar grains and a high density of dislocation. Annealing resulted in the development of recrystallization and a reduction in dislocation density. The CoCrFeNi alloy produced by L-DED demonstrated mechanical properties comparable with those of the fine-grained equiatomic CoCrFeMnNi alloy, produced by casting followed by thermomechanical processing. Namely, as-deposited CoCrFeNi had a yield strength (YS) and ultimate tensile strength (UTS) of YS = 370 MPa and UTS = 610 MPa at room temperature, and YS = 565 MPa and UTS = 965 MPa at cryogenic temperature, along with a ductility of ~60%. Annealing resulted in a decrease in strength to YS = 180/350 MPa at 293/77 K. A quantitative analysis of various strengthening mechanisms showed that some strength increment of the as-deposited alloy was ensured by the high dislocation density formed during L-DED. [ABSTRACT FROM AUTHOR]

Features of microstructure, mechanical properties, and cracking behaviour of the René 80-type superalloy manufactured by laser-based directed energy deposition (DED-LB) have been investigated. Different cracking behaviours were observed in two thin walls fabricated by DED-LB under different conditions. The defect-free thin wall was produced at low power and scanning speed, while increasing energy input during the process led to intensive cracking. Two types of cracks that developed in the René 80-type superalloy were identified: solidification hot cracking and ductility-dip cracking (DDC), caused by σ-phase particles. It was found that transition from an equiaxed structure to a columnar one increased the susceptibility to crack propagation. [ABSTRACT FROM AUTHOR]

An important direction in the development of additive technologies is associated with the addition of ceramic particles (oxide, carbide, boride, and nitride ceramics) to metal powders. The prediction of the physical and mechanical characteristics of SiC-particle-reinforced composite materials (PRCMs) in comparison with experimental results was studied. A near-α Ti-4.25Al-2V titanium-alloy-based composite reinforced by 1 vol.% of SiC ceramic particles was produced using laser direct energy deposition. A multiscale modeling approach at the micro and macro levels was applied. At the micro level, the toughness and strength characteristics for a temperature interval of T = 20–450 °C were predicted using a representative volume element of PRCM with the nearly real shape of SiC particles. At the macro level, the features of plastic deformation and fracture of the PRCM were predicted by numerical modeling using the commercial software Digimat Student Edition ver. 2022.4 and Ansys Student 2023 R2. The addition of SiC particles was found to improve the physical and mechanical properties in the whole temperature range. The results of the numerical modeling were consistent with the experimental data (the deviation did not exceed 10%). The proposed approach for predicting the physical and mechanical properties of Ti-4.25Al-2V/SiC can also be used for other PRCMs obtained by laser direct energy deposition. [ABSTRACT FROM AUTHOR]

Extraordinary properties of two-dimensional materials make them attractive for applications in different fields. One of the prospective niches is optical applications, where such types of materials demonstrate extremely sensitive performance and can be used for labeling. However, the optical properties of liquid-exfoliated 2D materials need to be analyzed. The purpose of this work is to study the absorption and luminescent properties of MoS2 exfoliated in the presence of sodium cholate, which is the most often used surfactant. Ultrasound bath and mixer-assisted exfoliation in water and dimethyl sulfoxide were used. The best quality of MoS2 nanosheets was achieved using shear-assisted liquid-phase exfoliation as a production method and sodium cholate (SC) as a surfactant. The photoluminescent properties of MoS2 nanosheets varied slightly when changing the surfactant concentrations in the range C(SC) = 0.5–2.5 mg/mL. This work is of high practical importance for further enhancement of MoS2 photoluminescent properties via chemical functionalization. [ABSTRACT FROM AUTHOR]

In recent years, additive manufacturing of products made from 5000 series alloys has grown in popularity for marine and automotive applications. At the same time, little research has been aimed at determining the permissible load ranges and areas of application, especially in comparison with materials obtained by traditional methods. In this work, we compared the mechanical properties of aluminum alloy 5056 produced by wire-arc additive technology and rolling. Structural analysis of the material was carried out using EBSD and EDX. Tensile tests under quasi-static loading and impact toughness tests under impact loading were also carried out. SEM was used to examine the fracture surface of the materials during these tests. The mechanical properties of the materials under quasi-static loading conditions exhibit a striking similarity. Specifically, the yield stress σ 0.2 was measured at 128 MPa for the industrially manufactured AA5056_IM and 111 MPa for the AA5056_AM. In contrast, impact toughness tests showed that AA5056_AM KCVfull was 190 kJ/m2, half that of AA5056_IM KCVfull, which was 395 kJ/m2. [ABSTRACT FROM AUTHOR]

The Hugoniot elastic limit and spall strength were measured for a heat-resistant metal-matrix composite Inconel 625–5%NiTi–TiB2 alloy additive manufactured (AM) by direct laser deposition. The strength characteristics of the alloy were obtained from the analysis of the complete wave profiles recorded with a VISAR laser Doppler velocimeter during shock-wave loading of the samples. The samples were loaded using a PP50 pneumatic gun or ad hoc explosive devices along and across the material deposition direction in order to determine the strength anisotropy of the AM alloy under study. The maximum shock compression pressure was ~7 GPa, and the strain rate under tension before spalling varied in the range of 105–106 s–1. Kinetic dependencies of elastic/plastic transition and critical fracture stresses vs. loading conditions were plotted. It was shown that the Hugoniot elastic limit of the alloy under study decreases as the shock wave travels into the sample, while the spall strength increases as the material's strain rate increases at the moment of spall fracture. A comparison of the strength characteristics of the Inconel 625–NiTi–TiB2 composite alloy with the original Inconel 625 alloy has shown that an addition of 5% of powder based on NiTi-TiB2 leads to a decrease in its elastic limit and critical fracture stresses upon spalling by more than 10%. The alloy under study demonstrates anisotropy of strength properties relative to the material deposition direction. [ABSTRACT FROM AUTHOR]