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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.

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 presents the results of measurements of the spall strength and elastic-plastic proper-ties, under dynamic and static loads, of the high-strength heat-resistant nickel-chromium alloy Inconel 625, obtained by the direct laser deposition method. The structural parameters of the obtained samples and the mechanical properties during static tests were studied. According to our information, anisotropy in the structural parameters operates primarily at the level of plastic deformation of alloys. Shock compression of the additive alloy Inconel 625 samples in the range of 6–18 GPa was carried out using a light-gas gun, both along and perpendicular to the direction of the deposition. The strength characteristics were determined from the analysis of the shock wave profiles, which were recorded using the VISAR laser velocimeter during the loading of samples. It was found that the value of the spall strength of additive samples does not depend on the direction of deposition, and the Hugoniot elastic limit of samples loaded perpendicular to the deposition direction is about ~10% higher. With an increase in the maximum compression stress, the material’s spall strength increases slightly, but for both types of samples, a slight decrease in the Hugoniot elastic limit was observed as the compression stresses increase. On the basis of the measured wave profiles, shock Hugoniots of the samples of the alloy Inconel 625, loaded both along and perpendicular to the direction of deposition, are constructed in this pressure range.

In this work, the critical fracture stresses during spalling of high-strength steel 09CrNi2MoCu samples obtained by direct laser deposition (DLD) were measured under shock compression of up to ~5.5 GPa. The microstructure and mechanical properties of DLD steel samples in the initial state and after heat treatment were studied and compared to traditional hot rolled one. The microstructural features of steel before and after heat treatment were revealed. The heat treatment modes of the deposit specimens on their strength properties under both static and dynamic loads have been investigated. The spall strength of the deposited specimens is somewhat lower than the strength of steel specimens after hot rolling regardless of their heat treatment. The minimum elastic limit of elasticity is exhibited by the deposit specimens. After heat treatment of the deposit samples, the elastic limit increases and approximately doubles. Subsequent heat treatment in the form of hardening and tempering allows obtaining strength properties under Hugoniot loads in traditional hot-rolled products.