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The paper presents the results of the analysis of the resistance to hydrogen and high-temperature salt corrosion of the developed alloy of the CM88Y type for the turbine blades of gas turbine engines for marine and power purposes in comparison with the industrial heat-resistant corrosion-resistant alloy CM88Y and the alloy for the protective coating of the SDP3-A blades. SDP3-A alloy was chosen as a reference sample, which has high hydrogen and corrosion resistance. The new heat-resistant alloy additionally contains such refractory metals as rhenium and tantalum, which are added to the composition of the alloy in order to increase operational characteristics while maintaining phase-structural stability. These are properties such as long-term and fatigue strength, characteristics of plasticity and strength at room and elevated temperatures. Therefore, the purpose of these studies was to determine the resistance to high-temperature salt corrosion of the developed alloy in comparison with the industrial heat-resistant nickel alloy and to evaluate the influence of alloying, hydrogen embrittlement of CM88Y and ZhS3DK alloys with different contents of chromium, boron, zirconium, hafnium, and yttrium were compared. The corrosion resistance of the materials was evaluated after crucible tests in a salt solution at a temperature of 900 °C for 30 h, according to the standard method. The corrosion resistances of alloys were determined by the mass loss, corrosion rate, and data from metallographic studies.

The NiAl–Cr–Co–X alloys were produced by centrifugal self-propagating high-temperature synthesis (SHS) casting. The effects of dopants X = La, Mo, Zr, Ta, and Re on combustion, as well as the phase composition, structure, and properties of the resulting cast alloys, have been studied. The greatest improvement in overall properties was achieved when the alloys were co-doped with 15% Mo and 1.5% Re. By forming a ductile matrix, molybdenum enhanced strength characteristics up to the values σucs = 1604 ± 80 MPa, σys = 1520 ± 80 MPa, and εpd = 0.79%, while annealing at T = 1250 ℃ and t = 180 min improved strength characteristics to the following level: σucs = 1800 ± 80 MPa, σys = 1670 ± 80 MPa, and εpd = 1.58%. Rhenium modified the structure of the alloy and further improved its properties. The mechanical properties of the NiAl, ZrNi5, Ni0.92Ta0.08, (Al,Ta)Ni3, and Al(Re,Ni)3 phases were determined by nanoindentation. The three-level hierarchical structure of the NiAl–Cr–Co+15%Mo alloy was identified. The optimal plasma treatment regime was identified, and narrow-fraction powders (fraction 8–27 µm) characterized by 95% degree of spheroidization and the content of nanosized fraction <5% were obtained.

The capability for synergistic advancements in both making and shaping afforded by additive manufacturing (AM) enables the flexible production of high-performance components. Boosted by the growing demand for heat-resistant aluminum alloys in the moderate-temperature weight-critical applications, AM of heat-resistant aluminum alloys constitutes a burgeoning field. Although numerous advances have emerged in recent years, there remains a gap in the review literature elucidating the newly-developed alloy systems and critically evaluating the efficacy. This state-of-the-art review presents a detailed overview of recent achievements on the heat-resistant aluminum alloy development. It begins with the introduction of various AM technologies and the pros and cons of each technique are evaluated. The enhancement mechanisms associated with printability and high-temperature properties of AM aluminum alloys are then delineated. Thereafter, the various additively manufactured aluminum alloy systems are discussed with regard to the microstructure, heat resistance and high-temperature performance. An emphasis is put on the powder bed fusion-laser beam (PBF-LB) as it has garnered significant attention for heat-resistant aluminum alloys and the vast majority of the current studies are based on this technique. Finally, perspectives are outlined to provide guidance for future research. AM technologies for metals are evaluated with an emphasis on PBF-LB technique. Eutectic systems and inoculation treatment enable crack suppression of AM Al alloys. The high-temperature strengthening mechanisms of AM Al alloys are discussed. Microstructures and heat resistance of various AM Al alloy systems are evaluated. Perspectives on AM heat-resistant Al alloys are outlined.

Alloys based on NiAl-Cr-Co (base) with complex dopants (base+2.5Mo-0.5Re-0.5Ta, base+2.5Mo-1.5Re-1.5Ta, base+2.5Mo-1.5Ta-1.5La-0.5Ru, base+2.5Mo-1.5Re-1.5Ta-0.2Ti, base+2.5Mo-1.5Re-1.5Ta-0.2Zr) were fabricated by centrifugal SHS metallurgy. The phase and impurity compositions, structure, mechanical properties, and the mechanism of high-temperature oxidation at T = 1150 °C were studied; the kinetic oxidation curves, fitting equations and parabolic rate constant were plotted. Al2O3 and Co2CrO4 were the major phases of the oxidized layer. Three layers were formed: I—the continuous Al2O3 layer with Co2CrO4 inclusions; II—the transitional MeN-Me layer with AlN inclusions; and III—the metal layer with AlN inclusions. The positive effect of thermo-vacuum treatment (TVT) on high-temperature oxidation resistance of the alloy was observed. The total weight gain by the samples after oxidative annealing decreased threefold (from 120 ± 5 g/m2 to 40 ± 5 g/m2). The phases containing Ru and Ti microdopants, which reduced the content of dissolved nitrogen and oxygen in the intermetallic phase to the values ∑O, N = 0.0145 wt.% for the base+2.5Mo-1.5Ta-1.5La-0.5Ru alloy and ∑O,N = 0.0223 wt.% for the base+2.5Mo-1.5Re-1.5Ta-0.2Ti alloy, were identified by transmission electron microscopy (TEM). In addition, with the significant high-temperature oxidation resistance, the latter alloy with Ti had the optimal combination of mechanical properties (σucs = 1644 ± 30 MPa; σys = 1518 ± 25 MPa).

Heat-resistant alloys with excellent mechanical properties are widely used in various fields, and further improvement in their properties is essential to meet the requirements in new-generation advanced supercritical boilers, nuclear reactors, superheaters, and other new materials applications. To effectively enhance the comprehensive performance of heat-resistant alloys, second-phase particle strengthening has been widely studied, and in the face of different service environments of advanced heat-resistant steels, the selection of suitable second-phase particles is essential to maximize the performance of these alloys. To this end, three major types of reinforcing phases in heat-resistant alloys such as carbides, rare earth oxides, and intermetallic compounds are summarized. A comparative analysis of the precipitation behavior of the reinforcing phases with different types as well as the risks and means of controlling their use in service, is presented. Key parameters for the application of various types of second-phase particles in heat-resistant alloys are provided to support the design and preparation of new ultrahigh-performance heat-resistant alloys.

The effect of Yb on the microstructure and tensile properties at room temperature and high temperature (350 °C) of as-cast and T6 heat-treated Al-6Cu-0.4Mn alloys was investigated. The results show that Yb can refine the α-Al primary grain and α-Al + Al2Cu eutectic structure. The eutectic structure of the alloy containing 0.3 wt.%Yb has the best refining effect. After the T6 heat treatment, most of the network α-Al + Al2Cu eutectic structure disappeared, and many dispersed (200–400 nm) θ′-Al2Cu phases were precipitated in the matrix. With the addition of Yb, the amount of θ′-Al2Cu phases increases, and the average size decreases from 260 nm in the base alloy to 176 nm in the Yb-containing alloy, which indicates that Yb can promote the precipitation and refinement of the θ′-Al2Cu phase; after adding Yb, the high-temperature ultimate tensile strengths (UTS) of the as-cast and heat-treated alloy significantly increase. Both reached their highest when the Yb additions were 0.3 wt.%, reaching 95.5 MPa and 142.3 MPa, respectively, 13.66% and 17.71% higher than the base alloy. The thermal exposure test at 350 °C shows that Yb can improve the θ′-Al2Cu phase’s coarsening resistance. Analysis shows that the improvement of mechanical properties at room temperature is due to solid solution strengthening and grain refinement of Yb. The reason for improving mechanical properties at high temperatures is that adding Yb promotes the precipitation, refinement, and thermal stability of the θ′-Al2Cu phase.

By recording and analyzing complete wave profiles using the VISAR laser interferometer, measurements of the Hugoniot elastic limit and critical fracture stresses were carried out under the spalling conditions of the heat-resistant Inconel 718 alloy, additively manufactured by direct laser deposition, at shockwave loading up to ~6.5 GPa using a light-gas gun. For comparison, similar experiments were performed with the Inconel 718 alloy made by the traditional method of vacuum induction melting. The process of the delay of an elastic compression wave during its propagation through the sample and the dependence of the spall strength on the strain before fracture in the range 105–106 s−1 were investigated. To identify the anisotropy of the strength properties of the material under study, two series of experiments were carried out on loading additively manufactured samples along and perpendicular to the direction of the deposition. The measurements performed showed that the additively manufactured Inconel 718 alloy demonstrates weak anisotropy of strength properties for both the initial and thermal-treated samples. The thermal treatment leads to a noticeable increase in the Hugoniot elastic limit and the spall strength of the samples at low strain rates. For all types of samples, there is an increase in the spall strength with an increase in the strain rate. The spall strength measured for the cast alloy practically coincides with the strength of the as-received additive alloy and is noticeably lower than the strength of the thermal-treated additive alloy over the entire range of the strain rates. The process of the decay of the elastic precursor in the cast alloy occurs much faster than in the additive one, and the minimum values of the Hugoniot elastic limit are measured for thick samples in the cast alloy.

This paper employed squeeze-casting (SC) technology to develop a novel Al-7Si-1.5Cu-1.2Ni-0.4Mg-0.3Mn-0.15Ti heat-resistant alloy, addressing the issue of low room/high temperature elongation in traditional gravity casting (GC). Initially, the effects of SC and GC processes on the microstructure and properties of the alloy were investigated, followed by an examination of the evolution of the microstructure and properties of the SC samples over thermal exposure time. The results indicate that the SC process significantly improves the alloy’s microstructure. Compared to the GC alloy, the secondary dendrite arm spacing of the as-cast SC alloy is refined from 50.5 μm to 18.5 μm. Meanwhile, the size and roundness of the eutectic Si phase in the T6-treated SC alloy are optimized from 11.7 μm and 0.75 μm to 9.5 μm and 0.85 μm, respectively, and casting defects such as porosity are reduced. Consequently, the ultimate tensile strengths (UTSs) at room temperature and at 250 °C of the SC alloy are 5% and 4.9% higher than that of GC alloy, respectively, and its elongation at both temperatures shows significant improvement. After thermal exposure at 250 °C for 120 h, the morphology of the residual second phase at the grain boundaries in the SC alloy becomes more rounded, but the eutectic Si and nano-precipitates undergo significant coarsening, resulting in a 49% decrease in UTS.

The hot deformation behavior and the microstructure characteristics of alloy 617 and alloy C-HRA-2 were compared and analyzed. The removal of Al and Ti elements has a significant change in the hot deformation of the alloy, and there are two opposite effects on the flow stress before and after recrystallization. The results show that the removal of Al and Ti elements increases the flow stress of the alloy under high temperature or low strain rate deformation conditions. This is mainly due to the increase in the stacking fault energy of the alloy so that the alloy contains a higher twin boundary fraction after dynamic recrystallization (DRX). However, before DRX occurs, that is, at low temperature and high strain rate, the flow stress of this alloy is relatively reduced. This is due to the reduction in Peierls–Nabarro stress, making the alloy more prone to dislocation slip.

The anisotropy of the elastic properties of Inconel 718 alloy produced by 3D printing (selective laser sintering) from powders was studied depending on the direction of 3D printing. The influence of the initial powder mixture and the subsequent heat treatment (post-printing treatment) on the anisotropy of the elastic properties of the alloy was evaluated. It was shown that the proposed treatments can reduce the anisotropy of the elastic properties of the alloy. The results of the theoretical estimation of the elastic and shear moduli, Poisson’s ratio, and their anisotropy in the horizontal and vertical directions of 3D printing are presented, using elastic constants of the single crystal and texture characteristics determined by X-ray diffraction. It is shown that the obtained theoretical values deviate from the corresponding experimental ones by 6–10%. The results of elastic properties and their anisotropy estimating can be used to improve the accuracy of calculating the stress-strain state and optimize the strategy of 3D printing of complex parts made of Inconel 718 alloy.