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Structural transformations of nanocrystals in the LaPO4-YPO4-(H2O) oxide system were investigated under hydrothermal conditions at 230°C, depending on isothermal holding times (2 hours, 7 days and 28 days). It was shown that before hydrothermal processing, phases crystallize in the system with rhabdophane structures La1-xYxPO4 · nH2O (0 ≤ x ≤ 0.80) and xenotime YPO4. It has been determined that increasing the duration of isothermal treatment under hydrothermal conditions leads to the transformation of the rhabdophane phase into phases with monazite and equilibrium xenotime structures, with an intermediate crystallization of the metastable monazite phase. It is noted that only after 28 days of hydrothermal treatment at 230°C, the system approaches the equilibrium composition of the phases with monazite structures La0.97Y0.03 PO4 (with crystal sizes of 18-50 nm) and xenotime YPO4 (with crystal sizes of 45-90 nm). In a single-phase sample with a monazite structure La0.75Y0.25 PO4, the average crystal size remains unchanged at around 20 nm after 2 hours, 7 days and 28 days of hydrothermal treatment at 230°C.

To understand and further improve the corrosion resistance of a medium electroless phosphorus nickel coating (9 wt% P) under high-temperature and corrosive conditions, the microstructural evolution of the coating after various treatments, including thermal and mechanical methods (such as Hammer Peening), was extensively studied. Complementary analytical techniques, including SEM, EDS, in situ and ex situ XRD, and micro-indentation, were employed for detailed analysis. The transformation of the deposit from its amorphous state to a distinct structure comprising Ni, Ni 3 P, and NiO due to thermal treatment (ranging from 20 to 800 °C) was examined. The evolution of microstructure with temperature and annealing duration was discussed, correlating with alterations in mechanical properties, particularly micro-hardness. At temperatures exceeding 310 °C, a phase transition occurred, characterized by co-precipitation of Ni and Ni 3 P, leading to a significant change in the coating's mechanical behavior. With further temperature elevation, nickel diffused toward the surface, initiating NiO formation at 500 °C. The coating's oxidation behavior during isothermal treatment at varied temperatures (up to 800 °C) was also explored. This investigation was supported by thermodynamic calculations. Additionally, simplified kinetic simulations with the Dictra module from Thermo-Calc were proven to be able to reproduce the oxidation behavior. Hammer peening treatment enhanced the coating's hardness in its as-deposited state by introducing residual stresses that affected the precipitation kinetics during subsequent heat treatment. However, this hardening effect was no longer evident after the thermal treatment.

Traditional superhydrophobic cotton fabrics (CF) demonstrate various advantages such as self-cleaning, water repelling and efficient oil/water separation capacity but limited practical applications due to their poor mechanical robustness and environmental durability. In this work, robust and durable superhydrophobic polydivinylbenzene (PDVB) coated CF (PDVB@CF) are fabricated via a simple one-step, fluorine-free, and inorganic nanoparticle-free solvothermal method. The PDVB@CF displays excellent chemical resistance without losing superhydrophobicity after immersing in various organic solvents, strong acid and alkali solutions for a long time. The PDVB@CF shows excellent mechanical robustness to resist sandpaper abrasion and ultrasonication treatment. Furthermore, the PDVB@CF exhibits outstanding high and low temperature resistances since the contact angle of either acidic or alkali droplets is greater than 150° after isothermal treatment at 200 °C or immersion in liquid nitrogen for 3 h. The PDVB@CF is very efficient in separating water mixtures with various oily compounds with separation efficiency of higher than 98% and flux up to 56 k L m −2  h −1 depending on characteristics of the oils. In addition, the PDVB@CF shows excellent recyclability with superhydrophobicity and separation efficiency that remained after 10 separation cycles. The PDVB@CF with excellent robustness and durability exhibits potential utility in oil/water separation even under some harsh conditions.

Low-carbon steel has been popularly applied in numerous applications because of its unique features, such as good plasticity, high strength, great hardness, and excellent toughness. Additionally, the semi-solid thixotropic forging forming method has been widely used in light alloys, due to its advantages of low forming force and high forming quality, whereas its application in ferrous materials is still limited. In this study, the semi-solid thixotropic forging forming process is proposed for producing the low-carbon steel claw pole, with the main stages being radial forging deformation, isothermal treatment, and forging forming. The effect of the area reduction rate on the effective strain from the cross sections of the radial-forged metal bar was studied using numerical simulations. The effect of the isothermal holding process on the microstructures of radial-forged billets was investigated, to obtain the ideal semi-solid microstructures. The microstructure and mechanical properties of low-carbon steel claw poles from the thixotropic forging experiment are presented and discussed. It was found that when the area reduction rate was 67%, the effective strain at the edge of the metal bar exceeded 5.0, while the effective strain at the center was above 1.2, indicating an excellent quality of forging for the bar. The optimization of the process parameters for preparing low-carbon steel semi-solid billets with fine and globular microstructures was achieved with an area reduction rate of 67%, an isothermal temperature of 1500 °C, and a duration time of 15 min. Moreover, the low-carbon steel claw pole fabricated with the optimized operating parameters was found fully filled, with a sharp profile and a flat surface, where the yield strength and tensile strength increased by 88.5% and 79.8%, respectively, compared to the starting materials.

For modern advanced high-strength steels, metastable retained austenite (RA) is introduced into a multiphase microstructure to achieve better strength–ductility balance through interphase deformation accommodation and the transformation-induced plasticity effect. Examples include the quenching and partitioning (QP) process and the bainite isothermal process, where carbon enrichment in austenite is achieved by implementing isothermal around the martensite start temperature, thus improving the mechanical stability of the RA. In this study, the dissimilation of the initial microstructure of high-Si alloy before isothermal treatment was realized by adjusting the quenching process over an extensive range. The effects of the partitioning process and initial isothermal microstructure on the mechanical behavior of Fe–0.28C–2.52Si–2.62Mn–0.05Nb steel were investigated. The two-step QP steel exhibited a better strength–ductility balance than the one-step steel. The tensile strength of the two-step sample reached 1700 MPa and had a product of tensile strength and total elongation of 26.2 GPa %. The results showed that the initial formation of athermal martensite accelerated the subsequent bainite transformation kinetics during partitioning. During isothermal holding, the formation of martensite or (and) bainite contributed to the stability of RA via carbon redistribution. Specimens with stable RA exhibited a lower initial work-hardening rate during deformation. A relatively higher volume fraction of RA leads to a continuous work-hardening behavior, thereby significantly improving the total elongation.

Lanthanides were tested (Ce3+, Er3+, and Yb3+) as catalysts to produce lactic acid (LA) from the monosaccharides present in corn stover (glucose, xylose, and arabinose) resulting in ytterbium being the most active. A MW-heated system led to similar LA yield as a conventionally heated pressurized system. The maximum value of LA yield was 40% at 240 °C after 20 min of isothermal treatment regardless the starting monosaccharides, which allowed to propose a similar LA production route based on the products profile determined along time for the three monosaccharides. Temperature and time determined the product profile, observing furfural degradation at severity factors higher than 3.5, while values higher than 5.5 were needed to observe LA degradation. By increasing temperature, catalyst solubility decreased, increasing its presence in the solid residue after treatment. Xylan conversion to LA was similar as for xylose, but lower yield was obtained from microcrystalline cellulose. Corn stover presented more amorphous regions leading to higher hydrolysis yields of its cellulose fraction.

The formation of titanium carbide (TiC) may result in slag thickening, slag foaming and difficulty in separation between hot metal and slag etc during the blast furnace smelting process with Vanadic Titanomagnetite. Therefore, it is very important to understand and manage the formation of titanium carbide. The formation mechanism of titanium carbide during the reduction process of blast furnace slag - bearing titanium was studied with theoretical calculations and experiments. In the experiment, blast furnace slag - bearing titanium was subjected to 6 hours’ isothermal treatment at temperature range of I300°C-I550°Cin graphite crucible with Ar flow rate of 2L/min (1 atm). The reduced slag was characterized by mineralogical microscope and SEM-EDS detection methods. As a result, the formation of titanium carbide started at a temperature higher than I400°C.

Alloy 4822 (Ti-48Al-2Cr-2Nb at. pct) cast material was given a controlled heat treatment cycle to generate a casting nearly lamellar (CNL) microstructure that enhances the temperature capability over its current engineering casting duplex (CDP) microstructure form. The cycle consisted of three steps: a short α field annealing, an α + γ field annealing, and then aging at a low temperature, with each step being followed by controlled cooling. The resulted microstructure is shown to be a mixture of non-uniformly distributed ~ 250 μm size lamellar colonies containing ~ 0.15 µm spaced laths. Standard tensile testing at 700 °C shows a yield stress of 344 MPa that is ~ 55 MPa greater than that of the current engineering CDP form. The sequential microstructure evolution processes following the three-step thermal cycle are assessed and explained in terms of phase transformations taking place across and below the α transus upon isothermal treatment and subsequent cooling. The resulted increases in high-temperature strengthening are explained by the colony and γ grain size distributions. The strengthening mechanism along with the significance is discussed.

We studied the formation of optimal hysteresis properties and characteristics in materials for nonlinear magnetic systems of hysteretic electromechanical energy converters and directly in these systems. The influence of isothermal treatment on the properties of the specified materials and systems is investigated; the residual induction, coercive force and maximum energy product are studied.

Quenching and partitioning (Q&P) treatments were applied to 0.25C steel to produce the microstructures that exhibit an improved balance of mechanical properties. The simultaneous bainitic transformation and carbon enrichment of retained austenite (RA) during the partitioning stage at 350 °C result in the coexistence of RA islands with irregular shapes embedded in bainitic ferrite and film-like RA in the martensitic matrix. The decomposition of coarse RA islands and the tempering of primary martensite during partitioning is accompanied by a decrease in the dislocation density and the precipitation/growth of η-carbide in the lath interiors of primary martensite. The best combinations of a yield strength above 1200 MPa and an impact toughness of about 100 J were obtained in the steel samples quenched to 210–230 °C and subjected to partitioning at 350 °C for 100–600 s. A detailed analysis of the microstructures and the mechanical properties of the steel subjected to Q&P, water quenching, and isothermal treatment revealed that the ideal strength–toughness combinations could be attributed to the mixture of the tempered lath martensite with finely dispersed and stabilized RA and the particles of η-carbide located in the lath interiors.