Numerical simulation was carried out on the vacuum arc remelting （VAR） process of CrNiMoAlTi series precipitation-hardening stainless steel using the Meltflow-VAR software. The effects of different melting rates， helium pressures， and feeding processes on the molten pool morphology and the formation tendency of ingot black spot defects during the VAR process were calculated， and statistical analysis of inclusions was also performed. The results show that with the increase of melting rate， the molten pool morphology transforms from a shallow and flat "U" shape to a deeper "V" shape， and the mushy zone also expands with the rising melting rate. When the melting rate is 5.0 kg/min， the formation tendency of black spots in the core region is minimized， which is conducive to the floating of inclusions. The heat transfer efficiency of the helium layer increases with the increase of helium pressure. At a helium pressure of 300 Pa， the depth-diameter ratio of the molten pool reaches the minimum value， which is beneficial to heat transfer， reduces the risk of element segregation， and significantly improves the formation tendency of ingot black spots. The optimal setting of melting rate reduction rate in the feeding stage is 0.03 kg/min， which can increase the cooling rate of the feeding end and improve the formation tendency of ingot black spots. After the VAR process， the total number of TiN inclusions in the center of the ingot is less than that in the edge region of the ingot， and the total number of inclusions in the head of the ingot is more than that in the tail of the ingot. No inclusions larger than 25 μm are found in any part of the ingot， and the rating of various inclusions is ≤ 0.5.

In order to systematically study the effect of quenching and tempering temperature on the mechanical properties of 21Cr12MoV martensitic heat-resistant stainless steel， specimens of the steel were prepared using various heat treatment processes. Subsequently， tensile tests， hardness tests， impact tests， as well as metallographic and fracture surface analyses were conducted. The results show that the tensile and impact properties of the material are optimal when the quenching temperature is 1 050 ℃. The tensile strength is 973 MPa， and the impact energy is 37.6 J. As the tempering temperature increases， the strength and hardness of the material gradually decrease， while the impact toughness gradually increases. To achieve the optimal strength - toughness balance and the best overall performance of the product， the recommended heat treatment process consists of a quenching temperature of 1 050 ℃ and a tempering temperature of 680 ℃.

FeCoNiAl0.2Si0.3 high-entropy alloy (HEA) powders with different wet milling durations (2 h, 4 h, 6 h, 8 h, 10 h, 12 h) were synthesized through a mechanical alloying process that combined dry and wet milling. As the wet milling duration increased, the average particle size of the powder gradually decreased and the particle morphology shifted from flaky to irregular shapes. The samples with irregular particles, although they exhibit a reduced ability to attenuate incident electromagnetic waves compared to samples with flake particles, due to their superior impedance matching, demonstrate excellent overall microwave absorption performance. The sample with wet milling duration of 10 h (S10) demonstrated a minimum reflection loss (RLmin) of -60.22 dB at 7.20 GHz and achieved the effective absorption bandwidth (EAB) of 6.48 GHz (10.08 GHz-16.56 GHz) at 1.59 mm. This research offers valuable insights for synthesizing high-performance HEA microwave absorbing materials through mechanical alloying technology.

Titanium/medium carbon steel (Ti/Steel) marine components face severe reliability challenges due to the brittle intermetallic compound generation. Conventional interlayers are limited in preventing the precipitation of compounds or mitigating their adverse effects on the processing window. To address this, a heterogeneous Ni-Cr interlayer was designed to spatially regulate atomic diffusion. By controlling bonding temperature (880-970 degrees C), a diffusion-induced periodic alternating microstructure was achieved, where Ti diffusion was promoted at Ni units forming Ti-Ni phases while suppressed at Cr units. At temperatures <= 910 degrees C, solid-phase diffusion formed thin Ti-Ni reaction zones with beta-Ti/Ti-2(Fe-0.Ni-5(0).(5)) phases, yielding peak shear strength (150.7 MPa). Higher temperatures (>910 degrees C) triggered eutectic liquefaction, thickening reaction zones but promoting brittle TiC formation that reduced strength to 90.1 MPa. Crucially, ductility rebounded from 8.6 % to 12.3 % due to shear stress redistribution enabled by the periodic alternating microstructure. This work establishes a universal principle that detrimental intermetallic compounds can be transformed into structural assets when optimized through interlayer design and diffusion control, providing a paradigm for toughening dissimilar joints.

During the high-temperature preparation of stainless steel cladding plate, carbon atoms from carbon steel diffused into stainless steel. When temperatures were within 450–850 °C, carbides precipitated at grain boundaries, which initiated intergranular sensitization and thereby reduced the corrosion resistance of stainless steel. This study designed NiP and NiCuP interlayer alloys to effectively block carbon diffusion in stainless steel cladding plates. The effect of adding interlayers on the microstructure of stainless steel cladding plate was studied by using optical microscopy and scanning electron microscopy. Electrochemical tests were subsequently conducted to evaluate the impact of interlayer incorporation on the corrosion resistance of stainless steel cladding. The results demonstrated that 304/45 specimens exhibited severe carbon diffusion, resulting in the poorest corrosion resistance. The addition of interlayers improved the corrosion resistance of stainless steel cladding to varying degrees. Among these, the 304/NiCuP/45 specimen showed the best performance. It had an intergranular corrosion susceptibility of only 0.25% and pitting potential as high as 0.336 V, which indicated its superior corrosion resistance. The passive film of stainless steel cladding exhibited n-type semiconductor characteristics. And 304/NiCuP/45 specimen demonstrated the lowest carrier density of 3.02 × 1018 cm−3, which indicated the formation of the densest passive film.

For searching alternative strategies to improve reliability of titanium and steel dissimilar bimetallic joints manufactured by directed energy deposition with laser beam (DED-LB), pure titanium was considered as cladding deposited on carbon steel substrate with Ni-based alloy interlayers in this work. Effect of different interlayer modification methods on the microstructure evolution and mechanical properties of joints was analyzed systematically. The distribution of intermetallic compounds (IMCs) such as β-Ti, Ti2Ni, TiNiFe0.2, Ti2Ni3Si and TiB2 in joints was revealed. The results showed that original deposition cracks caused by residual stress during processing could be alleviated by substrate preheating treatment while suppressed by the modified interlayer with Cr completely. Notably, additional Cr could reduce reaction activity between Ti and Ni atoms by raising laser molten pool liquidus, leading to fewer IMCs in joints. As a result, both bonding strength and toughness of joints were remarkably improved. The findings emphasize more significance of optimizing Ni-based interlayer composition with Cr than preheating method to improve the mechanical performance of DED-LB joints.

During the heat treatment of stainless steel (SS)/carbon steel (CS) bimetal composites, the carbon in the CS diffuses into the SS, and carbides precipitate on the grain boundary and in the grains, affecting the microstructure and properties of the composite steel. In order to change the precipitation and distribution of the carbides seen on hot-rolled 304/Q235 after cold drawing (HR), the microstructure and properties of composite round steel were investigated by optical microscopy, SEM/EDS, and hardness, tensile, fatigue, and electrochemical tests while changing the temperature of the full annealing and aging treatments. The results showed that dispersed chromium carbide particles precipitated at the grain boundaries, and intragranular and slip lines promoted simultaneous dispersion strengthening and fine-grain strengthening and greatly improved the hardness, yield strength, tensile strength, and fatigue strength of the composite round steel. However, the increase in chromium carbide particles leads to the formation of stress concentration points and accelerates the creation of fatigue cracks, resulting in a decrease in the fatigue strength of the steel. Simultaneously, the corrosion resistance of the composite round steel samples was reduced due to the precipitation of a large amount of chromium carbide.

The hot-rolled 304/Q235 (HR) bimetal composite bolst have been manufactured by hot rolling compound, drawing and thread rolling. By changing the sequence of heat treatment and thread rolling process to produce first thread rolling and then heat treatment 304/Q235 (TRH) bolts, first heat treatment and then thread rolling 304/Q235 (HTR) bolts. Subsequently, their microstructure, fatigue, and corrosion resistance were studied and compared with those of Q235 carbon steel (CS) and 304 stainless steel (SS) bolts. The results indicate that the fatigue performance of TRH bolts is the poorest, with a fatigue life of 11,838 cycles under a bending stress of 300 MPa. The TRH bolts' SS cladding has the most severe intergranular sensitization and the poorest corrosion resistance. Because of combined effects of dispersion strengthening and cold deformation hardening, HTR bolts have the highest cladding hardness (601 HV), and the fatigue performance of HTR bolts is the best, with a fatigue limit of 270 MPa. Under a bending stress of 300 MPa, the fatigue life is 434,717 cycles, which is far superior to that of Q235 pure material bolt. At the same time, HTR bolts have good corrosion resistance and possesse excellent comprehensive performance and significant practical importance.

The increasing demand for energy, coupled with the continuing deterioration of the environment, has heightened people's desire for renewable energy storage technologies, such as rechargeable zinc‐air batteries (ZABs). However, the race for the developing ZABs usually focuses on the search for new materials, with less emphasis on electrode engineering and recycling. Herein, for the first time, a simple, scalable, and inexpensive electrode engineering and recycling strategy for ZABs is proposed based on the magnetic binder engineering of the cobalt‐implanted electrocatalysts. By manipulating the electrode with magnets, the ZAB can cycle for 1200 h (7200 cycles), and its anti‐pulverization behavior is revealed through in situ observation of a visual cell with an air electrode in the charged state. Moreover, the cobalt‐implanted electrocatalysts can be recycled from the spent ZABs using a magnetic force‐separation method. Additionally, the ZAB with the recycled electrocatalyst exhibits considerably prolonged cycling stability for over 500 h (ΔE = 0.86 V). This study not only enables the design of magnetic force‐engineered electrodes with improved battery performance but also provides sustainable solutions for recycling electrocatalysts for many possible applications beyond ZABs.

This paper utilized a hot-rolling process to produce composite rods and subsequently manufactured 304/45 composite bolts through the process of drawing and thread rolling. The study focused on examining the microstructure, fatigue performance, and corrosion resistance of these composite bolts. Additionally, the impacts of quenching and tempering on the fatigue performance of the composite bolts were explored and compared to the performance of 304 stainless steel (SS) bolts and Grade 6.8 35K carbon steel (CS) bolts. The results indicate that the SS cladding of the cold-worked 304/45 composite (304/45-CW) bolts was primarily strengthened by the cold deformation mechanism, which resulted in high microhardness, averaging 474 HV. At a maximum surface bending stress of 300 MPa, the fatigue cycles of the 304/45-CW reached 342,600 cycles at a 63.2% failure probability, which was significantly higher than that of commercial 35K CS bolts. The S-N fatigue curves showed that the fatigue strength of the 304/45-CW bolts was approximately 240 MPa, but the fatigue strength of the quenched and tempered 304/45 composite (304/45-QT) bolts decreased significantly to 85 MPa, due to the loss of the cold deformation strengthening effect. The corrosion resistance of the SS cladding of the 304/45-CW bolts was impressive and remained largely unaffected by carbon element diffusion.

With the application of stainless steel clad plate (SSCP)-enlarging in the marine engineering field, awareness of the consequences of heat treatment on ameliorating microstructure and mechanical properties in stainless steel (SS)/carbon steel (CS) joints is being raised. However, carbide diffusion from a CS substrate to SS cladding may damage the corrosion resistance during inappropriate heating. In this paper, the corrosion behavior of a hot rolling-produced stainless steel clad plate (SSCP) after quenching and tempering (Q-T) treatment, especially crevice corrosion, was studied by electrochemical and morphological methods, such as cyclic potentiodynamic polarization (CPP), confocal laser scanning microscope (CLSM) and scanning electron microscopy (SEM). Q-T treatment led to more significance in carbon atoms diffusion and carbide precipitation, which made the passive film of the SS cladding surface on the SSCP unstable. Subsequently, a device for measuring the crevice corrosion performance of SS cladding was designed; the Q-T-treated cladding showed lower re-passivation potential (−585 mV) during CPP when compared to as-rolled (−522 mV), with the maximum corrosion depth ranging from 70.1 μm to 150.2 μm. In addition, the processing of crevice corrosion on SS cladding could be divided into three parts, including the initiation, propagation and development stages, which were driven by the interactions between corrosive media and carbides. The generation and growth mechanism of corrosive pits in crevices were revealed.

Heat treatments are necessary sometimes in order to improve comprehensive properties of stainless steel cladding plate (SSCP). However, carbon atoms in carbon steel diffuse into stainless cladding during the heat treatment process, thus decreasing its corrosion resistance. In this paper, optical microscopy, scanning electron microscopy, and microhardness and shear testing were employed to characterize the microstructure and mechanical properties of the bonding interface in SSCP. Then, the corrosion resistance of the stainless steel cladding surface was evaluated by electrochemical tests. The results showed that the diffusion of carbon atoms played an important role in enhancing the bonding strength of SSCP, but might lead to intergranular sensitization of the cladding surface because of chromium carbide precipitation. Notably, this precipitation could be induced by quenching and tempering treatment, and hindered by solution treatment. Hence, the cladding surface on SSCP after single solution treatment possessed the superior corrosion resistance, and SSCP with continuous solution and tempering treatment exhibited the highest bonding strength.

Multi-interlayer composed of Ni and microcracked Cr (MC-Cr), formed by electrochemical deposition, was applied to induce the formation of wavy microstructure enhancing bonding strength of titanium to carbon steel brazed joints with BAg45CuZn filler. Effect of microcrack density in Cr layer on microstructure evolution and mechanical properties of joints has been studied. Phase identification and formation mechanism of joints were analyzed systematically. Introducing multilayer with microcracks avoided the formation of brittle Ti-C and Fe-Ti phases near carbon steel substrate. During bonding, the diffusion of Ti atoms was hindered by compact Cr while promoted by Ni at microcracks. The inhomogeneous diffusion of Ti atoms led to the generation of a wavy microstructure unit that is crater-shaped structure, accompanied by the enrichment of beta-CuZn, Fe0.2Ni4.8Ti5 and Cu2TiZn phases. The fracture results showed that these structures improved the shear strength of joints up to 242 MPa by altering the direction of crack propagation.

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/ourbusiness/policies/article-withdrawal

Although direct glucose fuel cell (DGFC) is widely regarded as one of the most promising energy systems, the low catalytic activity and inferior instability of most anode catalysts during electro-oxidation of glucose has greatly hampered its potential applications. In this work, an efficient and durable anode catalyst of nanoporous bismuth (Bi) for the alkaline electro-oxidation of glucose was proposed just by a simple de-alloying method. The microstructure and catalytic performance of nanoporous bismuth could be finely tuning through actively controlling the composition of precursor Mg-Bi alloy. A three-dimension structure was formed after de-alloying Mg-Bi precursor, giving rise to an increased specific surface area and correspondingly resulting in an enhanced electro-catalytic performance. It has intimated that the optimal nanoporous Bi catalyst with an open, bi-continuous interpenetrating pore-to-ligament structure was constructed based on Mg65Bi35 alloy etching and exhibited an enhanced current density (as high as 8.04 mA/cm(2)) during alkaline electro-oxidation of glucose, together with the lowest poisoning rate of 5.6 x 10(-3)%. The remarkable electrochemical performance of the nanoporous Bi catalyst, coupling with facile dealloying strategy may facilitate design and development of renewable energy device. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Herein, the effects of Fe substitution for Ni on glass-forming ability (GFA), mechanical properties and corrosion resistance of Zr56Cu24Al9Ni7-xTi4Fex (x = 0, 1, 3, 5, and 7 at.%) bulk metallic glass (BMGs) were investigated. Trace addition of Fe to 3 at.% slightly affects the GFA of alloys, but Fe over-dosage results in an intense susceptibility to crystallization and failure to form metallic glasses. Furthermore, the compressive strength and plasticity of Zr56Cu24Al9Ni4Ti4Fe3 alloy are significantly enhanced to 1709 MPa and 5.55%, respectively, compared to 1677 MPa and 1.22% for pristine alloy. Meanwhile, the corrosion resistance is greatly improved by Fe addition to 3 at.% then deteriorated with its excess addition. The Zr56Cu24Al9Ni4Ti4Fe3 alloy exhibits the widest passivization zone and the largest Rct, indicating an enhanced corrosion performance. Overall, the synergistic effect of Fe substitution on mechanical and corrosion performance opens a new horizon for design of toxic-free Zr-based BMGs for potential application.

Ni-free Zr-Ti-Cu-Fe-Al bulk metallic glass (BMG) is regarded as a prospective candidate for practical applications. However, a high Ti content in the BMG causes a sharp deterioration of mechanical performance. Herein, the effects of isothermal annealing on the structure, mechanical performance, and corrosion resistance of the Zr59Ti6Cu17.5Fe10Al7.5 BMG are investigated. The alloy after a short-time annealing at 573 K shows admirable compressive strength and plasticity of 1910 MPa and 12.1%, respectively, which are much higher than 1733 MPa and 4.3% of the pristine BMG. This enhancement was ascribed to precipitation of ultrafine Al3Zr2 nanograins from the BMG matrix. However, the prolonged annealing induces propagation of nanocrystals and decreases free volume in the alloys, leading to the deterioration of mechanical performance. The electrochemical study demonstrates that the BMG maintains good corrosion resistance after the annealing. This work offers an avenue for designing high-performance Ni-free BMG-based alloys.

The effect of carbon content on the precipitation and distribution of intermetallic compounds in titanium to decarbonized carbon steel brazed joint was studied. In this work, decarbonization treatment was employed to change the carbon content in the low carbon steel surface and thus influence the diffusion behavior of Ti and Fe elements in the joint. The microstructure, fracture surface and bonding strength of joints were detected by SEM/ EDS, XRD and shear strength test. As a result, rich -carbon state in the steel surface profited the bonding of dissimilar joint to some extent during brazing process. TiC generated near carbon steel side can improve the bonding strength of joints by hindering the precipitation of FeTi and Fe2Ti. Precipitation and distribution of TiC, FeTi and Fe2Ti intermetallic compounds in joints were investigated.

Zr-based bulk metallic glasses (BMG) Zr65+xCu17.5Fe10-xAl7.5 (x = 0, 2.5, 5, 7.5) with high zirconium content were prepared by an injection copper-mold casting method. The influence of Zr partially substituted Fe and isothermal annealing on the microstructure and mechanical properties of the Zr65+xCu17.5Fe10-xAl7.5 BMGs has been systematically studied. The as-prepared BMG with a Zr content of 70 at.% achieves superior glass forming ability with a large supercooled liquid region width of 82 K and compressive performance. An optimized isothermal annealing (0.5 h) below the glass transition temperature of the as-cast Zr70Cu17.5Fe5Al7.5 BMG contributes significant enhancement in compressive fracture strength and plasticity, from 1845 MPa and 7.4% (as-cast) to 2096 MPa and 12.7% (annealed), respectively. The result of the present study provides a new strategy for designing high-performance BMG-based alloys.

The introduction of heterojunctions is an effective way to improve catalytic activity in photocatalytic composites. Herein, a series of CdSe quantum dot-modified BiOCl heterojunction composites were successfully prepared by a green in-situ deposition protocol. Photocatalytic ability of CdSe/BiOCl composite can be simply tailored by adjusting CdSe amount. The obtained CdSe/BiOCl composites showed superior photodegradation capability and excellent stability. The optimum BiOCl composite with 1.0% CdSe modification exhibited a 1.5 times higher degradation rate than pure BiOCl nanosheets, and photodegradation efficiency maintains still high after four cycles. Physical characterization confirms the formation of heterostructure, while electrochemical impedance spectroscopy and photoluminescence spectrum demonstrate composite with higher separation efficiency of photo-generated electron-hole pairs. At last, the heterojunction of Z-Scheme satisfies the photocatalytic mechanism of CdSe/BiOCl, and the holes (h(+)) with superoxide radicals (.O-2(-)) are the main active factors in photodegradation process based on the experiment of scavengers.