Search

The investigation aims to explore the relationship between the microstructure and mechanical properties of transient liquid phase‐bonded joints of Inconel 718 (IN718) nickel‐based superalloy, utilizing BNi‐1 and BNi‐2 interlayers with a thickness of 50 μm, produced at 1150 °C for varying durations. Microstructural analysis, facilitated by scanning electron microscopy, and phase analysis, utilizing energy‐dispersive spectrometer, reveal a diverse range of microstructures, including continuous eutectic intermetallic phases and eutectic‐free configurations under different bonding conditions. Additionally, the interfacial diffusion of IN718/BNi‐2 is simulated by molecular dynamics. Notably, higher mass fractions of Cr in the interlayer are found to prolong the time of isothermal solidification. The use of BNi‐2 interlayers, 50 μm in thickness, results in joints achieving isothermal solidification within a remarkably brief 10 min, a significantly shorter duration compared to previous studies. Mechanical tests, encompassing microhardness and uniaxial tensile experiments, are carried out on all samples. The microhardness of the isothermally solidified zone decreases with increasing bonding time. The tensile strength of bonded joints increases with extended bonding time before isothermal solidification completion, followed by a subsequent decline. The highest tensile strength (893.3 MPa) is observed in joints using BNi‐2 interlayer after applying postbond heat treatment, representing approximately 88.5% of the base metal tensile strength. [ABSTRACT FROM AUTHOR]

Compared with LiFePO4 materials, manganese-based olivine is a promising cathode candidate with high energy and low cost for Li-ion batteries (LIBs). Its rate capability and cyclability challenges still remain even with nano-size and carbon coating. Herein, a high-rate performance is achieved by introducing a novel carbon coating source, poly propylene glycol (PPG 2000). Compared with traditional glucose carbon coating source, it is found that PPG facilitates a highly uniform conductive carbon coating during the carbonized process. Moreover, laser particle size analyzer also suggest that PPG 2000 can act as a highly effective dispersant, which can result in finer primary particles during grinding. Therefore, electronic and ionic conductivity are greatly improved so that the highly Li+ conductive nature of olivine materials can be fully unleashed. The final LiMn0.6Fe0.4PO4/C materials can deliver a capacity of 120 mAh·g−1 even at 10 C rate. This work demonstrates the importance of novel carbon coating source to the active cathode particles and opens upon a new venue for the large-scale fabrication of manganese-based olivine cathode materials. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) and its alloys face challenges in clinical applications due to their high degradation rates and low antibacterial properties. To overcome these challenges, this study employed an electrolyte containing elements such as F, Ca, P, Si, Sr, and Ag to perform soft spark micro-arc oxidation (MAO) on ZrO2–AZ91D Mg alloy. The research encompassed analysis of the MAO process, characterization of the composite coating's phase composition and elemental valence states, measurement of the physicochemical properties of the coating, as well as evaluation of biological properties including cell adhesion, protein adsorption, cytotoxicity, and antibacterial activity. This study investigated the mechanisms underlying osteogenesis and antibacterial effects of co-doped coatings, and examined the influence of bioactive elements on the performance of MAO coatings. The results demonstrated that the co-doped F/Ca/Sr/Ag particle-containing MAO composite coating exhibited excellent wettability and corrosion resistance. Additionally, the coating displayed remarkable protein adsorption capacity, superior adhesion to MC3T3-E1 osteoblast cells, and excellent antibacterial efficacy against Staphylococcus aureus, all while showing negligible toxicity. [ABSTRACT FROM AUTHOR]

Transition metal nitride negative electrode materials with a high capacity and electronic conduction are still troubled by the large volume change in the discharging procedure and the low lithium ion diffusion rate. Synthesizing the composite material of F-doped Fe3N and an N-doped porous carbon framework will overcome the foregoing troubles and effectuate a preeminent electrochemical performance. In this study, we created a simple route to obtain the composite of F-doped Fe3N nanoellipsoids and a 3D N-doped porous carbon framework under non-ammonia atmosphere conditions. Integrating the F-doped Fe3N nanoellipsoids with an N-doped porous carbon framework can immensely repress the problem of volume expansion but also substantially elevate the lithium ion diffusion rate. When utilized as a negative electrode for lithium-ion batteries, this composite bespeaks a stellar operational life and rate capability, releasing a tempting capacity of 574 mAh g–1 after 550 cycles at 1.0 A g–1. The results of this study will profoundly promote the evolution and application of transition metal nitrides in batteries. [ABSTRACT FROM AUTHOR]

Amorphous alloys show interesting mechanical properties as well as unique physical and chemical properties due to their atomic stacking structure. However, when partial crystallization occurs in amorphous alloys, it can impact the properties of the original amorphous alloy. To study the crystallization phenomenon in the Zr-based amorphous alloy, a three-dimensional Zr-based amorphous alloy atomic-stacking model was established by molecular dynamics simulations, and the atomic structure evolution of the Zr-Cu amorphous system after partial crystallization was analyzed by the radial distribution function g(r), HA bond index and Voronoi polyhedron. The results showed that adding more copper (Cu) atoms to the Zr-Cu amorphous system greatly improves its stability at high temperatures. The atomic diffusion was analyzed by root-mean-square displacement of atoms (MSD); as the temperature rose, the MSD of atoms also increased, suggesting that the crystallization of the amorphous material occurs due to the short-range diffusion of atoms. The analysis of the mechanism of the high-temperature action time on the Zr80Cu20 amorphous alloy showed that the crystallization phase precipitation rate of the amorphous alloy gradually increases with time, but it does not change linearly. [ABSTRACT FROM AUTHOR]