Journal of Materials Engineering and Performance最新文献

Fe-Al intermetallic compounds have received much attention as one of the high-temperature structural materials. In the present study, Fe(Al, Ta)/Fe₂Ta(Al) eutectic composites were prepared using the electron beam floating zone melting (EBFZM) directional solidification technique. Room and high-temperature tensile properties of the Fe(Al, Ta)/Fe₂Ta(Al) eutectic composites at different solidification rates were studied. Microstructure evolution and fracture mechanism during the fracture process were analyzed using in situ tensile tests. The results show that lamellar (rodlike) Fe₂Ta(Al) Laves phase becomes finer and more uniform with the increase in the solidification rate. The tensile strength of the Fe(Al, Ta)/Fe₂Ta(Al) eutectic composite increases with the increase in the solidification rate at the same tensile temperature. The tensile strength of the Fe(Al, Ta)/Fe₂Ta(Al) eutectic composite at 600 °C is weaker than that at room temperature at the same solidification rate. The fracture mechanism of the Fe(Al, Ta)/Fe₂Ta(Al) eutectic composite can be summarized as crack extension along the shear zone, crack passing through the Laves phase, crack extension along the phase interface and simultaneous extension of multiple cracks.

This study introduces a novel design for a 3D-printed nozzle neck with integrated deformation-absorbing cavities, aimed at mitigating drive torque caused by thermal deformation and mechanical interference in solid propellant motors. Fabricated using metal 3D printing technology with a tungsten-copper alloy, the nozzle neck was verified using 3D CT scanning to ensure precise realization of the internal cavities according to the design. This approach addresses the limitations of traditional machining by enabling complex internal structures while preserving external geometry. Experimental results demonstrated a 37.2% reduction in drive torque at a 400 μm interference distance compared to a baseline WCu nozzle neck. Finite element analysis (FEA) further confirmed that the internal cavities effectively dissipate mechanical stress and deformation, significantly decreasing frictional forces and drive torque. The findings suggest that deformation-absorbing cavity structures, enabled by advanced 3D printing, can enhance component durability under mechanical interference, offering significant improvements for high-performance aerospace applications.

Welding residual stress significantly impacts fatigue and stability in engineering applications. The vibratory stress relief (VSR) treatment offers an efficient and flexible method for releasing residual stress, particularly in welded structural components. This research investigates how VSR treatment influences the residual stress and impact toughness in welded joints of Q235 steel. VSR treatment was applied to Q235 steel specimens, and Charpy impact tests were performed on them both with and without the treatment. Scanning electron microscopy (SEM) was used to analyze the fracture morphology of the welded joints, and the Vickers microhardness of Q235 steel-welded joints was tested with and without VSR treatment. With the help of ABAQUS finite element software, a numerical model for Q235 steel welding was set up, and the effect of VSR on residual stress was analyzed in combination with residual stress measurements by the hole-drilling method. Research indicates that VSR treatment enhances the impact toughness of welded joints by 36.04% compared to untreated samples, with a notable decrease in residual stress levels, thereby reducing stress concentration effects. Fracture morphology and residual stress simulations confirm that VSR treatment homogenizes internal stress and significantly improves impact toughness.

Recently, researchers have progressively focused on the corrosion of biomedical implants and the leaching of metal ions into body fluids. To enhance the corrosion and wear resistance of metal implants, Titanium Nitride (TiN) coatings have been suggested as a viable option due to their high hardness and corrosion resistance. In the present study, TiN was formed on a Ti-6Al-4V alloy using the hollow cathode plasma nitriding process in N₂-H₂ gaseous mixture at 800 °C for 8 h. The microstructural and structural properties of the TiN layer were characterized by scanning electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. To study the corrosion behavior of this alloy, potentiodynamic polarization and electrochemical impedance measurements were conducted in three different simulated solutions (3.5wt.% NaCl, Hank’s solution and artificial saliva). Electrochemical studies revealed that the plasma nitrided Ti-6Al-4V alloy exhibited superior corrosion resistance properties compared to the pristine Ti-6Al-4V alloy in all three simulated solutions. However, the corrosion resistance of both untreated Ti-6Al-4V and plasma nitrided Ti-6Al-4V alloy was found to be lower in artificial saliva solution compared to the other solutions. Additionally, the plasma nitrided Ti-6Al-4V alloy showed reduced metal ion release in the simulated solutions. Based on these findings, it can be concluded that the plasma nitrided Ti-6Al-4V alloy holds a great potential as an implant material in the medical field.

Molybdenum alloy single crystals with excellent creep performances are key materials for nuclear power generation components. However, there are few reported molybdenum alloy single crystals, and the research on their creep properties is limited due to the difficulty in material preparation and the huge cost in creep experiment. In this paper, room temperature creep of novel Mo_96.18Nb_3.61W_0.21 single crystals was investigated under different nanoindentation loading rates, and creep deformation behavior was analyzed from the view of work–energy conversion. With the rising of nanoindentation loading rate, work hardening was significantly enhanced, and more deformation energy was stored in the single crystals. The stored energy rapidly released in the early stage of creep, resulting in a notable increase in the creep displacement. Although the creep deformation of (110), (111), and (112) oriented single crystals was dominated by dislocation movement, yet their creep performances exhibited evident anisotropy due to the difference in atom arrangement. The (111) orientation of Mo_96.18Nb_3.61W_0.21 single crystals has the best creep resistance among the mentioned orientations according to the comprehensive analysis results on creep displacement, creep strain rate, strain rate sensitivity, and activation volume.

This study investigates the aging behavior of carbon-fiber-reinforced brominated bisphenol-A epoxy vinyl ester resin (CFBPA), a marine-grade composite material, through long-term natural exposure testing in Qingdao’s marine atmosphere. Using a comprehensive analytical approach incorporating Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and tensile testing, we systematically characterized the evolution of the chemical, morphological, thermal, and mechanical properties of CFBPA under environmental stressors. The results demonstrated that UV radiation initiates significant resin matrix degradation, whereas prolonged exposure exacerbates carbon fiber deterioration, collectively impairing the mechanical performance of the composite. Microscopic analysis revealed that matrix delamination was predominantly initiated at the fiber–matrix interface. These findings provide critical insights for the development of enhanced environmental protection strategies for marine composite applications, particularly for optimizing interfacial bonding and UV-resistant formulations.

In this study, the effects of heat treatment on the mechanical and corrosion performance of Cu-P-Ag alloys were systematically investigated with the aim of achieving an optimized balance between flexibility, mechanical strength, and electrochemical stability. Cu-P-Ag alloys are widely used in industrial brazing and electronic applications due to their high electrical conductivity, thermal performance, and corrosion resistance. However, improving mechanical strength often compromises flexibility and increases residual stress causing early fractures during production. To address this challenge, the alloy was subjected to controlled heat treatments at various temperatures (100 to 550 °C). Microstructural evolution was analyzed via SEM and XRD, while hardness and residual stress measurements provided insights into mechanical behavior. The results reveal that heat treatment at 400 °C significantly enhances flexibility and reduces internal stress, primarily due to the uniform and fine precipitation of β-Ag phases and the formation of a uniform and thermodynamically stable microstructure. In parallel, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and Mott–Schottky analysis were employed to assess corrosion resistance in 0.9% NaCl solution. The findings indicate that the passive films formed post-treatment at 400 °C exhibit superior protective characteristics, attributed to improved film compactness and reduced surface heterogeneity. This optimized heat treatment condition successfully enhances both mechanical and electrochemical performance, making the Cu-P-Ag alloy more suitable for high-performance industrial applications where strength, softness, and corrosion resistance need to be balanced.

The regulation of the microstructure in as-cast dual-phase Mg-Li alloy through heat treatment not only enables the attainment of superior mechanical properties but also facilitates the preparation of the microstructure for subsequent severe plastic deformation. In the study, the microstructure of the Mg-7Li-6Al-2Ca-0.5Mn (LACX7620) alloy was examined using scanning electron microscopy (SEM), x-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). The analysis revealed the presence of several phases in the as-cast alloy: α-Mg, β-Li, Al₂Ca, AlLi, MgAlLi₂, and Al-Mn (W phase). After solution treatment at 200 °C for 2 hours, the AlLi and MgAlLi₂ phases in the alloy migrated toward the grain boundaries, resulting in a more uniform microstructure. Compared to other heat treatment methods, the alloy exhibited a remarkable increase in tensile strength, rising from 71.74 to 155.05 MPa, a 116% improvement. Yield strength also increased significantly, from 67.27 to 124.12 MPa, corresponding to an 84% increase. Additionally, elongation was notably enhanced. The optimal phase stability and strength were achieved through solid solution treatment at 200 °C for 2 hours.

Glass samples of CuO/Fe₂O₃ reinforced bismuth borate containing ZnO and NaF with the chemical form 65B₂O₃-15NaF-15ZnO- 5Bi₂O₃-XFe₂O₃- YCuO: (X,Y) = (0.0,0.0) {S0}, (0.1, 0.4) {S1}, (0.2, 0.3) {S2}, (0.3, 0.2) {S3}, (0.4, 0.1) {S4}, and (0.5, 0.0) {S5} mol.% were prepared via melt quenching procedure. The influence of CuO/Fe₂O₃ on the structure, physical properties, and γ-ray attenuation capability was examined. The non-crystallinity nature of samples was confirmed by XRD measurements and SEM images. The density (D_s) of samples increased from 3.10 to 3.30 g/cm³ as Fe₂O₃concentration increase from 0.0 to 0.5 mol.%. The molar volume (V_m) declined from 28.05 to 26.62 cm³/mol. The parameter of oxygen packing density (OPD) enhanced from 80.20 to 85.09. The oxygen molar volume (OMV) changed as 12.47 cm³/mol for S0 sample and 11.75 cm³/mol for S5 sample. Direct (E_opt-direct) and indirect (E_opt-indirect) optical band gaps decreased with doping with Fe⁺³ and Cu²⁺ ions in the glass networks. E_opt-direct decreased from 3.685 to 3.620 eV, while E_opt-indirect varied between 3.642 and 3.595 eV. Undoped sample S0 exhibited a broad strong UV absorption which related to unavoidable trace ferric ions, Fe³⁺ ions, impurities contaminated within the raw materials used for the preparation of the glasses. For doped glasses UV-visible bands due to doping with 3d transition metal ions. In terms of γ-ray shielding, linear (LAC) absorption coefficient followed the order: S0_LAC < S1_LAC < S2_LAC < S3_LAC < S4_LAC < S5_LAC. The S5 glass sample has the lowest half value layer (HVL) and mean free path (MFP). The effective atomic number (({text{Z}}_{text{eff}})) has the same trend of MAC. The suggested S5 sample presents the best γ-ray shielding capability among the investigated samples. Results confirm that the sample coded as S5 is superior as γ-ray shields compared to ordinary concrete (OC) and RS-253-G18 glasses.