Journal of Materials Science最新文献

Biodegradable pseudo-proteins (PPs), a novel class of synthetic polymers mimicking natural proteins, offer unique advantages for biomedical applications, including superior biocompatibility, tuneable degradation, and structural versatility. In this study, we investigate the mechanical and microstructural behavior of two representative PPs—poly(ester amide) (PEA) and poly(ester urea) (PEU)—using a novel in situ stretching technique combined with nanobeam wide-angle X-ray scattering (WAXS). This advanced methodology enables real-time, submicron-resolution analysis of molecular ordering during mechanical deformation. For both PEA and PEU, the WAXS patterns two distinguished (001) and (010) peaks associated with lamellar stacking and chain–chain packing of aliphatic segments, correspondingly. Our results reveal that PEA, characterized by higher crystallinity of the (010), exhibits brittle fracture under stress, whereas PEU demonstrates elastic behavior due to its lower (010) crystalline content and greater chain mobility. These findings establish a direct correlation between sectional crystallinity and mechanical performance, providing valuable insights for the rational design of PPs with tailored properties for biomedical use.

Implant-related infections are a significant and urgent problem in clinical medicine, which need to be addressed for a long time. Here, we designed a new type of low-cost, low elastic modulus, non-toxic, and easily manufacturable Ti–Zr–Nb–Mo series biomedical β-Ti alloy through machine learning methods and introduced Cu elements to impart antibacterial functionality to the alloy. The Ti_54−xZr₁₅Nb₁₄Mo₁₇Cu_x (x = 1, 3, 5, 7 at.%) alloys achieved excellent mechanical properties with an ultra-low modulus. Moreover, the Ti_54−xZr₁₅Nb₁₄Mo₁₇Cu_x alloys can inhibit both Staphylococcus aureus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria). The potent antibacterial effect originates from the disruption of the bacterial cell wall structure induced by the reactive oxygen species (ROS). In addition, the Ti_54−xZr₁₅Nb₁₄Mo₁₇Cu_x alloys also exhibit excellent biocompatibility performance, which is beneficial for the clinical application. This work suggests that Ti_54−xZr₁₅Nb₁₄Mo₁₇Cu_x alloy implants have potential practicality in treating orthopedic infections.

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Sb-Zn-based alloys are interesting for low-temperature thermoelectric applications. For the enhancement of thermoelectric properties, indium is seen as a promising alloying addition. The knowledge of the ternary In-Sb-Zn alloys solidification path is important for synthesis of materials with required properties. Thirty In-Sb-Zn alloys were prepared, and their as-cast microstructures were analysed. Alloys were produced by melting high-purity components in evacuated quartz ampoules, and their microstructures were characterized by scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS) and x-ray diffractometry (XRD). Liquidus projection of the ternary In-Sb-Zn system is determined based on experimental results and phase diagrams of limiting binary systems. There are nine primary solidification phase regions. In addition to terminal solution phases and five binary compounds, one ternary compound exists in the system: Zn₅Sb₄In₂.

The review delves into the optical and luminescence features of borate- and tellurite-based glasses doped with Holmium (Ho³⁺) and Praseodymium (Pr³⁺) ions, emphasizing their potential for diverse applications. Borate glasses, known for their high ultraviolet transparency and low phonon energy, effectively host Ho³⁺ and Pr³⁺ ions and exhibit emissions in the infrared (IR) and visible regions. Tellurite glasses have a high refractive index and broad infrared transparency, resulting in enhanced emission intensity and efficient radiative decay of Ho³⁺ and Pr³⁺ ions. The borate–tellurite amalgamation leads to thermal stability and optical clarity of borate with a high refractive index and broad IR transmission of tellurite, resulting in glasses with improved luminescence and color purity. Holmium ions embedded in glass matrices emit light in the near-IR and visible range, making them suitable for IR sensors and medical laser systems. Praseodymium-doped glasses exhibit emissions in the visible spectrum, particularly in the red and blue regions, making them valuable for display devices and optical amplifiers. The incorporation of Ho³⁺ and Pr³⁺ ions also influences the optical band gap, refractive index, and radiative lifetimes, offering a wide variety of tailored features. Therefore, the optical characteristics of borate, tellurite, and borotellurite glasses doped with Ho³⁺ and Pr³⁺ ions have gained substantial interest in applications of photonics and optoelectronics. Combining borate and tellurite results in borotellurite glasses doped with Ho³⁺ and Pr³⁺ ions, which have high luminescence efficiency and stability and are ideal for applications in lasers, fiber amplifiers, display technologies, and sensors. The investigation of the luminous properties of these glasses, which have been influenced by phonon interactions and glass composition, reveals their promise in developing next-generation optical devices and photonic applications.

Mechanical and physical properties are key toward characterizing membrane performance, especially in applications requiring structural integrity, chemical resistance, and thermal stability. In the present study, the PVDF and PVDF-co-HFP membranes have been prepared through phase inversion with changing polymer concentrations (10, 15, and 20 wt%) and membrane thicknesses (50–150 μm) for their morphological, thermal, mechanical, and wettability characterizations. SEM analysis demonstrated a distinct morphological transition in the PVDF membranes, where the structure evolved from open macrovoids to a denser, sponge-like form as the polymer concentration increased. In contrast, the PVDF-co-HFP membranes exhibited larger and more interconnected macrovoids, contributing to enhanced mechanical flexibility. Contact angle measurements ranged from 56° to 79° for PVDF and 49°–85° for PVDF-co-HFP membranes, indicating tunable surface hydrophilicity. Porosity evaluation further revealed that PVDF-co-HFP membranes consistently exhibited higher porosity values (80% and 79%, respectively) than pure PVDF, even at higher polymer concentrations, due to the enhanced phase separation facilitated by the flexible HFP segments. The shrinkage test presented the maximum 58% area loss for the PVDF10/10 sample at 50 °C, while the other PVDF and all the PVDF-co-HFP membrane samples presented < 20% shrinkage, demonstrating high-dimensional stability. The thermal degradation presented three-step decompositions, with the PVDF and the PVDF-co-HFP proposing total weight losses of 88% and 85%, respectively, while the PVDF-co-HFP presented delayed onset of the degradation. Mechanically, the maximum tensile strength was presented by the PVDF20/15 with 9.2 MPa, while the maximum elongation at break was presented by the membrane sample of the PVDF-co-HFP15/15 with strain values 1.99, supporting improved flexibility. In general, the PVDF-co-HFP membrane provides balanced thermal resilience, mechanical strength, and wettability control, appropriate for advanced membrane applications.

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Cu/Al₂O₃ composite catalysts have been widely researched within the category of Cu-based catalysts for CO₂ hydrogenation to synthesize methanol. However, issues such as low activity of copper during the catalytic process have been a significant concern. To address these issues, optimizing the interaction between Cu and Al₂O₃ particles can be a viable solution. This paper presents four synthesis methods to prepare the catalyst, including hydrothermal technique, grinding-calcination technique, impregnation technique, and co-precipitation technique. Notably, the Cu/Al₂O₃-HT catalyst, prepared via the hydrothermal method, exhibits the highest specific surface area and strongest basic adsorption sites. Compared with catalysts produced by other methods, it features a flower-like microspherical structure and an increased surface area, providing more effective reactive active sites that can facilitate the adsorption and activation of carbon dioxide on the catalyst surface. Moreover, in situ infrared spectroscopy is conducted on the Cu/Al₂O₃ catalyst prepared via hydrothermal method, revealing that the catalyst favors the synthesis of methanol through the formic acid pathway. This work presents a new approach to improving catalyst structure for CO₂ hydrogenation.

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The development of additive manufacturing (AM) technique has enabled unprecedented flexibility in the design and fabrication of complex metal components. However, the AM process is prone to defects like poor surface quality, high porosity, and tensile residual stress (TRS), which adversely affect the mechanical performance and service life of the fabricated components. Laser shock peening (LSP) is an innovative surface plastic strengthening technique that can effectively introduce compressive residual stresses (CRS) and refine microstructure, thereby mitigating these shortcomings. This paper first presents the principle and development of LSP and its research advancements in AM metals. It then systematically elucidates the effects of LSP in AM metals from two perspectives: the LSP post-treatment process and the AM + LSP hybrid process. Additionally, some investigations of LSP applications on specialized AM structures are introduced. Through a comprehensive review of research progress and technical challenges, research prospects are provided on theory, equipment, processes, performance evaluation, and technical standards to clarify the theoretical support and key technologies for future engineering applications.

Ti–12Mo–6Zr–2Fe (TMZF) alloy, characterized by its low elastic modulus and high strength-to-weight ratio, is a promising candidate for biomedical implants. However, its application in biomedical fields remains limited due to an incomplete understanding of the corrosion and tribological synergism in simulated body fluid (SBF). This study systematically investigates the phase composition, microstructural evolution, and biocorrosion and tribology behaviors of laser powder bed fusion (LPBF) fabricated TMZF alloys before and after solution treatment (ST). The optimal LPBF parameter was achieved at a linear laser energy density of 200 J/m, resulting in a relative density of 99.96% ± 0.02% and surface roughness of 5.27 μm, with porosity effectively suppressed. Following solution treatment at 900 ℃ for 1 h, the columnar grains of the LPBF-fabricated (AF TMZF) alloy recrystallized into equiaxed grains, and nanoscale orthorhombic α″ martensite phases precipitated within the β-phase matrix via stress-triggered martensitic transformation. This process was driven by two synergistic factors: (1) the high dislocation density and residual stress of LPBF alloy, and (2) local β-stabilizer depletion during ST. Consequently, AF TMZF exhibited a 69% lower corrosion current density (0.35 ± 0.02 vs. 1.16 ± 0.01 μA cm⁻²) and a 271% higher passive film impedance (0.26 vs. 0.07 MΩ cm²) in SBF than ST TMZF, attributed to its bimodal microstructure of fine equiaxed grains and nanoscale cellular substructures, combined with the inherent passivity of single-phase β-type Ti alloys. In contrast, the α″ phase precipitation in ST TMZF introduced interfacial heterogeneity, generating potential differences at boundaries between β and α″ phase that accelerated passive film rupture. Moreover, the ST TMZF exhibited enhanced microhardness and tribological performance in SBF solution, due to precipitation strengthening by α″ phase. This study elucidates how α″ phase precipitation modulates passive film formation and stability, establishing microstructure–property relationships for corrosion and tribology in LPBF TMZF, critical for its clinical adoption as a durable biomedical implant.

Solidification defects are critical and prevalent issues in the additive manufacturing of high-strength aluminum alloys. In this study, characteristics and formation mechanisms of solidification defects in additively manufactured high-strength 2A14 aluminum alloy were systematically investigated. Intergranular pores and coarse secondary phases appear at the crack tips, and intergranular cracks are formed by pore propagation along grain boundaries. Intergranular secondary phases play a key role in the formation of intergranular solidification defects. Increasing intergranular secondary phase content effectively suppresses the formation of intergranular pores and cracks, thereby significantly reducing the crack density in the 2A14 alloy, despite the presence of coarsened columnar grains, a high fraction of columnar grains, strong texture, and a consistently high fraction of high-angle grain boundaries, which are generally considered to increase crack susceptibility. These results suggest that regulating intergranular secondary phases is an effective strategy to eliminate intergranular solidification defects, particularly cracks. The findings provide theoretical support for the design of aluminum alloys for additive manufacturing.

In this study, cobalt coated alumina (Co@Al₂O₃) particles were prepared via the electroless plating process, and mixed with CoCrMo alloy powders in the proportion of 0.5–2 wt%. The Co@Al₂O₃/CoCrMo composites were then manufactured by selective laser melting (SLM) process. The microstructure, texture, wear resistance performance and mechanical property of the composites were characterized. By increasing the content of Co@Al₂O₃ particles from 0 to 1.0 wt%, a martensitic transformation from the γ phase to ε phase occurred, while the composites kept flawless with the lowest wear rate of 2.07 × 10^–5 mm³ N⁻¹ m⁻¹ and the highest ultimate tensile strength (UTS) of 1251.93 MPa. When the content of Co@Al₂O₃ particles increased further, both the wear rate and UTS of composites deteriorated unexpectedly, it is ascribed to the micrometer-scale pores from the gasification of organic matter in Co@Al₂O₃ particles during the SLM process, which have become the location of crack initiation and propagation.

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