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In this study, Bi2Se3 thermoelectric materials with high density, low thermal conductivity, and excellent thermoelectric performance are prepared using a Se slow-release method. It was found that the number of Se defects in the material could be effectively reduced by changing the content of NaCl solvent, and a certain number of Na atoms are introduced into the Bi2Se3 matrix. The carrier concentration of Bi2Se3 is greatly optimized due to the synergistic effect of the two, leading to a gradual increase in the Seebeck coefficient from −94 to −122 μV K−1 at room temperature. Simultaneously, we conducted an in-depth investigation into the effects of Na doping and Se vacancies on the electronic structure of the materials. Our findings indicate that the presence of these two defects gives rise to resonance energy levels and sharpens the density of state peaks near the Fermi level. This discovery further underscores the potential for enhancing thermoelectric performance. Finally, the Bi2Se3(NaCl)10 sample achieved the maximum ZT value of 0.69 at 550 K, and the average ZT within the temperature detection range reached 0.36, increasing the thermoelectric performance of the material. [ABSTRACT FROM AUTHOR]

The microstructure, tensile and fatigue behavior of a hot-rolled Ti50Zr alloy applied for dental implant were investigated. The commercial Ti16Zr alloy was taken as a reference material. The load vs. number of cycling curves of the one-piece type Ti16Zr and Ti50Zr dental implants were tested according to ISO 14801 standard testing methods. The results show that the yield strength and fatigue limit of Ti50Zr alloy are up to 1001±8 MPa and 500 ± 10 MPa, respectively, 23% and 32% higher than Ti16Zr alloy. The enhanced strength of Ti50Zr alloy is attributed to multiple mechanisms, including acicular martensite strengthening, Zr solid solution strengthening, nano-twins and dislocations strengthening. The maximum cycling loads of Ti50Zr implants in air, artificial saliva solution and with sand blasting plus acid etching (SLA) treated surface reach 400 N, 400 N and 350 N (5 × 106 cycles without failure), respectively, 33%∼75% higher than Ti16Zr implants. High surface roughness harms the fatigue performance of the Ti-Zr implants owing to the promotion role of notch-type defects to fatigue crack initiation. A corrosion-assisted fatigue process in artificial saliva solution under large load reduces the fatigue life of the Ti-Zr implants. Ti50Zr alloy is an ideal candidate material applied for dental implant with regards to its good biocompatibility, excellent mechanical properties and economic processing route. • Commercial Ti16Zr alloy and new Ti50Zr alloy used for dental implant. • Microstructures and strengthening mechanisms of Ti16Zr and Ti50Zr alloy. • Fatigue behavior of Ti16Zr and Ti50Zr alloy under different conditions. • Ti50Zr implant has better fatigue property than Ti16Zr implant. [ABSTRACT FROM AUTHOR]

Abstract: The influence of yttrium on the corrosion residual strength of an AZ91D magnesium alloy was investigated detailedly. Scanning electron microscope was employed to analyze the microstructure and the fractography of the studied alloys. The microstructure of AZ91D magnesium alloy is remarkably refined due to the addition of yttrium. The electrochemical potentiodynamic polarization curve of the studied alloy was performed with a CHI 660b electrochemical station in the three-electrode system. The result reveals that yttrium significantly promotes the overall corrosion resistance of AZ91D magnesium alloy by suppressing the cathodic reaction in corrosion process. However, the nucleation and propagation of corrosion pits on the surface of the 1.0wt.% Y modified AZ91D magnesium alloy indicate that pitting corrosion still emerges after the addition of yttrium. Furthermore, stress concentration caused by corrosion pits should be responsible for the drop of corrosion residual strength although the addition of yttrium remarkably weakens the effect of stress concentration at the tip of corrosion pits in loading process. [Copyright &y& Elsevier]

Abstract: The corrosion behavior of AZ91Ce alloy in the presence of sulfate-reducing bacteria (SRB) was investigated using a specially designed in-situ corrosion method. For comparison, AZ91 alloy was also studied under the same corrosion condition. It seemed that AZ91Ce alloy was susceptible to crystal boundary corrosion under SRB condition to some extent. A possible mechanism for the crystal boundary corrosion was proposed. The microstructure and corrosion morphologies of alloys were analyzed by optical microscope and SEM, and the corrosion products were detected by X-ray photoelectron spectrometer (XPS). The analysis results showed that Ce in AZ91 alloy can reduce the grain size, and impede the formation of oxide, and thereby improved the corrosion performance. The electrochemical test revealed that the formation of Ce compound can restrict the cathodic reaction, and thus improve the corrosion resistance significantly as observed under the sterile condition. However, it appeared that the improvement was unconspicuous in the presence of SRB. [Copyright &y& Elsevier]

Abstract: The compressive behaviors of Zn–22Al composite foams using SiC particles as reinforcement and stabilizing agent (ZA22/SiCp composite foams) were investigated in this study. To observe the deformation mechanisms, the deformation processes of the composite foams were recorded, and the cracks under the compressive load were observed by scanning electron microscope (SEM). Owing to the presence of the particles, ZA22/SiCp composite foams show more brittle compressive behavior with a large stress fluctuation than Zn–22Al alloy foams (ZA22 foams). The compressive processes of composite foams are characterized by the formation and propagation of the localized deformation band. The photomicrographs of the cracks indicate that a complicated effect of SiC particles on the compressive properties of the foams result in a high compressive strength. As a consequence, ZA22/SiCp composite foams exhibit slightly high energy absorption capacities, although low energy absorption efficiencies, as compared with ZA22 foams. [Copyright &y& Elsevier]