Progress in Natural Science: Materials International
ISSN / EISSN : 1002-0071 / 1745-5391
Published by: Elsevier BV (10.1016)
Total articles ≅ 2,501
Latest articles in this journal
Progress in Natural Science: Materials International; doi:10.1016/j.pnsc.2021.06.012
The roles of Al11Sm3 and Al2Sm phases on microstructure evolution, mechanical properties and corrosion behavior of the Mg-5Sm-xAl system was investigated. The results showed that adding Al to Mg–5Sm binary alloy brought two Al–Sm phases, Al11Sm3 and Al2Sm, which had two distinct roles regarding the microstructure evolution, mechanical properties and corrosion behavior of the Mg-Sm-Al alloy. Al11Sm3 produced a strong galvanic couple with the Mg matrix, and significantly accelerated the corrosion. The Al2Sm particles promoted heterogeneous nucleation and refined the grains, which increased the tensile strength and ductility. Both types of Al–Sm particles provided strengthening effect for the alloy. With higher Al contents, Al2Sm formed an Al oxide protective surface layer and increased corrosion resistance.
Progress in Natural Science: Materials International; doi:10.1016/j.pnsc.2021.07.006
As two important members of complex hydrides, Mg(BH4)2 and NaBH4 have a high gravimetric capacity (14.9 and 10.8 wt%, respectively). In this study, the Mg(BH4)2 was synthesized by the ion exchange method. Afterwards, the Mg(BH4)2 and NaBH4 composites with different amounts (30, 40 and 50 wt%) of NdF3 were prepared by mechanical milling. Effects of the NdF3 on the microstructural evolution and hydrogen storage properties were investigated. The results show that NdF3 catalyst can significantly improve the dehydrogenation kinetics of the eutectic composites of NaBH4–Mg(BH4)2. The onset hydrogen desorption temperature of the composites is about 88.6 °C, which is about 110 °C lower than that of Mg(BH4)2 and NaBH4 composites. Mg(BH4)2–NaBH4-0.5NdF3 composites can released 5.2 wt% H2 at 250 °C within 30 min, and the dehydrogenation capacity is significantly higher than that of Mg(BH4)2–NaBH4 composites. The analysis of the dehydrogenation mechanism reveals that NdF3 takes participate in the reaction to generate NaMgF3 to promote the dehydrogenation reaction process of the composites.
Progress in Natural Science; doi:10.1016/j.pnsc.2021.06.007
To promote substantially the performances of red phosphorous (P) anode for lithium and sodium-ion batteries, a simple plasma assisted milling (P-milling) method was used to in-situ synthesize SeP2/C composite. The results showed that the amorphous SeP2/C composite exhibits the excellent lithium and sodium storage performances duo to the small nano-granules size and complete combination of selenium (Se) and phosphorous (P) to generate Se–P alloy phase. It was observed that inside the granules of SeP2/C composite the nanometer size of the SeP2 particles ensured the fast kinetics for Li+ and Na+ transfer, and the amorphous carbon wrapping the SeP2 particles relieved volume expansion during lithium/sodium storage processes and enhances electric conductivity. Therefore, the SeP2/C electrode retained reversible capacities of 700 mA h g−1 at 2 A g−1 after 500 cycles and 400 mA h g−1 at 0.5 A g−1 after 400 cycles as anode for LIBs and SIBs, respectively. The result proves that the amorphous SeP2/C composite can be a new type of anode material with great potential for lithium and sodium-ion batteries.
Progress in Natural Science: Materials International; doi:10.1016/j.pnsc.2021.06.003
Anatase TiO2 nanotubes array (ATONA) has attracted tremendous attention owing to its promising applications in solar cells, water splitting and organic pollutants photocatalytic degradation. However, the activity of ATONAs was greatly suppressed by the grain boundaries existed in the tube walls, which acted as carrier scattering and recombination centers. Herein, we report a novel strategy to prepare array of single crystalline anatase TiO2 nanotubes (SC-ATONAs) with significant enhancement of the photocatalytic activity and UV photo response performance compared to the polycrystalline counterparts. The growth of SC-ATONAs was achieved by establishing a crystallization temperature gradient along the tube wall, which ensured the crystallization started from the nucleation of a single nucleus at the bottom of amorphous TiO2 nanotubes prepared by Ti anodization. These findings pave the way to prepare single-crystalline nanotubes with superior performance for other materials.
Progress in Natural Science: Materials International; doi:10.1016/j.pnsc.2021.07.005
Combination of hot isostatic pressing (HIP) and rejuvenation heat treatment (RHT) technology was used to restore creep-damaged DZ125 directional solidified superalloy, and the influence of microstructure restoration on high temperature fatigue behavior of the samples was explored. The results show that the HIP+RHT process could effectively heal internal cavities and recover the degraded γ′ phase in creep-damaged DZ125 superalloy to cubic particles similar as in as-received sample. After restoration treatment, the stress concentration areas inside the sample eradicated with the healing of the internal cavities, and the fatigue source areas were limited only to near surface than initiating from inside as in the as-received and creep-damaged samples. As a result, the restored sample had higher crack initiation life and lower crack propagation rate compared to as-received and creep damaged samples. The TEM microstructure characterization near fatigue fracture showed that the restoration of the degraded γ′ phase eliminated tangled dislocation in creep damaged sample and produced evenly distributed dislocations in the γ channel with short curved line-like morphology, like the as-received sample, which effectively hindered the dislocations movement during subsequent deformation, and strengthen the fatigue resistant of alloy. Therefore, it can be concluded that the HIP-RHT process, through the combined effect of internal cavities healing and the restoration of the degraded microstructures, renders higher high temperature fatigue life than creep-damaged and even higher than as-received DZ125 superalloy.
Progress in Natural Science: Materials International; doi:10.1016/j.pnsc.2021.07.007
The dielectric performances as well as the effects of Dy3+ ions content at A sites of YMn2O5 (YMO) [x = 0 (YDM0) and x = 0.4 (YDM0.4)] polycrystalline samples were explored. These compounds were synthesized via sol–gel method. X-Ray diffraction and Raman measurements proved the high quality of the compounds that crystallized in an orthorhombic structure with the Pbam space group. Besides, impedance spectroscopy and electrical modulus studies revealed that both samples exhibited a non-Debye's type of relaxation. The decrease of impedance for YDM0.4 compared to the pure YDM0, may be attributed to the decrease in charge transfer resistance. Concerning the fit of impedance spectra, they confirmed that both compounds were simultaneously capacitive and resistive. Furthermore, the activation energies obtained from Modulus and complex impedance were proven to be neighboring, suggesting that the relaxation process refers to electron hopping. For each compound, the evolution of ε' and tan δ with temperature indicated a clearer relaxor behavior, namely the existence of two relaxations. The first one detected at low temperature is related to the charge carriers hopping between Mn3+ and Mn4+ and the second at high temperature is associated with oxygen vacancies. The reduced hopping rate with Dy3+ substitution for Y3+ ions at A sites is responsible for the decrease in dielectric constant and dielectric loss. These significant findings demonstrate that these materials can be invested in a fruitful use in UV photo-detector and power applications in high frequency as microwave, millimeter wave signal processing, for civilian, military and space applications.
Progress in Natural Science: Materials International; doi:10.1016/j.pnsc.2021.06.011
The increasing demand for portable and flexible energy storage devices drives the development of flexible electrodes and electrolytes. The aim of this work is to fabricate the flexible free-standing polyaniline/poly (vinyl alcohol) (PANI/PVA) composite electrode with good capacitance performance and shape memory behavior. The electrodes were fabricated by chemical oxidation polymerization of aniline in porous PVA (P-PVA) films. The morphology, electrochemical and mechanical properties of PANI/P-PVA electrodes were studied by scanning electron microscope, cyclic voltammetry, galvanostatic charge-discharge, and tensile test etc. The results revealed that the flexible PANI/P-PVA-1 electrode had good specific capacitance of 173.86 mF cm−2 at 1 mA cm−2, with the capacitance retention of 70.16% after 4000 charge-discharge cycles. Besides, it had excellent heat-induced shape memory effect. The fixed shape could completely recover to its original shape within 10 s at 80 °C, which is above the glass transition temperature (75.89 °C) of PANI/P-PVA-1. The comparatively tensile strength (2.86 MPa) and high elongation at break (315.72%) indicated its outstanding flexibility. Up to 200 times folding had no effect on the electrochemical properties. The free-standing polymer electrodes with excellent comprehensive performance provide potential applications in flexible energy-storage devices, electronic encapsulation and high stretchable electric devices etc.
Progress in Natural Science: Materials International; doi:10.1016/j.pnsc.2021.03.003
Ring-opening polymerization of N-carboxyanhydrides (NCAs) bearing pendant groups creates functional polypeptides. In this paper, we report the design, synthesis and polymerization of tetraphenylethylene (TPE)-modified NCA, which is used to incorporate aggregation-induced emission (AIE)-active segments into polypeptides. Specifically, we attempted the synthesis of amphiphilic methoxy poly(ethyleneglycol)-block-poly(γ-benzyl-l-glutamate)-block-poly(γ-4-(1,2,2-triphenylvinyl)benzyl-l-glutamate) (PEG-PBLG-PTPELG), which had well-controlled molecular weight and narrow polydispersity. The hydrophilic PEG and hydrophobic PBLG-PTPELG assembled into micelles in aqueous solution with diameter around 70 nm, displaying AIE at 480 nm. Our work demonstrates that the TPE-modified NCA is applicable for the preparation of the AIE-active polypeptides, integrating the AIE luminogens into the polypeptides which may offer unique opportunities for tuning AIE properties by adjusting the composition and conformation of polypeptides. We preliminarily explored the use of the amphiphilic polypeptides for the formulation of doxorubicin-containing micelles that can potentially be used for real-time monitoring of the nanomedicine distribution.
Progress in Natural Science: Materials International; doi:10.1016/j.pnsc.2021.06.010
Ba2SmTaO6 laser protection coatings of ≈200 μm thickness were deposited onto stainless steel surfaces by air plasma spraying, and the laser irradiation resistance of the coatings was investigated. For laser irradiation with a laser power density less than 1000 W/cm2, the coatings kept intact. For a laser power density exceeding 1500 W/cm2, the Ba2SmTaO6 coatings underwent recrystallization, grain growth occurred, and certain spray morphology features disappeared by melting. In the case of a laser power density of 2000 W/cm2 applied for 10s, the incident laser parameter was beyond the coatings protection threshold, and the coating peeled off. The samples back surface temperature kept unchanged within the first 1s of laser irradiation, indicating that Ba2SmTaO6 coatings have excellent laser protection capability and can limit the rise of the substrate temperature. However, the low thermal conductivity of Ba2SmTaO6 leads to a detrimental laser energy concentration at the beginning of the laser irradiation period on the sample front surface, resulting in a rapid increase of the surface temperature up to the melting point.
Progress in Natural Science, Volume 31, pp 428-433; doi:10.1016/j.pnsc.2021.04.009
The multi-phase-field (MPF) model coupled with reliable CALPHAD thermodynamic/atomic mobility descriptions, appropriate faceted anisotropy and key experimental validation is employed to perform the quantitative simulation of the microstructure evolution of the hypereutectic Al-16 wt%Si alloy during solidification. By considering the effect of latent heat released during the eutectic phase transformation in the simulation, the appropriate entire solidification sequence is obtained. All the characteristics in the as-cast microstructure can be nicely reproduced, including the primary (Si) encircled by the second primary (Al) halo, and the coupled eutectic grains appearing at the Liquid/(Al) interface rather than Liquid/(Si) interface. Moreover, three types of growth patterns of eutectic (Si) with different lengths are distinguished according to the distance between primary (Si) and the nucleation position of eutectic (Si). Furthermore, the evaluated ratios of width to length for 50 eutectic (Si) grains due to the MPF simulation are in good agreement with the experimental data. The quantitative phase-field simulation of the entire solidification process of the hypereutectic Al-16 wt%Si alloy in the present work is anticipated to pave the way for revealing the grain refinement mechanism in hypereutectic Al–Si alloys in the future studies.