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The effectiveness of the room-temperature strengthening strategy for aluminum (Al) is compromised at increased temperatures due to grain and precipitate phase coarsening. Overcoming the heightened activity of grain boundaries and dislocations poses a significant challenge in enhancing the high-temperature strength through traditional precipitation strengthening. This study presents novel strengthening strategies that integrate intergranular reinforcements, intragranular reinforcements, refined grain, and stacking faults within an (Al2O3+Al3Ti)/Al composite prepared using sol–gel and powder metallurgy technology. Excellent high-temperature tensile properties are achieved; also, a remarkable fatigue performance at increased temperatures that surpasses those of other existing Al alloys and composites is revealed. These superior characteristics can be attributed to its exceptionally stable microstructure and the synergistic strengthening mechanisms mentioned above. This work offers new insights into designing and fabricating thermally stable Al matrix composites for high-temperature applications.

The advantage of 3D printing—that is, additive manufacturing (AM) of structural materials—has been severely compromised by their disappointing fatigue properties1,2. Commonly, poor fatigue properties appear to result from the presence of microvoids induced by current printing process procedures3,4. Accordingly, the question that we pose is whether the elimination of such microvoids can provide a feasible solution for marked enhancement of the fatigue resistance of void-free AM (Net-AM) alloys. Here we successfully rebuild an approximate void-free AM microstructure in Ti-6Al-4V titanium alloy by development of a Net-AM processing technique through an understanding of the asynchronism of phase transformation and grain growth. We identify the fatigue resistance of such AM microstructures and show that they lead to a high fatigue limit of around 1 GPa, exceeding the fatigue resistance of all AM and forged titanium alloys as well as that of other metallic materials. We confirm the high fatigue resistance of Net-AM microstructures and the potential advantages of AM processing in the production of structural components with maximum fatigue strength, which is beneficial for further application of AM technologies in engineering fields.

Background: Cholangiopathies comprise a spectrum of diseases without curative treatments. Pharmacological treatments based on bile acid (BA) metabolism regulation represent promising therapeutic strategies for the treatment of cholangiopathies. Gentiopicroside (GPS), derived from the Chinese medicinal herb Gentianae Radix, exerts pharmacological effects on bile acid metabolism regulation and oxidative stress.Objective: The present study aims to investigate the effect of GPS on 3,5-diethoxycarbonyl-1,4dihydrocollidine (DDC)-induced cholangiopathy.Methods: Two independent animal experiments were designed to evaluate the comprehensive effect of GPS on chronic DDC diet-induced cholangiopathy, including bile duct obliteration, ductular reaction, BA metabolism reprogramming, liver fibrosis, oxidative stress and inflammatory responses.Results: In the first pharmacological experiment, three doses of GPS (5, 25 and 125 mg/kg) were injected intraperitoneally into mice fed a DDC diet for 14 days. DDC induced a typical ductular reaction, increased periductal fibrosis and mixed inflammatory cell infiltration in the portal areas. GPS treatment showed dose-dependent improvements in the ductular reaction, BA metabolism, fibrosis, oxidative stress and inflammatory response. In the second experiment, a high dose of GPS was injected intraperitoneally into control mice for 28 days, resulting in no obvious histologic changes and significant serologic abnormalities in liver function. However, GPS inhibited DDC-induced oxidative stress, serum and hepatic BA accumulation, proinflammatory cytokine production, and immunocyte infiltration. Specifically, the GPS-treated groups showed decreased infiltration of monocyte-derived macrophages and CD4+ and CD8+ T lymphocytes, as well as preserved Kupffer cells.Conclusion: GPS alleviated chronic DDC diet-induced cholangiopathy disorder by improving the ductular reaction, periductal fibrosis, oxidative stress and inflammatory response. Its dosage-dependent pharmacological effects indicated that GPS warrants its further evaluation in clinical trials for cholangiopathy.

Coupling effects of fretting wear and cyclic stress could result in significant fatigue strength degradation, thus potentially causing unanticipated catastrophic fractures. The underlying mechanism of microstructural evolutions caused by fretting wear is ambiguous, which obstructs the understanding of fretting fatigue issues, and is unable to guarantee the reliability of structures for long-term operation. Here, fretting wear studies were performed to understand the microstructural evolution and oxidation behavior of an α/β titanium alloy up to 108cycles. Contact surface degradation is mainly caused by surface oxidation and the generation of wear debris during fretting wear within the slip zone. The grain size in the topmost nanostructured layer could be refined to ∼40 nm. The grain refinement process involves the initial grain rotation, the formation of low angle grain boundary (LAGB; 2°–5°), the in-situincrements of the misorientation angle, and the final subdivision, which have been unraveled to feature the evolution in dislocation morphologies from slip lines to tangles and arrays. The formation of hetero microstructures regarding the nonequilibrium high angle grain boundary (HAGB) and dislocation arrays gives rise to more oxygen diffusion pathways in the topmost nanostructured layer, thus resulting in the formation of cracking interface to separate the oxidation zone and the adjoining nanostructured domain driven by tribological fatigue stress. Eventually, it facilitates surface degradation and the formation of catastrophic fractures.

Cholestatic liver diseases are groups of hepatobiliary diseases without curative drug-based therapy options. Regulation of bile acid (BA) metabolism, hepatoperiductal fibrosis, and inflammatory response indicated present novel methods for the treatment of cholestatic liver disease. Costunolide (COS) from herb Saussurea lappaexerts a pharmacological effect of regulation of BA metabolism, liver fbrosis and inflammatory response. The present study aimed to clarify the pharmacodynamic effects of COS against the murine model of cholestatic liver disease.

Recently, the eutectic high-entropy alloy (EHEA), AlCoCrFeNi 2.1 , can reach a good balance of strength and ductility. The dual-phase alloy exhibits a eutectic lamellar microstructure with large numbers of interfaces. However, the role of the interfaces in plastic deformation have not been revealed deeply. In the present work, the orientation relationship (OR) of the interfaces has been clarified as the Kurdjumov-Sachs (KS) interfaces presenting 111 B 2 | | 110 F C C and 110 B 2 | | 111 F C C independent of their morphologies. There exist three kinds of interfaces in the EHEA, namely, (321) B2 ||(112) FCC , (01 1 ¯) B2 ||(33 2 ¯) FCC , and (23 1 ¯) B2 ||(552) FCC. The dominating (321) B2 ||(112) FCC interface and the secondary (01 1 ¯) B2 ||(33 2 ¯) FCC interface are both non-slip planes and atomistic-scale faceted, facilitating the nucleation and slip transmission of the dislocations. The formation mechanism of the preferred interfaces is revealed using the atomistic geometrical analysis according to the criteria of the low interfacial energy based on the coincidence-site lattice (CSL) theory. In particular, the ductility of the dual-phase alloy originates from the KS interface-induced slip continuity across interfaces, which provides a high slip-transfer geometric factor. Moreover, the strengthening effect can be attributed to the interface resistance for the dislocation transmission due to the mismatches of the moduli and lattice parameters at the interfaces. [ABSTRACT FROM AUTHOR]

Understanding the interface between strengthening precipitates and matrix in alloys, especially at the atomic level, is a critical issue for tailoring the precipitate strengthening to achieve desired mechanical properties. Using high-resolution scanning transmission electron microscopy, we here clarify the semi-coherent interfaces between the matrix and long-period stacking ordered (LPSO) phases, including 18R and 14H, in Mg–Zn–Y alloys. The LPSO/Mg interface features the unique configuration of the Shockley partial dislocations, which produces a near zero macroscopic strain because the net Burgers vectors equal zero. The 18R/Mg interface characterizes a dissociated structure that can be described as a narrow slab of 54R. There are two dislocation arrays accompanied to the 18R/54R and 54R/Mg interface, resulting a slight deviation (about 2.3°). The 14R/Mg interface exhibits the dislocation pairs associated with solute atoms. We further evaluate the stability and morphology of the corresponding interfaces based on elastic interaction, via calculating the mutual strong interactions between dislocation arrays, as well as that between the dislocations and solute atoms. The synchronized migration of interfacial dislocations and solute atoms, like move-drag behavior, dominates the lateral growth of LPSO phases in Mg alloys. [ABSTRACT FROM AUTHOR]

B 4 C particulate-reinforced 6061Al composite was fabricated by powder metallurgy method. The as-rolled composite possesses high tensile strength which is comparable to that of the peak-aged 6061Al alloy. More importantly, the microstructures and mechanical properties are thermally stable during long-term holding at elevated temperature (400 °C). The microstructual contributions to the strength of the composite were discussed. Transmission electron microscopy (TEM) analysis indicates that the in-situ formed reinforcement Mg(Al)B 2 , as products of the interfacial reactions between B 4 C and the aluminum matrix, show not only good resistance to thermal coarsening but also strong pinning effect to the grain boundaries in the alloy matrix. [ABSTRACT FROM AUTHOR]

Abstract High entropy alloys (HEAs) have presented potential applications in nuclear power plants owing to their novel atomic structure based high irradiation resistance. However, understanding of He-ion irradiation of HEAs is still lacking. In this work, we reveal He-ion irradiation resistance of HEA CrMnFeCoNi by comparison study with a pure Ni and a 304 stainless steel (304SS). It is found that the damage structure in the three materials can be characterized with He bubbles and stacking faults/stacking fault tetrahedrons ((SFs/SFTs), which show a similar depth distribution after He-ion irradiation at both RT and 450 °C. Although the He bubbles have a similar size about 2 nm after irradiation at RT, the He bubble sizes of the HEA, 304SS, and Ni increase to 4.0 ± 0.9, 5.3 ± 1.0 and 6.7 ± 1.0 nm after irradiation at 450 °C, respectively. Moreover, the density of SFs/SFTs displays in an order of Ni < 304SS < HEA at both RT and 450 °C. The He-ion irradiation at RT causes significant hardness enhancement for the three materials, however, compared to RT, after irradiation at 450 °C, the Ni presents softening, while the 304SS, especially the HEA, shows further hardening. Thus, the HEA CrMnFeCoNi possesses the smallest He bubble size, the densest SFs/SFTs, and the highest hardening, indicating the best structural stability, as well as the best He-ion irradiation resistance, which can be attributed to its low mobility of He atoms and point defects. [ABSTRACT FROM AUTHOR]

The toxic gases, such as CO and NO, are highly dangerous to human health and even cause the death of person and animals in a tiny amount. Therefore, it is very necessary to develop the toxic gas sensors that can instantly monitor these gases. In this work, we have used the first-principles calculations to investigate adsorption of gases on defective graphene nanosheets to seek a suitable material for CO sensing. Result indicates that the vancancy graphene can not selectivly sense CO from air, because O2in air would disturb the sensing signals of graphene for CO, while the nitrogen-doped graphene is an excellent candidate for selectivly sensing CO from air, because only CO can be chemisorbed on the pyridinic-like N-doped graphene accompanying with a large charge transfer, which can serve as a useful electronic signal for CO sensing. Even in the environment with NO, the N-doped graphene can also detect CO selectively. Therefore, the N-doped graphene is an excellent material for selectively sensing CO, which provides useful information for the design and fabrication of the CO sensors.

We have shown from both simulations and experiments that zwitterion functionalized carbon nanotubes (CNTs) can be used to construct highly efficient desalination membranes. Our simulations predicted that zwitterion functional groups at the ends of CNTs allow a high flux of water, while rejecting essentially all ions. We have synthesized zwitterion functionalized CNT/polyamide nanocomposite membranes with varying loadings of CNTs and assessed these membranes for water desalination. The CNTs within the polyamide layer were partially aligned through a high-vacuum filtration step during membrane synthesis. Addition of zwitterion functionalized CNTs into a polyamide membrane increased both the flux of water and the salt rejection ratio. The flux of water was found to increase by more than a factor of 4, from 6.8 to 28.7 GFD (gallons per square foot per day), as the fraction of CNTs was increased from 0 to 20 wt %. Importantly, the ion rejection ratio increased slightly from 97.6% to 98.6%. Thus, the nanotubes imparted an additional transport mechanism to the polyamide membrane, having higher flow rate and the same or slightly better selectivity. Simulations show that when two zwitterions are attached to each end of CNTs having diameters of about 15 Å, the ion rejection ratio is essentially 100%. In contrast, the rejection ratio for nonfunctionalized CNTs is about 0%, and roughly 20% for CNTs having five carboxylic acid groups per end. The increase in ion rejection for the zwitterion functionalized CNTs is due to a combination of steric hindrance from the functional groups partially blocking the tube ends and electrostatic repulsion between functional groups and ions, with steric effects dominating. Theoretical predictions indicate that an ideal CNT/polymer membrane having a loading of 20 wt % CNTs would have a maximum flux of about 20000 GFD at the conditions of our experiments.

Both the solid solution and precipitation are mainly strengthening mechanism for the magnesium-based alloys. A great number of alloying elements can be dissolved into the Mg matrix to form the solutes and precipitates. Moreover, the type of precipitates varies with different alloying elements and heat treatments, which makes it quite difficult to understand the formation mechanism of the precipitates in Mg-based alloys in depth. Thus, it is very hard to give a systematical regularity in precipitation process for the Mg-based alloys. This review is mainly focused on the formation and microstructural evolution of the precipitates, as a hot topic for the past few years, including Guinier-Preston Zones, quasicrystals and long-period stacking ordered phases formed in a number of Mg-TM-RE alloy systems, where TM = Al, Zn, Zr and RE = Y, Gd, Hd, Ce and La.

A porous coordination framework material, Zn4O(BDC)(BTB)4/3(labeled 1for simplification), has been prepared and applied to hydrogen storage. Its storage capacity has been measured, and the absolute and excess H2adsorption uptakes reach 6.23 and 5.43 wt % at 77 K and 20 bar, respectively. Moreover, a multiscale simulation method, which combines first-principles calculation and grand canonical Monte Carlo simulation, has been used to evaluate H2adsorption in this material. The simulation results successfully reproduce the experimentally determined hydrogen uptake in 1at T= 77 K and in the pressure range 0−20 bar. Furthermore, the simulation predicts that the hydrogen capacity in 1reaches 9.5 wt % at 77 K and 100 bar, which is among the highest reported in the literature to date. Clearly, this material is a promising adsorbent for hydrogen storage.

Machine learning techniques such as support vector regression (SVR) and artificial neural network (ANN) algorithms are employed to screen binary barium family (BamXn) compounds with low lattice thermal conductivity. To this aim, the electronic structures and thermoelectric (TE) properties of Ba2X6(X = S, Se, Te) are studied utilizing the first-principles density functional theory (DFT) together with the semiclassical Boltzmann transport theory (SBTT). The results indicate that Ba2Se6and Ba2Te6exhibit low lattice thermal conductivity (∼0.26 and 0.31 W m–1K–1) at room temperature. The electronic structure calculations show that three Ba2X6(X = S, Se, Te) compounds are indirect band gap semiconductors with gap values of 1.37, 0.84, and 0.92 eV, respectively. The TE calculations show that the maximum ZT value of Ba2Te6can be up to 3.51 at 800 K and 1.4 at 300 K. Our results indicate that all Ba2X6(X = S, Se, Te) host good TE performances covering wide temperature ranges and have potential applications. In addition, the developed methods in this work may help to further search other materials of high TE performances.