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It is still challenging to synchronously improve mechanical properties and corrosion resistance through one strategy during developing Mg alloys. Introducing high-density precipitates is an effective and popular approach to strengthen Mg alloys, while these precipitates generally degrade the corrosion resistance. In this paper, the nanoprecipitates are developed in Mg-13.4Gd-2.2Ag-0.4Zr wt.% cast alloy through the solution and aging treatment for evading this dilemma. Compared with its as-cast counterpart, the peak-aged alloy with high-density nanoprecipitates exhibits enhanced strength, comparable ductility, and improved corrosion resistance. The nanoprecipitates in the peak-aged alloy are composed of β nanoparticles at grain boundaries, and intragranular γ′′ and β′ nanoplates. These nanoprecipitates are contributed to the improved strength through the Orowan mechanism. The β nanoparticles induce weak galvanic corrosion, and the γ′′ nanoplates have not induced visible galvanic corrosion, thus contributing to the enhanced corrosion resistance of the peak-aged alloy. This result suggests that developing nanoprecipitate is a feasible route to collaboratively optimize the mechanical and corrosion properties of the Mg alloys.

Selective laser melting (SLM) is one of the common methods of additive manufacturing and herein, ultrasonic severe surface rolling (USSR) is applied to enhance the corrosion resistance of SLM 316L stainless steel (SS) in the 3.5% NaCl solution. USSR produces a thick (∼1 mm) gradient surface layer with a nanostructured, chemically homogeneous, and high-quality surface but a small amount of martensite. The USSR processed 316L SS exhibits significant enhancement in the corrosion resistance compared to the SLM one, as manifested by the greatly improved pitting potential, decreased passive current density, and reduced corrosion current density. The superior corrosion properties stem from the unique gradient structure with a high density of grain boundaries and chemically homogeneous and high-quality surface facilitating the formation of a thicker and more protective passive film that contains larger contents of oxides and hydroxides of Fe and Cr in spite of almost the same total Cr concentration. In addition to the high strength and ductility, the unique gradient structure endows the SLM 316L SS with superior corrosion resistance and long service lifetime in the marine environment, boding well for application to marine equipment and engineering.

Armillaria mellea polysaccharides (AMPs) were obtained by ultrasonic assisted extraction (U), enzyme assisted extraction (E) and ultrasonic-enzyme assisted extraction (UE), respectively. The yield of UE-AMPs (6.32 ± 0.14%) was 1.64 times higher than that of U-AMPs (3.86 ± 0.11%) and 1.21 times higher than that of E-AMPs (5.21 ± 0.09%); meanwhile, the highest total sugar content and the lowest protein content were found in UE-AMPs. AMPs obtained from the three extraction methods had the same monosaccharide composition but in different proportions, allowing UE-AMPs to have the most potent antioxidant activity. The antidiabetic activity of UE-AMPs was investigated in streptozotocin (STZ)-induced diabetic mice. UE-AMPs, when given by gavage, greatly prevented weight loss, increased water intake, and considerably decreased blood glucose levels in diabetic mice, which were dose-dependent (P

A homogeneously ultrafine-grained (UFG) Cu-38 Zn alloy with an average grain size of 0.64 μm is successfully fabricated by equal channel angular processing (ECAP), which exhibits a significantly enhanced strength-ductility synergy. The strength enhancement can be attributed to grain refinement and dislocation strengthening. After annealing the ECAP processed alloy at 300 °C for 30 min, a further enhanced strength with almost unchanged ductility was achieved. This unusual annealing strengthens is associated with the solute/impurity segregation and precipitations inside the grains.

In this study, the stable system of bilayer emulsion was fabricated by ultrasonic emulsification. The effect of chitosan (CS) addition (0.05 %-0.4 %, w/v) at pH 5.0 on the stability of rice bran protein hydrolysate-ferulic acid (RBPH-FA) monolayer emulsion was investigated. It was found that the addition of CS (0.3 %) could form a stable bilayer emulsion. The droplet size was 3.38 μm and the absolute ζ-potential value was 31.52 mV. The bilayer emulsion had better storage stability, oxidation stability and environmental stabilities than the monolayer emulsion. The results of in vitro simulations revealed the bilayer emulsion was able to deliver the β-carotene to the small intestine digestive stage stably and the bioaccessibility was increased from 22.34 % to 61.36 % compared with the monolayer emulsion. The research confirmed that the bilayer emulsion prepared by ultrasonic emulsification can be used for the delivery of hydrophobic functional component β-carotene.

In this article, scanning electron microscopy, energy dispersive spectroscopy, and transmission electron microscopy were used to characterize the precipitation behaviour of the Cu-rich phase in Al-free and 1Al Cu-bearing ferrite stainless steels; and further, the effects of Al addition on the precipitation and coarsening of the Cu-rich phase and its mechanism were analysed. The results show that Al increases the nucleation rate of the Cu-rich phase, and refines Cu-rich nanoprecipitates after ageing for 1 min. The Cu-rich phase with four crystal structures-BCC, 9R, twin FCC, and non-twin FCC were found in the Al-free sample during ageing. However, only Cu-rich phase with BCC and BCT structures were observed after Al addition. There are high-density edge dislocations in Al-containing Cu-rich nanoprecipitates. These dislocations can be used as a diffusion channel for solute atoms, increasing the coarsening rate of the Cu-rich phase. However, with the extension of the ageing time, dislocations in the Cu-rich phase will be annihilated owing to the thermal activation and the decrease of the Al concentration in the Cu-rich phase, which will lead to a decrease in the dislocation density in Al-containing Cu-rich phase. Finally, the promotion effect of Al on the coarsening of the Cu-rich phase is weakened.

It is challenging to develop Mg alloys with high strength-ductility synergy and isotropic mechanical properties. An industrial-scale ultrafine-grained (UFG) Mg-10.6Gd-2Ag wt. % alloy with excellent strength-ductility synergy and near-isotropic mechanical behavior was made by an industrial-scale rotary die equal channel angular pressing (RD-ECAP). The microstructure of the UFG alloy involves the primarily submicron α-Mg grains with an average grain size of 760.5 nm and the high-density submicron β phase (Mg5Gd) precipitates (267.8 nm). Room temperature tensile tests results reveal that the UFG alloy exhibits an over three times tensile yield strength, near two times ultimate tensile strength, and more than one and a half times elongation along three orthogonal test directions than the as-cast Mg alloy. The improvement of strength is linked to the effect of the grain boundary strengthening as well as the precipitation strengthening. The enhanced ductility is ascribed to the ultrafine grains with low dislocation density, which provide a degree of dislocation storage capacity and facilitates multiple potential deformation modes. The near-isotropic mechanical behavior stems from the weak texture and multiple deformation modes.

Developing magnesium alloys with both high corrosion resistance and superior mechanical properties is a long-standing challenge for the lightweight metal community. Herein, processing route combining equal-channel angular pressing (ECAP) and water annealing to achieve simultaneous improvements on both anti-corrosion and mechanical performances of a Mg-2Zn-Mn-Ca-Ce alloy is proposed. The cast alloy was ECAP-processed at 573 k for 12 passes to obtain ultra-fine grains (UFG), followed by water annealing in the autoclave under 160 °C for 3 h. The treated sample exhibits significantly improved corrosion resistance, presenting less corrosion current density and hydrogen evolution rate in the Hanks' solution. The doubled yield/ultimate strength and elongation, as well as the better-maintained mechanical integrity after corrosion, were achieved simultaneously. The profuse dislocations and grain boundaries in the UFG substrate offer intensive hydrothermal-reaction driving force, favoring the formation of a thicker and more compact Mg(OH)2 coating layer. Such a protective coating layer together with the annealed substrate with fewer crystal defects effectively retards the corrosion degradation and preserves the mechanical integrity afterwards. Meanwhile, the modified heterogeneous substrate microstructure results in the observed superior strength-ductility synergy. The proposed processing route and the resulted comprehensive properties should be applicable to other magnesium alloys as well. Keywords: Magnesium alloy, High strength and corrosion resistance, Materials processing, Heterogeneous microstructure