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[Display omitted] • Double-peak age strengthening phenomenon was first found in the Cu–Be–Ni–Co alloys. • The coherency strengthening of tiny nanoprecipitates contributes significantly to the appearance of first peak. • The light-mass Be atoms were directly made out by using the iDPC-STEM technology. Unconventional double-peak age strengthening phenomenon has occasionally been observed in some alloys, yet the underlying mechanism responsible for this phenomenon are still unclear. Here, we for the first time report the double-peak age strengthening phenomenon in the Cu–Be–Ni–Co alloys and try to unveil the underlying mechanism. Both the theoretical and experimental analyses demonstrate that the strong coherency strengthening effect of tiny nanoprecipitates (<1 nm) contributes significantly to the appearance of first peak, whereas the order-to-Orowan strengthening transformation accounts for the appearance of second peak. Moreover, the precipitate evolution processes of the alloys are identified as Guinier–Preston (GP) zones → γ′′→ γ′ and the light-mass Be atoms in the γ′ phase are directly made out by using integrated differential phase-contrast scanning transmission electron microscopy (iDPC-STEM) technology. Our work may provide new insights into the coherency strengthening effects and demonstrates a powerful strategy for designing high performance via double-peak behavior. [ABSTRACT FROM AUTHOR]

The bi-layer composite ceramic armors are widely used in the protection field, and its design method is keep changing since the Florence model has been found. In this study, an analytical design method of bi-layer was proposed and examined with a new ceramic protection efficiency definition. With this definition, the protection efficiency of composite ceramic armor can be divided into two independent parts: the protection efficiency of ceramic and the protection efficiency of backing plate. By using this analytical design method, the design of the bi-layer ceramic armor can be more efficiency and the material of armor can be selected more accurately. [Display omitted] • A design method for bi-layer ceramic armors is established. • Proposed method was verified using numerical simulation and bullet impact experiments. • Analytical solution was in predicting total armor protection efficiency per unit area density. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new method was proposed for preparing modified clays to control harmful algae blooms: single source with series modifications. • Kaolin that was modified by the new method could remove over 85% of Prorocentrum donghaiense cells. • Calcination, acid–alkali treatment, and the supplementation of raw kaolin during aging were indispensable processing steps in the new method. • A schematic mechanism of kaolin modification by the new method to obtain modified clay with high algal cell removal efficiency was illustrated. Modified clay (MC) is an effective and eco-friendly material that is widely used for controlling harmful algae blooms (HABs). In this study, a new method—single source with series modifications (SSSM)—was optimized for preparing a high-quality MC, and aluminum-rich clay (kaolin) was activated with a multistep treatment that included calcination (Cal), acid etching with alkali neutralization (Al–An), and raw clay supplementation and aging (RSA). The results showed that the removal efficiency of Prorocentrum donghaiense by the SSSM–MC exceeded 85%; Cal, Al–An, and RSA were indispensable processing steps for preparing the best MC with the SSSM method. The changes occurring in the mineral structure and chemical composition of kaolin treated by the different steps were characterized by FT-IR, XRD, 27Al-NMR and Al-Ferron. Surface dehydroxylation and disruption of the kaolin lattice after calcination significantly changed the aluminum structure from AlVI to AlV and AlIV. The relatively reactive AlV was readily released from the kaolin lattice with acid etching, and it subsequently reacted with external OH– to generate different polyhydroxyaluminum species because alkali was added during the Al–An step. The acidity of the above complex was further decreased by RSA, greatly increasing the yield of SSSM–MC while assuring the quality. [ABSTRACT FROM AUTHOR]

Confined silicon carbide (SiC) plates covered with aluminium alloy, mild steel, and copper alloy materials of different elastic impedances were subjected to normal impact by blunt tungsten-heavy-alloy projectile of 16 mm diameter and 40 mm length, at a nominal striking velocity of 1.25 km/s. Failure analysis of the armour modules and penetration weight calculated by the measured residual penetration were applied to characterize ballistic performance of the ceramic armour modules. A simulation calculation was employed to investigate the inner impact process and the results corresponded well with the experimental ones. The damage initiation and propagation in ceramic, and the stress field distribution in the projectile were presented and analysed. The results showed that the cover plate can effectively reduce the damage of the target due to the extension of a dwell period compared with a 'no cover' structure. Low- elastic impedance material covers promote the impact stress distribution in ceramic leading to great improvement in ceramic ballistic performance. Moreover, the effect of cover material properties and energy dissipation at different impact periods was discussed. Unlabelled Image • Targets with multiple covers respond differently and optimal for aluminium cover. • The benefits of cover plate are elaborated by promoted flow and distributed damage. • Materials impedance properties are introduced and correlated to ballistic resistance. • Hard steel cover can prolong dwell time by enhancing the shear strength of ceramic. [ABSTRACT FROM AUTHOR]

Abstract Two novel diamond lattice structures (Dfcc and Dhex) and the typical face-centered cubic (FCC) and body-centered cubic (BCC) lattice structures are manufactured by selective laser melting (SLM), and the effects of cell topology and relative density on the dynamic behavior of these structures are studied through a combination of experimental tests and numerical simulation. It is observed that in Dfcc and Dhex, failure initiates at the connection points between rods in the middle of the structure, causing a sudden drop of the measured stress value. However in FCC and BCC, failure initiates in the face-truss junction. Generally, the FCC and BCC are dominated by stretching and bending of the rods respectively, whereas the Dfcc and Dhex are a mixture of the two deformation modes. The results show that the mechanical properties of the lattice structures with different relative density can be described by a power law function. Moreover, for the lattice structures with the same rod diameter of 0.8 mm, FCC out-performs other structures in terms of specific strength, specific modulus and energy absorption. This gives evidence that lattice structures with the stretching-dominated deformation mode are more likely to exhibit better mechanical properties under dynamic loading. Graphical abstract Unlabelled Image Highlights • Two novel diamond lattice structures (Dfcc and Dhex) and the typical FCC and BCC lattice structures were designed. • A numerical simulation model has been developed, and was consistent well with the experimental results. • Using a power law function to relate different mechanical properties to rod diameter or relative density for each lattice type. • Stretching-dominated structures often exhibit better dynamic mechanical properties than bending-dominated structures. [ABSTRACT FROM AUTHOR]