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The dynamic mechanical behaviors of 7B52 laminated aluminum alloy under different impact deformation conditions were investigated using split Hopkinson pressure bar, optical microscopy, electron backscatter diffraction and transmission electron microscopy. The results show that the 7B52 laminated aluminum alloy displays positive strain rate sensitivity and negative temperature sensitivity. Cracks are formed firstly at the interface between the 7A62 hard layer and the 7A01 middle layer under a low strain rate of 2200 s−1. When the strain rate increases to 3500 s−1, the deformation shear band is firstly formed in the 7A52 soft layer. The deformation shear band transformed to the transition shear band with the increase of strain rate, and then crack initiated. Adiabatic shear bands and cracks are formed in both of the hard and soft layers when samples impacted at a high strain rate (5500 s−1). Most of the cracks and adiabatic shear bands are unable to penetrate the middle layer due to the good toughness of the 7A01 alloy. The deformation of each layer of 7B52 laminated aluminum alloy becomes more uniform when the temperature increases, which was attributed to the reduction of difference in strength among the three layers and the coordinating effect of grain boundary on deformation.

Due to the low density and high fatigue strength, Al-Cu-Mg alloy has become an attractive material for aerospace and navigation applications. However, the relatively high residual stress and low micro-yield strength after the fabrication process restrict its further application in the field of inertial instruments. The objective of this work is to investigate the effect of Ni plating on the residual stress and micro-yield strength in an Al-Cu-Mg alloy under different diffusion treatments. Compared with properties of the alloy without diffusion treatment, the micro-yield strength of the alloy after diffusion treatment increases 9.5%, and the corresponding residual stress decreases > 70%. This can be attributed to the increase of diffusion layer thickness and release of elastic energy.

An experimental set-up for the fatigue testing of Al alloy in dusty environments was developed and the effect of a graphite dust environment on the fatigue crack propagation behaviour of 2524-T3 Al alloy was investigated. The fatigue crack propagation rates (FCGRs) are higher for the sample in graphite dust especially at low ΔK-levels and tends to be similar to those in air with increasing ΔK. This acceleration effect of graphite dust is due to the lubrication of the absorbed graphite particles on the mating fracture surfaces which decreases the extent of crack closure and promotes microcrack growth.

The recycled aggregate obtained by simple crushing and screening of waste concrete has a rough surface and many protruding edges and corners, and most of the aggregate surface is attached with old mortar, when directly used as aggregate in concrete, the water demand is large, the concrete strength and elastic modulus are low, and the durability is poor. Therefore, proper treatment of recycled aggregate is required.This article summarizes the research status of the pretreatment methods of mechanical strengthening, heating grinding, solution impregnation, cement slurry impregnation, carbonization treatment, nano-modification, microbial modification and water cleaning etc., and simply analyzes the advantages and disadvantages of various treatment methods, which provide a reference for the research of recycled aggregate processing methods.

An experimental method of evaluating the fatigue behavior of alloys in different particle environments was designed, and the effects of four kinds of particles (i.e., graphite, CaO, Al2O3, and MnO2) on the crack propagating behavior of 7N01-T6 behaviour alloys were investigated. The results show that the particles deposited on the crack surface exert significant influence on the fatigue crack propagation behavior thereof. This influence strongly depends on the elastic moduli of the particles (Ep). As Ep is less than that of aluminium alloy (EAl), the particle accelerates the fatigue-crack-growth rate (FCGR) in the alloys due to the lubrication of the particles on the mating fracture surfaces. When the difference between Ep and EAl is small, the particle effect on the FCGRs of the alloys is small due to the counteraction between the decrease in friction and the promotion on the crack closure of mating fracture surfaces. When Ep is greater than EAl, the particles slow down the FCGRs of the alloys on account of significant crack closure effect. As Ep is much greater than EAl, the particles increase the FCGRs because of the increasing stress concentration at the crack tip.

The effects of service environment and pre-deformation on the fatigue behaviour of 2524 alloy were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fatigue tests. The results indicate that the fatigue crack-growth rate (FCGR) of the alloy in an aqueous environment increases with temperature ranging from 0 to 90 °C. At the same stress intensity factor range (ΔK), the FCGR of the alloy in an argon environment is the smallest, followed by that in air, and a 3.5% NaCl fog environment, while that in an exfoliation corrosion (EXCO) solution is the largest. A pre-deformation of 2% can significantly enhance the fatigue crack propagation resistance of this alloy in argon, air, and 3.5% NaCl fog environments, while 5% pre-deformation weakens the fatigue crack propagation resistance of the alloy accordingly. The pre-deformation effect on the FCGR of alloy in the EXCO solution environment is limited.

The anti-phase boundaries (APBs) in the T (Al20Cu2Mn3) phase and the interfaces of the T phase with an Al matrix were observed. The effects of pre-deformation on the precipitation behavior of T phase and hardening behavior of alloy were investigated by hardness measurement, mechanical tensile test, transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Results show that two kinds of APBs exist in the T phase, i.e. {101}T and {301}T-type APBs. The first is commonly observed, while the latter is newly found and only coexists with the first to form a zig-zag shaped APB. Whatever its orientation relationships (ORs) with Al matrix and cross-section (CS) shape, the T phase always retains its interfaces constituted by {200}T, {101}T and {301}T planes. Pre-deformation increases the APBs in T phase and intensifies the irregularity of the CS shape of a T phase. Besides, it also promotes the nucleation and refines the size of the T phase during precipitation which enhances the mechanical properties of the alloy.

Despite progress, the combination therapy of a nanoscale delivery system and its loaded drug to increase the efficiency of anticancer treatment still remains a challenge. In this study, taking advantage of ascorbic acid with anticancer activity, complex nanovehicles were designed and constructed by co-assembly of the amphiphilic block polymers poly(ascorbyl acrylate)-block-poly(lactic acid) (PAA-b-PLA) and maleimide-decorating poly(ethylene glycol)-block-poly(lactic acid) (Mal-PEG-b-PLA) in aqueous solution. The combination of the nanoparticles' large surface and structural repeating characteristics of PAA led to an exponential increase in the ascorbyl content on the nanoparticle surface, which endowed the nanovehicles themselves with desired anticancer activity. In vitro cytotoxicity assays against normal cell line NIH3T3 and breast cancer cell line MCF-7 demonstrated that PAA-b-PLA/Mal-PEG-b-PLA complex nanoparticles exhibited benign biocompatibility against normal cells and prominent cancer inhibition ability. Paclitaxel (PTX)-loaded complex nanoparticles against MCF-7 were further investigated by MTS assay and flow cytometry. As a result, a synergistic effect of the complex nanoparticles and the loaded PTX in inducing cancer cell apoptosis was apparently noted. The newly developed PAA-b-PLA/Mal-PEG-b-PLA complex nanoparticles not only served as an effective and safe vector to deliver the therapeutic agents to the targeted site, but more importantly, they could also combine with the loaded therapeutic agents to achieve a synergistic effect for improving tumor inhibition efficiency.

To improve the service reliability of components prepared by TiC-reinforced steel matrix composite material, tempering treatment was carried out to tailor the microstructure and properties of the composite. The aim of this study was to investigate the microstructure, properties, and dimensional stability of a TiC-reinforced steel matrix composite during tempering and to identify the underlying stabilizing mechanisms. We observed that the metastable retained austenite transformed into martensite and that residual stress released during tempering. The microstructure and properties of the composite reached an optimal state for a tempering time of 10 h. Furthermore, the relative dimensional change, Vickers hardness, thermal strain, and saturation magnetization of the composite were 0.0219%, 960.8 HV, 3.16 × 10−4, and 109.7 emu/g, respectively. Various stabilizing mechanisms, including retained austenite-martensite transformation and residual stress release, were observed during tempering, effectively improving the dimensional stability of TiC-reinforced steel matrix composites.

We report on the existence of coherently coupled black-white vector solitons in a net anomalous cavity fiber ring laser. The experimental observation and simulation results provide solid support for the existence evidence.