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The key to restrict the engineering application of high-strength B4C/Al composites is corrosion, and adding trace alloying elements is an effective measure to improve corrosion resistance. In this work, the B4C/7075 and B4C/7075-0.15Sc-0.35Zr composite containing trace Sc and Zr elements were prepared by pressure infiltration. The influence of combined addition of Sc and Zr on microstructure, mechanical properties and corrosion behavior of B4C/7075 composites was investigated by using scanning electron microscopy, transmission electron microscopy, bending performance testing, tensile performance testing, neutral salt spray testing and electrochemical testing. Results showed that adding Sc and Zr elements to B4C/7075 composites, the higher bending strength and tensile strength values were obtained in B4C/7075-0.15Sc-0.35Zr. In addition, the corrosion rate and the corrosion current(Jcorr) decreased, indicating that the corrosion resistance of B4C/Al composite increased, which might be caused by that the grain boundary precipitates in the composite material were small and discontinuous after adding Sc and Zr elements, and the precipitate free zone(PFZ) disappeared.

The Split Hopkinson pressure bar (SHPB) is widely used for characterizing the mechanical behavior of materials at high strain rates. One of the most challenging factors is achieving constant strain rate (CSR) loading of the specimen at a certain strain rate. Obtaining the effective incident pulse based on the experimental material for achieving CSR loading remains unresolved. This research focuses on obtaining the proper incident pulse for achieving constant strain rate loading using the pulse-shaping technique. A parameterized objective incident model in terms of the strain rate and quasi-static (or dynamic stress–strain) behavior of the material is established utilizing the three-wave method. Experimental pulses that closely resemble the desired objective pulses can be generated by adjusting parameters such as the geometry of the shaper, the shaper material, striker velocities, and the length of the striker according to the pulse-shaping model. The model is applied to the design of the incident pulse for B4CP/2024Al composite material, and the dynamic stress–strain curves at different strain rates are obtained under CSRs. This model provides effective guidance for selecting an appropriate shaper and achieving CSR loading in SHPB tests. [ABSTRACT FROM AUTHOR]

Aluminum matrix composites (AMMCs) have demonstrated substantial potential in the realm of armor protection due to their favorable properties, including low density, high specific stiffness, and high specific strength. These composites are widely employed as structural components and frequently encounter high strain rate loading conditions, including explosions and penetrations during service. And it is crucial to note that under dynamic conditions, these composites exhibit distinct mechanical properties and failure mechanisms compared to static conditions. Therefore, a thorough investigation into the dynamic mechanical behavior of aluminum matrix composites and precise constitutive equations are imperative to advance their application in armor protection. This review aims to explore the mechanical properties, strengthening the mechanism and deformation damage mechanism of AMMCs under high strain rate. To facilitate a comprehensive understanding, various constitutive equations are explored, including phenomenological constitutive equations, those with physical significance, and those based on artificial neural networks. This article provides a critical review of the reported work in this field, aiming to analyze the main challenges and future development directions of aluminum matrix composites in the field of protection. [ABSTRACT FROM AUTHOR]

In this study, Al-B4C/Al laminated composites with high interlayer bonding strength were fabricated by integrated hot-pressed sintering accompanied with hot rolling. The mechanical properties and interface behavior of the Al-B4C/Al laminated composites were investigated under quasi-static and impact loading. The results show that the Al-B4C/Al laminated composites obtain a high interface bonding strength, because no interlayer delamination occurs even after fractures under quasi-static and impact loads. The Al-B4C/Al laminated composites exhibit a better comprehensive mechanical performance, and the fracture can be delayed due to the high bonding strength interface. Moreover, laminated composites can absorb more impact energy than the monolithic material under impact loading due to the stress transition and relaxation. [ABSTRACT FROM AUTHOR]

Ceramic panel collapse will easily lead to the failure of traditional targets. One strategy to solve this problem is to use separate ceramic units as armor panels. Based on this idea, we propose an aluminum matrix composite using pressure infiltration, containing an array of ceramic balls, the reinforcement of which consists of centimeter-scale SiC balls and micron-scale B4C particles. Three different array layouts were designed and fabricated: compact balls in the front panel (F-C), non-compact balls in the front panel (F-NC), and compact balls inside the target (I-C). The penetration resistance properties were tested using a 12.7 mm armor-piercing incendiary (API). The results show that there are no significant internal defects, and the ceramic balls are well-bonded with the matrix composite. The F-NC structure behaves the best penetration resistance with minimal overall damage; the I-C structure has a large area of spalling and the most serious damage. Finite element simulation reveals that the ceramic balls play a major role in projectile erosion; in the non-compact structure, the composite materials between the ceramic balls can effectively disperse the stress, thereby avoiding the damage caused by direct contact between ceramic balls and improving the efficiency of ceramic ball erosion projectiles. Furthermore, it is essential to have a certain thickness of supporting materials to prevent spalling failure caused by stress wave transmission during penetration. This multi-scale composite exhibits excellent ballistic performance, providing valuable insights for developing anti-penetration composite armor in future applications. [ABSTRACT FROM AUTHOR]

A simple and convenient method was developed for the preparation of a large number of high-purity cotton-like SiC@SiO2 nanowires by thermal evaporation without any catalyst. The Si particles with loose and discontinuous SiO2 coating (marked as Si@SiO2) were prepared by wet oxidation process as the source of silicon, and the high-purity graphite sheets were used as carbon sources. The large-scale of high purity SiC@SiO2 nanowires, which were over 100 μm in length and about 100 nm in diameter, were synthesized by the form of layers assembly of the graphite substrate according to the distribution of gas. The SiC@SiO2 nanowires have high crystallinity with flat and smooth surfaces. The synthesized SiC@SiO2 nanowires include single crystal 3C structures and 3C structures with defects along [111] direction. The distribution of the gas concentration in the reaction vessel and the growth mechanism of the SiC@SiO2 nanowires were studied. Furthermore, the SiC@SiO2 nanowires showed good blue-green photoluminescence (PL) property, which has been expected to make positive progress in the optoelectronic field. [ABSTRACT FROM AUTHOR]