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Heteroatom-doped carbon nanotubes are considered as promising materials for supercapacitors because of their prominent contributions in terms of faradaic capacitance and electron donor capability.

There is keen interest in using Ti alloys as lightweight structural materials for aerospace and automotive industries. However, a long-standing problem for these materials is their poor oxidation resistance. Herein, we designed and fabricated a Ti5Si3 reinforced Ti-4(wt.%)Mo composite with two-scale network architecture by low energy milling and spark plasma sintering. It displays superior oxidation resistance at 800°C owing to the in-situ formation of a multi-component surface layer. This oxide layer has a dense grain size gradient structure that consists of an outer TiO2 layer and an inner SiO2-padding-TiO2 layer, which has remarkable oxidation resistance and thermal stability. Furthermore, it was revealed that the hitherto unknown interaction between Ti5Si3 reinforcement and nitrogen during oxidation would contribute to the formation of a TiN nano-twin interface layer, which accommodates the thermal mismatch strain between the oxide layer and matrix. This, along with high adhesion, confers excellent thermal cycling life with no cracking or spallation during long-term oxidation. In this regard, the secure operating temperature of this new composite can be increased to 800°C, which provides a design pathway for a new family of Ti matrix composites for high-temperature applications.

The preparation of alloyed bimetallic nanoparticles (BNPs) between immiscible elements is always a huge challenge due to the lack of thermodynamic driving forces. W–Cu is a typical immiscible binary system, and it is difficult to alloy them under conventional circumstances. Here, we used the bond energy model (BEM) to calculate the effect of size on the alloying ability of W–Cu systems. The prediction results show that reducing the synthesis size (the original size of W and Cu) to less than 10 nm can obtain alloyed W–Cu BNPs. Moreover, we prepared alloyed W50Cu50 BNPs with a face-centered-cubic (FCC) crystalline structure via the nano in situ composite method. Energy-dispersive X-ray spectroscopy (EDS) coupled with scan transmission electron microscopy (STEM) confirmed that W and Cu are well mixed in a single-phase particle, instead of a phase segregation into a core-shell or other heterostructures. The present results suggest that the nanoscale size effect can overcome the immiscibility in immiscible binary systems. In the meantime, this work provided a high-yield and universal method for preparing alloyed BNPs between immiscible elements.

Titanium alloys are desirable for applications in advanced hypersonic aircraft engines and gas turbines, but currently few materials can satisfy the associated high temperature oxidation requirements. Herein, we designed and fabricated a Ti5Si3 reinforced Ti-4Mo composite with a two-scale network architecture by low energy milling and spark plasma sintering. It displays superior oxidation resistance at 800°C owing to the in-situ formation of a multi-component surface layer. This oxide layer has been revealed to have a dense grain size gradient structure that consists of an outer TiO2 oxide layer and an inner TiO2 and SiO2 mixed oxide layer with a core-shell structure, which has remarkable oxidation resistance and thermal stability. Furthermore, it was revealed that the hitherto unknown interaction between Ti5Si3 reinforcements and nitrogen during oxidation would contribute to the formation of a TiN nano-twin interface layer, which accommodates the thermal mismatch strain between oxide layer and matrix. This along with high adhesion confers excellent thermal cycling life with no cracking or spallation during long term oxidation. In this regard, the secure operating temperature can be increased to 800°C, which can provide a design pathway for a new family of titanium matrix composites for high-temperature applications.

Fine-grained tungsten was prepared by sintering nano‑tungsten powder and its properties was further improved by warm rolling in the paper. And the microstructure and texture evolution of fine-grained tungsten under different rolling reduction was mainly investigated. Detailed microstructure characterizations under different rolling reduction stages showed a large number of sub-grain structures appeared in the fine-grained rolling tungsten grains, which increases the grain boundary area. Quantitative texture analysis showed that the rolled fine-grained tungsten had a typical BCC texture, the overall texture strength was enhanced after 50% RR and the texture intensity of grains larger than the average grain size was stronger than that of the whole grains, especially in the center of {111} pole figure. Warm rolling of fine-grained tungsten strongly affects the mechanical properties of tungsten, such insights in warm-rolled tungsten are valuable for an understanding of their performance as potential plasma-facing materials in future fusion reactors.