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The mechanical reliability of metallic components is vital for the stable operation of electrical equipment, especially for those used in ultra-high voltage transmission and electromagnetic launching, where metallic materials inevitably suffer from high-density current and strong magnetic field. However, little has been known about the mechanical behavior of metals under the electric-magnetic coupling stimuli. Here, by performing quantitative electromechanical tests under the built-in magnetic field inside transmission electron microscope, we found that copper, one of most commonly used conductive metals, can be significantly softened by the coupled electrical-magnetic stimuli, manifested as notable yield strength drop by five-times and obvious creep deformation at room temperature. A plausible mechanism behind the unusual softening, local-Lorentz-force-assisted dislocations depinning, has been proposed. Our results shed new light on understanding the deformation-induced failure of metals served in electromagnetic environments, and also inspire a new mechanical processing way for reshaping metals at much lower loads and temperatures. [Display omitted] [ABSTRACT FROM AUTHOR]

Chestnut-like SnO 2 and SnO 2 /C nanocomposites with hierarchical structures are synthesized by hydrothermally oxidizing Sn nanoparticles in glucose solution. Structural characterizations using SEM and TEM reveal that the SnO 2 nanoparticles are composed of numerous, randomly arranged SnO 2 nanosheets with hollow cores. Owing to the short electron and ion diffusion distances and transformation strain accommodation mechanism of this structure the new SnO 2 /C nanocomposites exhibit enhanced lithium ion storage properties with a capacity of ~930 mAh g −1 and capacity retention of about 96% after 100 cycles at 0.1 C. An in situ TEM study of the electrochemically driven lithiation/delithiation of SnO 2 /C nanocomposites reveals that their enhanced cycling stability is mainly facilitated by the limited volume expansion and excellent mechanical robustness of the hollow chestnuts. [ABSTRACT FROM AUTHOR]

Ti–Al–C–N protective coatings were prepared using laser cladding on the TC4 in this work. MAX phase is generated in situ in the coating. Moreover, as an in-situ autogenous reinforcing phase, MAX phase has good compatibility with the substrate and good bonding force, which is conducive to the full realization of the cladding performance. The results show that the amount of MAX phase increased with the proportion of ceramic phase in the composition design. Among them, the best coating performance is achieved when the component ratio is TiAl: TiN: TiC = 1:1:1. The coating shows the highest hardness of 712–950 HV, which was about twice the hardness of the substrate. It also shows the best resistance to fretting wear at both room temperature and 400 °C. The analysis of the wear mechanism reveals that twins are formed in C1 coatings during fretting wear at both room temperature and 400 °C. The twins not only can rapidly relax the local stress concentration and maintain the plasticity of the material, but also can promote the continuation of slip, and play an obvious strengthening effect without causing serious stress concentration. This work can provide the theoretical basis and data support for the functional-structural integration of protection design of components under actual working conditions. [ABSTRACT FROM AUTHOR]

The dislocation-mediated coupling mechanism between the microstructural defects and Te inclusions in CdZnTe crystal have been investigated through the defect-selective etching and cathodoluminescence (CL). The enrichment of well-arranged dislocation-related defects was found around the Te inclusions. A dislocation-mediated defects interaction model was proposed and native deep-level defects were considered to be associated with induced dislocation motions, showing as a dark CL contrast. The spatial arrangement of the microstructural defects were confined to a stellated octahedron. [ABSTRACT FROM AUTHOR]