Interface engineering has been demonstrated to be an effective strategy for enhancing the thermoelectric (TE) performance of materials. However, a very typical interface in semiconductors, that is, the PN junction (PNJ), is scarcely adopted by the thermoelectrical community because of the coexistence of holes and electrons. Interestingly, our explorative results provide a definitively positive case that appropriate PNJs are able to enhance the TE performance of p-type SbTe-based alloys. Specifically, owing to the formation of the charge-depletion layer and built-in electric field, the carrier concentration and transport can be optimized and thus the power factor is improved and the electronic thermal conductivity is decreased. Meanwhile, PNJs provide scattering centers for phonons, leading to a reduced lattice thermal conductivity. Consequently, the p-type (BiTe)-(SbTe) composites comprising PNJs achieve a ∼131% improvement of the ZT value compared with the pure SbTe. The increased ZT demonstrates the feasibility of improving the TE properties by introducing PNJs, which will open a new and effective avenue for designing TE alloys with high performance.

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A method of continuous casting is used and the research investigates microstructure and mechanical properties under different drawing velocity (R, mm/min). The results show that microstructure and composition measurement of different zones are uniform. The smallest grain size is 25.93 mm and formability is good with 0.5R. Compressive strength is higher with 0.5R and maximum value is 1697MPa. Fracture toughness with 0.5R improves about 35.7% which is 21.7MPaÁm1/2. The fracture morphology is trans-lamellar fracture and interface de-lamination. The method is a feasible way to continuously cast the TiAl-Nb alloys. The R is an important parameter to add high-melting-point element, which affects solidified temperature interval of solidification front and electromagnetic stirring.1700058 (1 of 7)

The recently proposed structural interface model is a realistic model of thick interfaces, but the bars of the structure are assumed iso-stiffness. In the present work, the structural interface consisting of pairs of bars with different stiffness is developed. Based on the neutral inclusion concept and elastic mechanics, the stiffness of bars of the structural interface is studied. It is found that all the bars have the same stiffness in a special loading condition of equal-biaxial tension. The finite element simulations for glass fiber-reinforced epoxy composite reveal that the fiber does not alter the prescribed stress due to the presence of the structural interface. Compared with the iso-stiffness-bar interface, the developed structure interface is more suitable for characterizing a multi-component interface and more flexible to be designed.

Cord-rubber composites are usually subjected to cyclic deformation for the tire applications. Due to the hysteretic nature of the rubber, heat generation in the rubber component under dynamic cyclic loading often causes a rise in temperature, which can deteriorate the physical properties of the composites. Therefore, better understanding of the cord-rubber composites under thermal aging conditions is of great importance for the lifetime prediction. In the present work, the effective modulus of polyester cord- and steel cord-rubber composites at different aging conditions was studied by means of the mechanics of composite materials and the Arrhenius relationship based on the properties of components. It is found that the Halpin-Tsai relation with introducing the effect of thermal aging is also valid for the aged cord-rubber composites.