Thermoelectric properties of transition metal (Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, or W)-doped PbSe were studied. Peak ZT similar to 1.1, similar to 1.15, and similar to 1.2 at about 873 K has been achieved in Ti0.015Pb0.985Se, Zr0.005Pb0.995Se, and Nb0.01Pb0.99Se, respectively, with increased room temperature Hall carrier concentration to similar to 10(19)-10(20)cm(-3). However, the lower temperature ZT(<600 K) is not favorable compared with other transition metal (V, Cr, Mo, or W)-doped PbSe with lower doping concentration. Higher room temperature ZT contributes to the higher average ZT despite lower peak ZT. First-principles calculation found resonant states created in n-type PbSe doped by Ti, V, Zr, Nb, Mo, Hf, Ta, or W similar to Cr-doped PbSe, while Pisarenko plots show absence of resonant states due to the deep residence of the states and the limited doping concentration confirmed by the calculations. (C) 2018 Elsevier Ltd. All rights reserved.

This research investigated the microstructural evolution of Ni-23.5Cr-2.66Co-1.44Al superalloy foil fabricated by electron-beam physical vapour deposition and annealed at 1000 degrees C. The results showed that the deposited alloy mainly consisted of the gamma-phase. After annealing at 1000 degrees C, the peak moved to a lower 2. degree on the deposited side and to a higher 2 theta degree on the substrate side, which indicated that uniform strain existed at the deposited state and recovery occurred during annealing. With an increase in the annealing time, the (220) diffraction peak increased significantly. The average size of the grains increased and showed zigzag structures after being etched by a mixture of HNO3, HCl and HF etchant. After being annealed at 1000 degrees C for 4 hours, the ultimate tensile strength of the Ni-23.5Cr-2.66Co-1.44Al superalloy foil was improved from 641 to 800 MPa.

This paper reports the Ni-based alloy sheets which were produced by electron-beam physical vapour deposition and further aluminisation. The microstructures of the as-deposited and aluminised sheets were characterised by scanning electron microscope, X-ray diffraction, and so on. It is found that the as-deposited Ni-base alloy sheets present a Ni-based solid solution structure, and the microcrystal grain was compact, uniform and no precipitation. When the alloy sheets have been aluminised at 630°C, the phase structure changed from Al3Ni to Al3Ni2 during heat treatment period. The thickness of every layer was no more than 10 µm. The coating was compact and a small amount of aluminium-rich region appeared in a small area. The interface between coating and substrate was clear and smooth, and macro-defect-free.