In this study, a CrFeMoNbTiW high-entropy alloy (HEA) coating was prepared on a Q245R steel (American grade: SA515 Gr60) substrate by means of laser cladding. The effects of annealing temperature on the microstructure and wear resistance of the CrFeMoNbTiW coating were investigated using X-ray diffraction (XRD), a scanning electron microscope (SEM), a Vickers hardness tester and a roller friction wear tester. The results showed that the coating was mainly composed of body-centered cubic (BCC) solid solution and face-centered cubic (FCC) structural (Nb,Ti)C carbides prior to annealing, exhibiting an interdendritic structure and needlelike dendritic crystal structure with average microhardness of 682 HV_0.2. The coarsening of the dendrite arms increased gradually after a 10-h long annealing treatment at 800 °C, 900 °C and 1000 °C, and a small amount of Laves phase was produced. After annealing, the highest microhardness value of the as-annealed coating reached 1176 HV_0.2, which represents an increase of approximately 72.5% compared to that of the as-deposit coating. The wear resistance testing results imply that this type of coating retains good wear resistance following the annealing treatment and that its wear resistance increases in proportion to the annealing temperature in a range from 800 °C to 1000 °C.

CoO and CoAl layered double hydroxide (CoAl-LDH) are both promising active electrode materials for pseudocapacitors. It is of great significance to integrate the advantages of both materials and design ingenious electrode structures to achieve high electrochemical performance. Herein, 3D core–shell CoO@CoAl-LDH nanobouquet arrays on Ni foam were fabricated via two-step hydrothermal growth methods, where CoAl-LDH nanoflakes regularly grew on the surface of CoO nanosheets. The composite exhibits superior specific capacitance (2031.2 F g⁻¹ at 1 A g⁻¹) and desirable cycling stability (88.2% after 5000 cycles at 16 A g⁻¹). Asymmetric supercapacitors (ASCs) devices were also assembled using an as-synthesized CoO@CoAl-LDH composite as a positive electrode and activated carbon (AC) as a negative electrode. The electrochemical test of ASCs provides a specific capacitance of 195.6 F g⁻¹ at 1 A g⁻¹, and the devices retained approximately 85% of the capacitance after 5000 cycles. The ASCs display a high energy density of 69.55 W h kg⁻¹ at a high-power density of 800 W kg⁻¹ and remained at 29.2 W h kg⁻¹ even at a higher power density of 12 800 W kg⁻¹. The electrochemical mechanism was discussed. This work offers a meaningful perspective to explore the possibility of supercapacitor applications of LDH-based materials.

7050 aluminium alloy is a superior material used in the areas of aerospace and automobile manufacturing. In this work, homogeneous cast cylinder samples of 7050 aluminium alloy with size of Φ80 mm × 100 mm were compressed isothermally at 350°C with compressive strain rate of 0.1 s⁻¹,1 s⁻¹, and 10 s⁻¹, respectively. The samples were then processed into standard tensile specimens, and then tensile testing was done by using the GL8305 universal testing machine. The grain sizes and fracture morphology were analyzed by the SEM observation and cellular automaton (CA) method. The effect of compressive strain rate on microstructure and mechanical properties of 7050 aluminium alloy was investigated. The results show the following. (1) Grain refinement occurred after compression. The grain sizes of the samples decrease with the decrease of compressive strain rate. The grain sizes in the radial edge and the axial center of the cylinder samples are the smallest. (2) The tensile strength and breaking elongation rate were improved when compared to the original alloy. The mechanical properties of samples compressed with compressive strain rate of 0.1 s⁻¹ are the best. (3) The fracture morphology of the samples shows that the fracture of the samples is ductile fracture. The sizes and depths of dimples increased with the decrease of grain sizes.