(Si/graphite)@C and (Si/graphite/graphene)@C were synthesized by coating asphalt-cracked carbon on the surface of a Si-based precursor by spray drying, followed by heat treatment at 1000 °C under vacuum for 2h. The impact of graphene on the performance of silicon–carbon composite-based anode materials for lithium-ion batteries (LIBs) was investigated. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) images of (Si/graphite/graphene)@C showed that the nano-Si and graphene particles were dispersed on the surface of graphite, and thermogravimetric analysis (TGA) curves indicated that the content of silicon in the (Si/graphite/graphene)@C was 18.91%. More bituminous cracking carbon formed on the surface of the (Si/graphite/graphene)@C due to the large specific surface area of graphene. (Si/Graphite/Graphene)@C delivered first discharge and charge capacities of 860.4 and 782.1 mAh/g, respectively, initial coulombic efficiency (ICE) of 90.9%, and capacity retention of 74.5% after 200 cycles. The addition of graphene effectively improved the cycling performance of the Si-based anode materials, which can be attributed to the reduction of electrochemical polarization due to the good structural stability and high conductivity of graphene.

The effects of Si, Fe and Zr elements on the high temperature properties and microstructure of ultrathin 3003mod aluminum alloy fins were studied by means of high-temperature tensile tests, sagging tests and microstructure analyses. The results show that the alloying of Si, Fe, and Zr elements formed a large amount of nano-scale α-Al(Mn,Fe) Si and Al₃Zr particles, and significantly reduced the number of micro-scale coarse Al₆(Mn,Fe) particles in the 3003mod aluminum alloy, exhibiting 5 to 10 MPa higher strength and better sagging resistance than 3003 aluminum alloy at the same temperature. The variations in properties such as high-temperature mechanical properties, sagging resistance and elongation below 400 °C were ascribed to the high-stability nanoparticles effectively preventing recovery and grain boundary migration, as well as reducing the nucleation cores of recrystallization. The nanoparticles in 3003mod aluminum alloy were coarsened significantly at 500 °C, and the grains were completely recrystallized and coarsened, resulted in a significant decrease in strength, sagging resistance and elongation compared with these at 400 °C.

In the present study, the hot roll bonding process of 7000 series aluminum alloy laminated materials was numerically simulated and investigated using the finite element method, and the process parameters were experimentally verified by properties testing and microstructure analysis after hot roll bonding. In the roll bonding process of aluminum alloy laminated materials, the effects of the intermediate layer, pass reduction ratio, rolling speed and thickness ratio of component layers were studied. The results of finite element simulations showed that the addition of a 701 intermediate layer in the hot roll bonding process could effectively coordinate the deformation of the 705 layer and 706 layer and prevented the warping of the laminated material during hot rolling. It is recommended to use a multi-pass rolling process with small deformation and high speed, and the recommended rolling reduction ratio is 20%~30%, the hot rolling speed is 1.5~2.5 m/s and the thickness ratio of the 705 layer and 706 layer is about 1:5. Based on the above numerical results, five-layer and seven-layer 7000 series aluminum alloy laminated materials were prepared by the hot roll bonding process. The results showed that metallurgical bonding was realized between each component layer, and no delamination was observed from the tensile fracture between the interfaces of component layers. The tensile strength of the prepared laminated materials decreased with the increase in the thickness ratio of the 705 layer, and the bonding strengths of the laminated materials were in the range of 88–99 MPa. The experimental results verified the rationality of the process parameters recommended by the numerical simulations in terms of warping and delamination prevention.

Coarse particles in Cu-0.39Cr-0.24Zr-0.12Ni-0.027Si alloy were studied with scanning electron microscopy and transmission electron microscopy. Three types of coarse particles were determined: a needle-like Cu₅Zr intermetallic phase, a nearly spherical Cr₉.₁Si₀.₉ intermetallic phase and (Cu, Cr, Zr, Ni, Si)-rich lath complex particles. The crystallographic orientation relationships of the needle-like and nearly spherical coarse particles were also determined. The reasons for formation and the role of the coarse phases in Cu-Cr-Zr alloys are discussed, and some suggestions are proposed to control the coarse phases in the alloys.

In this work, a series of urchin-like Ce(HCOO)₃ nanoclusters were synthesized via a facile and scalable microwave-assisted method by varying the irradiation time, and the structure–property relationship was investigated. The optimization of the reaction time was performed based on structural characterizations and electrochemical performances, and the Ce(HCOO)₃-210 s sample shows a specific capacitance as high as 132 F g⁻¹ at a current density of 1 A g⁻¹. This is due to the optimal mesoporous hierarchical structure and crystallinity that are beneficial to its conductivity, offering abundant Ce³⁺/Ce⁴⁺ active sites and facilitating the transportation of electrolyte ions. Moreover, an asymmetric supercapacitor based on Ce(HCOO)₃//AC was fabricated, which delivers a maximum energy density of 14.78 Wh kg⁻¹ and a considerably high power density of 15,168 W kg⁻¹. After 10,000 continuous charge–discharge cycles at 3 A g⁻¹, the ASC device retains 81.3% of its initial specific capacitance. The excellent comprehensive electrochemical performance of this urchin-like Ce(HCOO)₃ offers significant promise for practical supercapacitor applications.

Quench–polish–quench (QPQ) of 40Cr steel was performed to improve its tribological properties and corrosion resistance, thereby enhancing the service performance of components such as gears and bearings. The 40Cr steel was treated by QPQ at 580 °C and 620 °C for 90 or 120 min. Optical microscopy (OM, Sunny Group, Ningbo, China), scanning electron microscopy (SEM, Hitachi, Tokyo, Japan), and X-ray diffraction (XRD Rigaku Corporation, Tokyo, Japan) were used to characterise the microstructure and phase constitution. Ball-on-disk tribometry, electrochemical tests, and salt spray tests in 3.5 wt.% NaCl evaluated surface performance. At 580 °C, a composite structure of Fe₃O₄ and ε-Fe₂₋₃N formed on the surface. When the temperature rose to 620 °C, ε-Fe_2–3N gradually transformed into γ′-Fe₄N. Within the scope of this study, the diffusion layer depth exhibits an approximately linear relationship with increasing processing temperature and holding time, and the surface hardness is 67–112% higher than that of the untreated sample. After QPQ treatment, the wear mechanism changed from adhesive wear to abrasive wear. However, under the treatment conditions of 620 °C × 120 min, brittle surface spalling increased roughness, thereby increasing the coefficient of friction. As treatment time increases, nitrogen atoms continue to diffuse outward as Fe₂N transforms to the γ′ phase. This increases the composite layer’s porosity and decreases its corrosion resistance. The best corrosion resistance was observed at 580 °C for 120 min, with a corrosion potential of −0.4325 V, corrosion current density of 1.80 × 10⁻⁶ A·cm⁻², and polarisation resistance of 24,500 Ω. Corrosion performance depends on overall surface integrity. Porosity morphology strongly influences this property. For 40Cr steel, the results show that surface properties are primarily determined by the quality of the compound layer’s microstructure. Specifically, density, phase-composition stability, and defect control are more important than the commonly held view of layer thickness.