Mingxu Yang

To enhance the mechanical properties of carbon-fiber-reinforced polymer composites (CFRPs), this study devised a novel three-dimensional web-like “rigid–flexible” surface modification strategy. The synergistic incorporation of carbon nanotubes (CNTs), polydopamine (PDA), and cellulose nanofibers (CNFs) constructed a “three-dimensional nanospider web” modulus transition layer. The modified carbon-fiber (CF-0.1%CNT-PDA-CNF) surface exhibits a three-dimensional network structure, with significantly increased surface roughness. The surface energy increased by 128.60% compared to the desized carbon fiber, thereby improving the wettability of the carbon-fiber surface. The results of both PeakForce-Quantitative Nanomechanical Mapping (PF-QNM) and EDS analyses indicate that a transition layer of a certain thickness initially formed at the interface. At the interface, the modulus exhibits a gradual gradient decrease from carbon fiber to epoxy resin, achieving more efficient stress transfer. The interfacial shear strength (IFSS, 95.71 MPa), interlaminar shear strength (ILSS, 73.19 MPa), tensile strength (701.08 MPa), and flexural strength (934.41 MPa) of the CF-0.1%CNT-PDA-CNF/EP composite material increased by 38.39%, 54.93%, 51.74%, and 64.98%, respectively, compared to the composite material made from desized carbon fiber. Through hydrogen bonding, covalent bonding, and π-π interactions, CNTs, CNFs and PDA formed a “rigid–flexible” transition layer with a modulus gradient at the CF-epoxy interface, achieving a significant enhancement in the mechanical properties of the composite material.

In this paper, pre-extrusion treatment was applied to AZ80 alloy prior to caliber rolling, and microstructural evolution as well as mechanical properties of groove-rolled AZ80 alloy were studied. The results shown that the pre-deformation treatment can enhance the formability of AZ80 alloy and the cracking can be avoided. In addition, the pre-extrusion also resulted in fine grain structure after rolling process. Especially, 8-pass caliber rolling following by pre-extrusion of AZ80 alloy shown uniform and fine dynamic recrystallized (DRX) structure. Besides, the introduction of pre-deformation also promotes more second phases during caliber rolling. Therefore, the mechanical properties shown that the yield strength (TYS), tensile strength (UTS) and elongation after fracture (El.) of pre-extruded AZ80 caliber-rolled bars are 250 MPa, 440 MPa and 15%, respectively, which increased by 72%, 37%, and 88% compared with their as-cast counterparts. The improvement of mechanical properties is attributed to synergy effects of grain refinement, second precipitates strengthening and texture optimization.

The hexagonal boron nitride (h-BN) nanosheets modified by silane coupling agent (KH560) were doped into acrylic acid coating on the surface of galvanized steel to improve its corrosion resistance. H-BN nanosheets modified by KH560 were prepared and characterised by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. The corrosion resistance of the acrylic acid coatings was measured by electrochemical testing. The results show that the corrosion current density of the coating with modified h-BN nanosheets was reduced from 2.2 × 10⁻⁵ A/cm² to 2.3 × 10⁻⁷ A/cm² compared with the acrylic acid coating. The impedance of the composite coating with modified h-BN is 4435 Ω·cm², higher than the BNNS coating (2500 Ω·cm²) and the acrylic acid coating (1500 Ω·cm²). This is due to the physical barrier and electrical insulation properties of the hexagonal boron nitride (h-BN) nanosheets.