In carbon fiber reinforced thermoplastic composites (CFRTP), the strength of the interface between the carbon fiber (CF) and the thermoplastic resin matrix has a significant impact on its overall mechanical properties. To improve the interfacial properties between CF and polyamide 6 (PA6), nano-sized Fe₃O₄ was introduced to the CF surface for synergistic modification using the polymerization and adhesion characteristics of dopamine (DA). Through simple immersion co-deposition, the poly-dopamine/nano-Fe₃O₄ (PDA/Fe₃O₄) coating was constructed on the CF surface by oxidative self-polymerization of DA. The microstructure and chemical characteristics of the CF surface before and after modification were characterized. The results show that adding the PDA/Fe₃O₄ sizing agent significantly improves the roughness and chemical activity of the CF surface, and strengthens the mechanical engagement and chemical interaction between the fiber and resin matrix. Compared with unmodified CF/PA6 composites, the prepared modified CF/PA6 composites exhibit excellent mechanical properties, with their bending strength and interlaminar shear strength increased by 30.8% and 29.1%, respectively.

Previous experimental and computational results have confirmed that the thermal conductivity of a two-dimensional (2D) material can be considerably affected by strain. Numerous attention has been paid to explore the relevant mechanisms. However, the strain effects on the interfacial thermal conductance (ITC) of 2D heterostructure have attracted little attention. Herein, the non-equilibrium molecular dynamics (NEMD) simulations were conducted to the graphene/hexagonal boron nitride (GR/h-BN) heterostructure to investigate the strain effects on the ITC. Three types of strains were considered, i.e., tensile strain, compressive strain, and shear strain. The results indicate that the strain can adjust the ITC for the GR/h-BN heterostructure effectively, and the strain loading direction also influences the ITC. Generally, the tensile strain reduces the ITC of the heterostructure, in addition to the BN-C system at small tensile strain; both the compressive strain and shear strain increase the ITC, especially at a small strain. For the NB-C system, it is more sensitive to the strain loading direction and the yx shear strain of 0.06 is the most effective way to strengthen the ITC. Our results also show that the out-of-plane deformation weakens the in-plane vibration of atoms, leading to a reduction of the interfacial thermal energy transport.

We conducted molecular dynamics (MD) simulations of tension and compression along the <112> direction and MD simulations of compression along the <110> and <111> directions on nanolaminated graphene/Cu (NGCu) composites to investigate the effects of the incorporated graphene and the deformation mechanisms related to the loading direction. The deformation behavior and the defect structures were found to be strongly dependent on the loading conditions. An asymmetric tension-compression deformation behavior was thus found in graphene/Cu nanolaminates under the <112> loading, which was dominated by stacking faults and deformation twins formed by dislocation slide under tension and compression, respectively. High density and ordered nanotwins were formed at the graphene/Cu interfaces. Two different formation mechanisms of the twins were found under the <112> compression, and the nucleated twins were easy to be thickened with the assistance of the graphene wrinkles. Multiple twins were formed under the <110> compression by the dislocation cross-slip. This study provides a way to introduce graphene reinforcement and twin boundary to Cu matrix composites and design nanotwinned graphene/Cu composites with excellent mechanical performance.