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The mechanical properties of composites are closely related to the interfacial behavior, especially under the hygrothermal circumstance. A catalytic sizing agent of titanium epoxy is designed to enhance interfacial, mechanical, and anti-hygrothermal properties of high modulus carbon fiber (HMCF)/cyanate ester composites simultaneously. The mechanisms of interface enhancement and low hygroscopicity of composites are investigated. The titanium epoxy is synthesized and its catalytic effect on the curing of cyanate ester is proved. The interfacial properties of HMCF composites with catalytic sizing agents are improved to 95.5 MPa, which is attributed to the interphase with high crosslinking density and sufficient triazine rings and oxazolidinone structure due to preferential curing induced by interfacial catalysis, stimulating the smooth transition of interphase modulus. Further, the formed interphase exhibits few interface defects and low content of hydroxyl groups, which changes the moisture diffusion path and reduces saturated water absorption of composites to only 0.36 %, resulting in the release of interfacial wet stress concentration and high retention of mechanical properties in hygrothermal environment. The resultant composites with high stiffness, excellent temperature resistance, superior dimensional stability and low moisture absorption are expected to be applied to high-orbit space, aerospace, precision instruments. [Display omitted] • The interfacial, mechanical, and anti-hygrothermal properties of composites are improved via catalytic sizing agents. • Catalytic sizing agents induce preferential curing of resin at the interface. • Catalytic sizing agents stimulate the smooth transition of modulus and increase IFSS. • The interphase with high interfacial adhesion and low hygroscopicity changes the moisture absorption path in composites. [ABSTRACT FROM AUTHOR]

A nano-scale electrochemical sculpture (NES) method has been developed to enhance the bonding strength of fiber metal laminates (denoted as FMLs-NES). The influence of NES surface treatments on the low velocity impact response and static mechanical behavior of FMLs was systematically investigated and compared with traditional surface treatments such as mechanical polishing and NaTESi anodizing (denoted respectively as FMLs-PS and FMLs-NaTESi). The examination of the damage area and energy absorption under different impact energy levels revealed that the FMLs-NES specimen exhibited the smallest damage area and energy absorption while maintaining the structural integrity after impact. Finite element simulations were conducted to inform the impact damage progression and failure mechanisms, the results indicate that the interfacial failure mainly occurred between the middle titanium sheet and the bottom 90° fiber layer and propagated from the long edge to the center of FMLs. The experimentally validated finite element model can also be employed to optimize the stacking sequence of FMLs and to predict the residual strength after impact, where the FMLs-NES showed the highest residual strength. [Display omitted] [ABSTRACT FROM AUTHOR]