Guorong Cui

Titanium/carbon-fiber composite hybrid joints require robust metal/polymer interfaces to exploit the complementary properties of titanium alloys and fiber-reinforced polymers. In this study, TA15 composite coatings with dry-GNP/TA15-powder mass ratios of 0.00-1.00 wt% were deposited by doctor blade and vacuum-sintered at 1050 °C before co-curing with carbon-fiber/epoxy prepreg. Coating morphology, phase and chemical-state evolution, apparent wettability, single-lap shear strength (SLSS), and fracture morphology were evaluated. The 0.25 wt% formulation produced the highest measured group-mean SLSS (30.9 MPa), compared with 10.2 MPa for the untreated TA15 control and 16.5 MPa for the GNP-free porous coating. SEM revealed an interconnected sintered-particle network that enables epoxy penetration and mechanical interlocking. Raman spectroscopy, XPS, XRD, and EDS were collectively consistent with carbon redistribution and Ti-C-rich regions at the titanium side of the interphase. Fractography showed a pronounced shift from predominantly adhesive failure for the untreated TA15 control to resin-rich/cohesive failure for the 0.25 wt% formulation, with Ti-side residual-resin coverage increasing from less than 5% to approximately 99%. The results support hierarchical strengthening through porous mechanical interlocking, titanium-side chemical modification, and improved load transfer into the polymer-rich region.

1. Carbon fiber reinforced polymer (CFRP) has been widely applied in aerospace field with their excellent performance: light-weight, high specific strength, fatigue resistance and anti-corrosion, e...

Laser micro-drilling was applied to Fe substrates to enhance the interfacial properties of carbon fiber-reinforced polymer/iron laminates. This architecture is referred to as a resin-interlocked Fe-CFRP hybrid composite. Inspired by human hair follicles’ exceptional adhesion and filling efficiency, novel biomimetic frustum-integrated cylindrical cavities were engineered for Fe surface modification. Experimental results demonstrate that laser-processed surfaces with varied hole geometries (conical, conical frustum, cylindrical, and frustum-integrated cylindrical cavities) exhibit significantly improved interfacial performance compared to untreated Fe controls. Specifically, RI-Fe/CFRP specimens containing frustum-integrated cylindrical cavities achieved the highest shear strength, with a 44.8% increase over non-drilled counterparts. Subsequent molecular dynamics simulations confirmed the critical role of the cavity geometry, demonstrating that the frustum-integrated cylindrical cavity elevates the Fe–Diglycidyl ether of bisphenol-A interfacial energy and van der Waals interactions by 45.44% and 50.66%, respectively, versus the flat surface. The interfacial energy enhancement mechanism via distinct hole configurations was systematically studied. Furthermore, comprehensive micro-hole topology analysis elucidated the reinforcement mechanism in resin-interlocked Fe-CFRP hybrid composites. Results demonstrate that frustum-integrated cylindrical cavities significantly enhance DGEBA-3,3′-diaminodiphenyl sulfone fluidity during interface simulation, promoting mechanical interlocking and optimized resin-filling efficiency. Laser micro-drilling effectively improves Fe-DGEBA interfacial performance. These findings provide critical insights for designing high-performance composites in aerospace and automotive applications.

In this work, a design approach for achieving arbitrary acoustic power splitting is proposed. Several space-varying air slits are adopted to connect multiple acoustic cavities, thus realizing quantum-like adiabatic transfer in acoustic systems. By altering the coupling actions between composing cavities, the splitting ratios can be customized on demand. The one to m-port power splitting is achieved in planar as well as spatial configurations, showing an excellent applicability to numerous different scenarios. Remarkably, the acoustic waves from adjacent output ports not only have desired splitting ratios, but also have opposite phases. Hence, a broadband and asymmetric acoustic metamaterial is further constructed, through which the beam splitting and asymmetric wave transmission behaviors can be realized simultaneously in a free space. The proposed acoustic power splitter design offers a simple configuration, broadband performance, and high flexibility, making it a promising candidate for applications in acoustic detection, sensing, and communication.

Graphene nanoplates (GNPs)/TA15 composites were fabricated by pre-sintering and hot extrusion. During a room temperature tensile test, the dislocation was generated in grains. With increasing strain, the dislocation piled up along the interface between GNPs and Ti matrix, leading to stress concentration and microcracks. Then, the microcracks extended to GNPs or along the interface. The GNPs cracked under the shear force and the GNPs pulled out along with the crack propagation along the interface. This work provides a new sight in the room temperature tensile fracture behaviors.