Integrated Fabrication of C_f/Al Composite and Joining with TC4 via Liquid-Solid Infiltration Extrusion: Microstructure Evolution and Fracture Behavior

Efficiently joining TC4 and carbon fiber-reinforced aluminum matrix (C_f/Al) composite greatly expands the applications of composite in the aerospace industry. In this study, a liquid-solid infiltration extrusion (LSIE) process was proposed to effectively join C_f/Al composite with TC4 while preparing them. The microstructure, interfacial properties, and phase composition of the Ti-C_f/Al interface were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The mechanical response and failure modes of the composite were investigated. The results show that a TiAl₃ intermetallic transition layer with a width of about 10 μm was successfully formed at the interface of TC4 and C_f/Al composite. Compared with the C_f/Al composite, the presence of this transition layer significantly increased the shear strength of the joint by 35.8 pct. In addition, through the unique deformation mechanism of the transition layer, the joint effectively disperses the stress concentration and delays the crack extension, thus realizing the transformation of the composite material from bending brittle fracture to multi-crack progressive damage mode. Meanwhile, the deformation behavior and strengthening mechanism of the TiAl₃ transition layer on the composite are also deeply explored in this study. This successful and simple toughening strategy provides a feasible way to realize the application of continuous C_f/Al composite.