Anisotropic microstructures and mechanical properties of textured Ti₃AlC₂/TiAl₃/Al composite

In the present work, a textured Ti₃AlC₂/TiAl₃/Al composite with anisotropic microstructures and properties was successfully prepared by combining multistep ball-milling, flaky powder self-assembly, spark plasma sintering (SPS), and in-situ reaction. The effects of phase constitution and crystallographic orientation on anisotropic strengthening and fracture mechanisms of the composite were discussed. The results show that the preferred orientation of Ti₃AlC₂ flakes was achieved during densification with the Lotgering orientation factor of the textured top surface (TTS) of 0.58. The high surface energy of Ti₃AlC₂ submicron flakes provided the driving force for the low-temperature in-situ formation of TiAl₃. The in-situ formed TiAl₃ further improved the strength of the composite. The//c-axis samples achieved a high flexural strength of 565.9 MPa. The analysis of the flexural fracture surfaces shows that the fracture modes of Ti₃AlC₂ flakes include basal plane cleavage, delamination, kinking, particle pull-out, and prismatic plane fracture, which in turn affects the toughness of the samples with different loading directions. Particle pull-out of the Ti₃AlC₂ flakes is the primary mechanism to improve the toughness. This novel technical route provides a new idea for the design of metal matrix composites.