Study on Microstructure and Mechanical Properties of Core–Shell-Structured Ti@Ti_xN Reinforced Al Composite Prepared by Pressure Infiltration

In this research, a nitrogenized shell layer was formed on the surface of Ti powder in a high-temperature N₂ environment, resulting in core–shell-structured Ti@Ti_xN powder. Using this as a reinforcement, Ti@Ti_xN/Al composite was successfully designed and fabricated via pressure infiltration method. The Ti_xN layer consists of a double-layered spherical shell structure, with TiN as the outer layer and Ti₂N as the inner layer. After the composite was fabricated, no intermetallic compounds between Ti and Al were observed at the interface, as the Ti_xN layer effectively prevented the reaction between Ti and Al. The tensile strength, yield strength, and elongation of the Ti@Ti_xN/Al composite were 173 ± 7.7 MPa, 115 ± 8.1 MPa, and 7.5 ± 0.55%, respectively. Both the strength and hardness were significantly improved compared to the pure Al matrix. Observations of the tensile fracture surface revealed severe interfacial debonding at the interface, and the reinforcement did not exhibit significant coordinated deformation with the matrix. This suggests that future research could focus on strengthening the matrix by adding alloying elements and improving the interfacial bonding to enhance the performance of the composite.