Microstructure, mechanical properties and tribological properties of copper composites reinforced with ball-milled Ti–Al intermetallic

Mechanical ball-milling combined with fast hot pressed sintering was employed to fabricate copper matrix composites incorporating Ti–Al intermetallic of varying sizes and morphologies (BMTA-Cu). The effects of different ball milling times on the microstructure, mechanical properties, and tribological performance of the composites were systematically investigated. The results indicate that with prolonged ball milling time, the size of Ti–Al particles first decreased and then increased. The minimum particle size (<10 μm) was achieved at a milling duration of 48 h. Furthermore, the Cu composite reinforced with Ti–Al particles milled for 48 h exhibited the best overall performance. This is primarily attributed to the formation of Cu 2 TiAl nanocrystals during sintering, which were surrounded by micron-sized Cu grains, creating a heterogeneous structure (a bimodal grain size distribution). This unique microstructure demonstrated a synergistic enhancement of strength and toughness, leading to an ultimate tensile strength of 407.4 MPa and a high elongation of 39.4% in the Cu composite. As the ball milling time increases, the frictional properties first decrease, then improve, and finally deteriorate again. However, the composite with 48h milled Ti–Al reinforcement showed the optimal tribological properties, characterized by the most stable friction coefficient and the lowest wear rate across all tested sliding velocities. The in-situ formation of nanoscale Cu 2 TiAl particles from Ti–Al precursors led to a synergistic enhancement in the mechanical properties and toughness of the Cu composite, which significantly improved its wear resistance.