Microstructure, thermal, mechanical and tribological properties of Cu composites reinforced with Ag-decorated Ti3C2Tx nanosheets

Aerospace, rail transportation, and electronics require Cu-based materials with high thermal conductivity together with adequate mechanical and tribological performance. However, the relatively low strength, hardness, and wear resistance of Cu limit its use under demanding service conditions. Herein, Ti 3 C 2 T x MXene nanosheets were decorated with Ag nanoparticles, and Ti 3 C 2 T x @Ag/Cu composites were fabricated by ball milling followed by fast hot-press sintering. Ag nanoparticles were uniformly distributed on the Ti 3 C 2 T x surfaces, and the addition of Ti 3 C 2 T x @Ag progressively refined the Cu matrix grains from 5.31 μm in pure Cu to 1.24 μm at 10 vol% reinforcement. The 3 vol% Ti 3 C 2 T x @Ag/Cu composite exhibited the best strength–ductility balance, with an ultimate tensile strength of 288.5 MPa and an elongation of 41.8%, compared with 255.3 MPa and 37.6% for pure Cu, respectively. The hardness increased continuously from 48 to 116 HBW, whereas thermal conductivity showed a non-monotonic dependence on reinforcement content. Ti 3 C 2 T x @Ag produced only a modest change in the average friction coefficient but markedly improved wear resistance; the wear rate decreased from 21.24 × 10 −5 mm 3 ·(N·m) −1 for pure Cu to 6.29 × 10 −5 mm 3 ·(N·m) −1 at 10 vol%, corresponding to a 70.4% reduction. Worn-surface, wear-debris, and cross-sectional observations indicate that the improved wear resistance is mainly associated with suppressed cracking and large-scale material spalling, while friction-induced mechanical mixing and oxidation may provide an additional contribution. These results demonstrate that Ag-decorated Ti 3 C 2 T x is an effective reinforcement for jointly regulating the mechanical, thermal, and tribological behavior of Cu composites.