Effect of Mo nanoparticles on microstructure and mechanical properties of Cu alloys by self-propagating and spark plasma sintering

Cu alloys strengthened with Mo nanoparticle, with Mo contents of 2 at.%, 4 at.%, 6 at.%, 8 at.%, and 10 at.%, were fabricated by self-propagating high-temperature synthesis, followed by two-step hydrogen reduction and spark plasma sintering. The microstructures, mechanical properties, and thermal conductivity of these Cu-Mo alloys were investigated. The results reveal that two-step hydrogen reduction effectively reduces the average Mo particle size to 13.8 nm compared to one-step reduction. With increasing Mo content, the average grain size of Cu initially decreases but then increases due to the segregation of Mo particles. Notably, the Cu-6 at.% Mo alloy exhibits the smallest average grain size of 0.46 mu m, with dispersed nanoscale Mo particles of 25.6 nm. The Cu-6 at.% Mo alloy demonstrates superior mechanical properties, with a tensile strength of 405.0 MPa and an elongation of 24.9 %. Furthermore, the Cu-6 at.% Mo alloy has a high thermal conductivity of 320.0 Wm(-1)K(-1) even at 400 degrees C and a high electrical conductivity of 82.3 % IACS at room temperature. This work offers valuable insights for the design of advanced Cu composites suitable for heat sink applications.