Synthesis of Copper Based Composites Reinforced with (Ni,Cu)₃Al Intermetallic via Low Energy Ball Milling

Abstract

In this study, intermetallic particles were successfully dispersed in a copper matrix using mechanical alloying with a low-energy planetary mill. The (Ni,Cu)₃Al intermetallic phase was added at 5, 10, and 15 wt% concentrations, with particle sizes ranging from 8 µm to 15 µm. The resulting powders were compacted and sintered at 700°C for 30 minutes in an argon atmosphere. Microstructural characterization was performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), while surface hardness was evaluated through microhardness testing. XRD analysis confirmed that no new phases were formed and no phase changes occurred during the milling process. The microhardness results showed a notable 20% increase in hardness at 10 wt% of intermetallic reinforcement compared to the base copper material. This improvement is attributed to the uniform dispersion of the intermetallic particles, which enhanced the mechanical properties. However, a decrease in microhardness was observed at 15 wt%, likely due to increased microporosity, which reduced cohesion between copper particles and negatively affected the composite’s performance. These findings suggest that an optimal intermetallic content exists for reinforcing copper via mechanical alloying, with 10 wt% offering the best balance between dispersion, microstructure, and mechanical strength.

Keywords:
Powder copper; Microhardness; Intermetallic; Porosity