Synthesis of Copper-Alumina Composites by Mechanical Milling: An Analysis

Copper-based composite materials are widely applied in the field of electronics and electrical engineering as highly conductive materials for operation at high temperatures. In this study, copper-based composites were produced by the powder metallurgy and reinforced with 1.0, 1.5, 2.0, 2.5, and 3.0% vol alumina nanometer sized particles. Powders were mixed by glass ball milling for 6 h at 100 rpm. Samples were compacted at 420 MPa in a steel die and sintered at 900 degrees C for 15 min in an argon chamber. Scanning electron microscopy, X-ray diffraction, Vickers micro-hardness, and tensile tests were performed to analyze the influence of the alumina content on the mechanical, structural, and micro-structural properties of the copper-alumina composites that were manufactured by three steps of the powder metallurgy technique. X-ray diffraction patterns showed that during the ball milling, cold compacting, and sintered steps no new crystalline phases were formed. Scanning electron microscopy images providing information related to the alumina layering that restricted the reinforcement mechanism and the expected improvement in the composite mechanical properties.