Mechanochemical Synthesis of Cu–Al Alloyed Powders and Their Consolidation by Spark Plasma Sintering

The mechanochemically synthesized Cu–20 wt % Al alloys are studied by the X-ray diffraction analysis and scanning electron microscopy. It is shown that, after 20 min of mechanical activation, the single-phase intermetallic compound Cu9Al4 with crystallites ~3 nm in size, low microstrains (~0.03%), and particle size in the range from 0.2–0.4 to 2–4 μm is formed. The morphological characteristics of the solid solution of aluminum in copper, which has been mechanochemically synthesized from the Cu–10 wt % Al alloy, are studied. It is demonstrated that the solid solution is composed of platelike particles 10–50 μm in planar size and 2–10 μm in thickness. The scanning electron and optical microscopy data show that the Cu(Al) solid solution produced by the spark plasma sintering at 700°С are characterized by the low residual porosity (<0.5%). The Vickers hardness is 290 ± 30 HV.