Effect of Impurities on the Phase Composition and Properties of a Wrought Al–6% Cu–4.05% Er Alloy

The effect of impurities on the phase composition and properties of a wrought alloy of the Al–Cu–Er system has been investigated in this work. According to the results of the scanning electron microscopy and X-ray diffraction analysis, Al 8 Cu 4 Er, Al 3 Er, and Al 3 Er 2 Si 2 particles of phases of crystallization origin are present in the structure of the alloy. After annealing at 605°C, the Al 8 Cu 4 Er and Al 3 Er phases have compact morphology close to spherical with a maximum size of particles up to 3 μm, and the Al 3 Er 2 Si 2 phase has a needle shape with a length of up to 15 μm. No needle-shaped particles have been detected in the structure after rolling, which indicates the fragmentation of the Al 3 Er 2 Si 2 phase. Iron and silicon impurities do not have a significant effect on the alloy recrystallization, but somewhat increase its hardness after annealing at low temperatures (to 250°C). After annealing at 100 and 150°C, the investigated alloy shows a sufficiently high level of mechanical properties: according to the results of tests for uniaxial tension, its proof stress is 277–310 MPa and the ultimate strength is 308–350 MPa, which is 10–30 MPa more than that in the alloy without impurities.