The Microstructure and High-Strain-Rate Superplasticity of the Al–Mg–Ni–Fe–Mn–Cr–Zr Alloy

Abstract

The microstructure, superplasticity characteristics at a subsolidus temperature (540°C), and the room-temperature mechanical properties of an alloy of the Al–Mg–Ni–Fe–Mn–Cr–Zr system have been investigated using the methods of scanning and transmission electron microscopy and uniaxial tensile tests. The alloy has a bimodal particle-size distribution; it contains eutectic particles of Al₉FeNi with an average size of 0.6 μm; and dispersoids with an average size of 75 nm. The particles of the secondary phases ensure grain size of approximately 4 μm after the recrystallization subsolidus annealing of the cold-rolled sheet. Due to the microsize grain structure, the alloy demonstrates a relative elongation to 500% at a subsolidus temperature in the range of the constant strain rates of 5 × 10^–3 to 3 × 10^–2 s^–1, yield stress 215 MPa, and ultimate strength 330 MPa.