High-temperature tensile behavior and microstructural evolution of cold-rolled Al–6Mg–0.4Sc–0.13Zr alloy

The high-temperature tensile properties and microstructural evolution of Al–6Mg–0.4Sc–0.13Zr alloy prepared by conventional cold rolling at various temperatures were studied. At 573 K, the Al3(ScxZr1−x) particles stabilized the extremely fine subgrains (SG) and submicrograins (SMG). These SG and SMG boundaries acted as effective dislocation sinks, turning into true high-angled boundaries susceptible to consequent sliding. Therefore, the alloy achieved an acceptable ductility with 300% elongation. At 623–723 K, because geometrical sliding was not feasible with rugged grain boundaries and dislocation movement was strongly hindered by the Al3(ScxZr1−x) particles, the alloy exhibited poor ductility. At 773 and 803 K, the Al3(ScxZr1−x) particles began to act as grain stabilizers, and retained fine-grain structure at these high temperatures. As a result, a maximum elongation of 1100% was achieved after deformation at 803 K with a strain rate of 5 × 10−3 s−1.