Development and characteristics of aluminum-based alloys with ultrafine grain sizes

Ultrafine grain sizes, of the order of approx.0.2 μm, were produced in Al-1.5% Mg and Al-3% Mg solid solution alloys using two different procedures in which the samples were subjected to intense plastic strain. The microstructural stability was evaluated by static annealing over a range of temperatures from 443 to 803 K. Specimens were tested either in tension or in a miniature testing facility using a procedure analogous to four-point bending. The experimental results demonstrate the feasibility of producing submicrometer-grained structures in Al-Mg alloys and they show also the potential for achieving high tensile elongations prior to failure at relatively low testing temperatures.