Resistance to recrystallization due to Sc and Zr addition to Al–Mg alloys

Aluminum alloys containing scandium exhibit specific properties. Scandium is one of the alloying elements that produce a very intensive precipitation hardening effect. Due to the low critical cooling rate for Sc retention in Al solid solution, high Sc solute concentration is obtained in Al–Sc castings even in massive ingots, which cool down very slowly. Casting is usually followed by homogenization annealing or forming at relatively high temperatures. Solid-solution decomposition resulting in overageing occurs during these procedures. The Al3Sc hardening precipitates dissolve at very high temperature and, for this reason, a separate solution annealing treatment is not feasible. The specific behavior of Al3Sc phase and its substantial influence on the softening processes and weldability in Sc containing Al alloys have been the subject of intensive research. The paper presents the results of research aimed at studying the effect of Sc and Zr on the resistance to recrystallization in Al–Mg–Sc–Zr alloys.