Recrystallization features of deformable aluminium-magnesium alloys with scandium

Deformable alloys based on Al-Mg system belong to the group of alloys that cannot be strenthened by heat treatment. These alloys are suitable for production of all types of deformed semiproducts as well as pressed parts and stampings. The most highly alloyed and strong among widely spread deformed alloys based on Al-Mg system are AMg6 and AMg61. The use of AMg6 (Al -6 % Mg) alloy in this type of structures is due to its advantages such as good weldability, high corrosion resistance, sufficient plasticity and good manufacturability. The key strengthening method of these alloys is cold working. The principal shortcomings of the AMg6 alloy are relatively low mechanical properties and instability of hardened state at heating. One of prospective directions of increasing strength of deformable alloys based on Al-Mg system is alloying with scandium. The paper presents the results of investigation of thermal stability of structural state of an Al-Mg alloy containing 0.22 % Sc (01570 alloy) after annealing at different temperatures as well as after subsequent cold deformation. Time-temperature parameters of recrystallization start of hot-pressed rod of 01570 alloy after 4 h holding at 500 °C and 1 h holding at 525 °C are established. It is shown that recrystallization start of hot-pressed samples annealed at 320 °C and deformed by 40 % at room temperature is observed after 10 h of annealing at 400 °C, and for the samples annealed at 450 °C and deformed by 40 % at roome temperature even after 4 h of annealing at 400 °C.