THE EFFECTS OF CYCLE ANNEALING TEMPERATURE ON THE STRUCTURE AND PRECIPITATES OF AN Al-6Mg-Mn-Sc-Zr ALLOY

摘要

The effect of cycle annealing temperature on the grain structure and precipitates of an Al-6Mg-Sc-Zr alloy was studied. During cycle annealing between 200～600 °C, the cold rolling deformation grain structure was very stable up to 500°C, indicated a high recrystallization temperature. The evolution of the primary Al3 (Sc, Zr) and (Fe, Mn) Al6 precipitates was inconspicuous below 500°C but segregated along boundaries when the temperature was higher. The size of β-phase precipitates changed from fine dots into large globularity. It distributed homogenously and continuously at low temperature, then evolved into discontinuous at elevated temperature and again in a continuous network along boundaries at 600°C. The alloy held a microhardness of about 110 HV/Map up to 450°C. It was believed this evolution of grain structure and precipitates with the cycle annealing temperature was mainly due to the existence of the secondary Al3 (Sc, Zr) precipitates.