STUDY OF THE EFFECT OF HAFNIUM ADDITIVES IN ALLOY 1570 ON THE ABILITY OF Al3Sc PARTICLES TO INHIBIT RECRYSTALLIZATION PROCESSES

10.25712/ASTU.1811-1416.2024.04.012

Abstract

The study addresses the effect of hafnium on 1570 alloy anti-recrystallization properties. 1570 alloy and its modifications, containing 0.2 % and 0.5 % weight hafnium, were examined using transmission electron microscopy in as-cast and homogenized states. It was found out, that 0.2 % weight hafnium addition and 4-hour annealing at 370 °С results in reduction of precipitated particles amount as compared to 1570 alloy. The particles amount reduction continues with hafnium content increase to 0.5 % weight. Recrystallization retarding and driving forces theoretical calculations demonstrate, that recrystallization is possible in the alloys with 0.5 % weight hafnium content at high Zener-Hollomon parameter values. Annealing at 440 °С leads to particles amount increase with their size reduction in hafnium containing alloys. Intensive particles sizes reduction and particles amount increase are observed in the alloys with 0.2 % weight hafnium content. As a result, recrystallization is inhibited in the alloys with hafnium additions at any Zener-Hollomon parameter value, discussed in this study. In the alloys, containing no hafnium, annealing temperature increase, in the opposite way, leads to the particles amount decrease and size increase. As a result, the retarding force slightly decreases, but it is still sufficient for complete recrystallization processes inhibition.