Tuning recrystallization uniformity in TC18 alloy via α configuration design

The effect of α lamellae configuration on recrystallization uniformity in TC18 alloy was systematically investigated. The results indicated that with increasing the thickness of α lamellae, the β grain size uniformity factor (statistics standard deviation) exhibits a tendency of decreasing and then increasing. The mechanism of microstructural homogeneity regulation through the interplay between α dissolution and β recrystallization nucleation and growth was elucidated. When the α lamellae are thin, β recrystallization nucleation primarily occurs through grain boundary-induced boundary migration mechanism, characterized by unidirectional nucleation from high-strain to low-strain regions, resulting in excessive growth of certain β grains. However, the thick α lamella results in asynchronous processes of β recrystallization nucleation and growth near the grain boundaries and within the grains, ultimately leading to deteriorated β grain size uniformity.