Abstract: Microstructure and room temperature tensile and impact properties of Ti6321 alloy bars under different annealing processes were systematically analyzed. The results show that when the single annealing process is adopted, with the increase of annealing temperature, the content of primary α phase shows a trend of first decreasing and then increasing and finally decreasing, the content of original secondary α phase gradually decreases, and the strength shows the trend of first decreasing and then rising, and the impact absorbed energy first decreases and then increases. When the multiple annealing process is adopted, with the increase of annealing temperature in the first stage, the content of the primary α phase decreases, the strength decreases, but the impact absorbed energy increases. With the increase of annealing temperature in the second stage, the width of the secondary α phase layer increases, the strength decreases, while the impact absorbed energy increases. When the triple annealing system of 960 ℃×80 min/WQ+920 ℃×80 min/AC+550 ℃×240 min/AC is adopted, the alloy has the best strength and toughness matching.

Key words: Ti6321 alloy, annealing process, microstructure, room temperature tensile properties, impact property