Growth of α phase during lamellar decomposition of Ti-48Al-7Nb-2.5V-1Cr alloy

This paper has investigated the growth of α grain during lamellar decomposition of Ti-48Al-7Nb-2.5V-1Cr alloy. In the (α + γ) phase region, the α grains have started to grow by consuming the adjacent α grains, accompanied by decomposition of γ lamellae (γ_L). Since the growth rate of α grains is faster than the decomposition of γ_L, the growth of the α grains is hindered by the γ_L, while the hindering effect decreases with the γ_L decomposition. Once the hindrance of the γ_L is gone, the α grains will continue to grow and the grain size can even reach the millimetre level. The α grain growth does not show a specific pattern. The growing α grain may also be consumed by the adjacent α grains, resulting in irregular grain morphology.