1998 Volume 39 Issue 1 Pages 49-56
The β⁄α″ duplex phase structure formed by quenching from β phase region in a Ti–10V–2Fe–3Al alloy was aged at 673 and 873 K to produce α phase particles. Since the α phase particles exhibit the morphology similar to that of α′ martensite, the processes of transformation have been analysed by the crystallographic theory of martensite.
At 673 K, very fine spherical ω phase particles precipitate initially and then fine α platelets in specific directions replace with them as bands. At 873 K, on the other hand, coarse monolithic α phase plates precipitate directly in the parent β phase. The orientation relationships between α and β phases in both cases are close to that of Burgers. The habit planes for both the α platelets and the α plates lie close to the (1\bar22)β and the (1\bar11)β, respectively. The results can be explained consistently in terms of Bowles and Mackenzie theory by considering the condition that the elastic stress due to the shape change is relaxed by slips within the matrix.