Microstructural development of a gas-atomized and hot-pressed super-α2 alloy

A variety of heat treatments have been employed to explore the microstructure in Ti-25Al-10Nb-3V-1Mo alloy prepared by gas atomization and hot pressing. These treatments include quenching by oil cooling and water cooling and aging at temperatures between 530 C and 950 C. Quenching transformations from the β-phase field include the formation of O phase in oil quenching and β (disordered) + O phase in water quenching. The metastable β phase decomposes into O + ω, O, or α2 + β0/B2 phase when the as-quenched alloy is aged at various temperatures. By comparing the selection area diffraction patterns, it has been found that the ordered ω phase in the alloy studied in this article is distinct in structure to the ω type (P3m1) and B82 phase which are formed in the parent matrix of the ordered β(B2,D03) phases. It has also been shown by X-ray diffraction (XRD) analyses that the lattice parameters of the as-aged O phase do not remain constant in the alloy at various temperatures