Effects of microstructure on the room-temperature strength and ductility of the alloy Ti-25Al-10Nb-3V-1Mo

The role of the microstructure on the room-temperature tensile properties of the alloy Ti-25Al-10Nb-3V-1Mo (at.%) was investigated. A wide spectrum of microstructures was obtained by varying the cooling rate after a solutionizing treatment in the β phase field. The strength was found to increase monotonically with increasing cooling rate. It is proposed that strength is controlled by (α2 + βR) boundary strengthening in β-solutionized microstructures. The ductility was observed to go through a maximum at a cooling rate of 1.5 C/s. Different deformation and failure mechanisms were identified, depending on the cooling rate regime, and correlated to the ductility trends. The βR nature, α2 lath size, α2 lath arrangement and prior-β grain boundaries appeared to be the principal features governing the deformation and failure mechanisms