Processing-microstructure-yield strength correlation in a near β Ti alloy, Ti-5Al-5Mo-5V-3Cr

A combined set of thermo-mechanical steps recommended for high strength β Ti alloy are homogenization, deformation, recrystallization, annealing and ageing steps in sequence. Recrystallization carried out above or below β transus temperature generates either β annealed (lath type morphology of α) or bimodal (lath+globular morphology of α) microstructure. Through variations in heat treatment parameters at these processing steps, wide ranges of length scales of features have been generated in both types of microstructures in a near β Ti alloy, Ti-5Al-5Mo-5V-3Cr (Ti-5553). 0.2% Yield strength (YS) has been correlated to various microstructural features and associated heat treatment parameters. Relative importance of microstructural features in influencing YS has been identified. Process parameters at different steps have been identified and recommended for attaining different levels of YS for this near β Ti alloy.