Process-structure relationship and microstructure evolution of Ti–22Al–25Nb alloy under heat treatment

Abstract

This paper investigates the Ti-22Al-25Nb alloy by first determining the phase transition points for each phase region using DSC and metallographic methods. It then examines the microstructure evolution under different heat treatment processes in the O+B2 and α₂+O+B2 phase regions. The study analyzes the effects of solid solution temperature, solid solution time, aging temperature, and aging time on the microstructure. It establishes models relating solid solution temperature to the average thickness of primary slat O, solid solution temperature to B2 grain size, and aging temperature to the average thickness of secondary slat O. Additionally, an error analysis of these models is conducted, providing valuable guidance for understanding the process-structure relationships in Ti-22Al-25Nb alloy.