Structure and vibration characteristics of Ti-Al-Mo-V alloy

Abstract

Ti-5Al-2.5Mo-1.4V rolled plates were subjected to solid-solution heat treatment at 870 or 930^∘C for 1 h and aged for 1–8 h at 460^∘C to investigate the relationship between the microstructure and the vibration characteristics of the alloy. According to the experimental results, the S870 solid solution matrix contains α + α′ + β structures and the S930 solid solution specimen possesses α +α′ structures (β transus is ∼ 900^∘C). Increasing the α′ phase content improves strength and hardness but reduces ductility. It also promotes internal friction and thus increases damping. During the 460^∘C aging process, the α′ phase in the β region of S870/Ah grows and transforms into a finer needle structure and the primary α phase (bounded by prior β grain boundary) of S930/Ah grows within the α′ matrix. Both S830/Ah and S930/Ah reveal similar tendencies in mechanical properties with increased aging time. When the aging time exceeds 1 h, S870/Ah, having a large quantity of β phase, has a better vibration damping ratio than S930/Ah (containing a great quantity of primary α phase).