In-situ measurement of the β to α phase transformation kinetics in a Ti-5553 alloy using laser ultrasonics

Abstract

Ti-5553 alloy (Ti-5Al-5Mo-5V-3Cr wt.%) is one of the newest high strength metastable β-titanium alloys to be used in large section components of aircraft structures. Like other Ti-alloys, Ti-5553 can be strengthened by precipitation of the α-phase during aging heat treatments. In the present study, we explored the potential of laser ultrasonics for metallurgy (LUMet) as an in-situ tool to measure the α precipitation kinetics during high temperature isothermal aging in a Ti-5553 alloy. The observed change in longitudinal ultrasound velocity was seen to be linearly correlated with the α-phase fraction measured via post-mortem electron microscopy. The results are promising for a wider use of LUMet to design optimized heat treatment schedules for commercial Tialloys. Laser ultrasonics offers the potential for real-time monitoring of microstructure evolution in industrial production lines.