The Effect of Temperature on the Microstructure of a Metastable β Ti Alloy

A metastable β titanium alloy, BTi-6554 (Ti-6Cr-5Mo-5V-4Al) has been developed for structural applications in aircraft because of its high strength, high toughness, and good fatigue properties. This paper reports on the effect of heat treatment on microstructure and microhardness of the alloy. It has been shown that in the as hot rolled condition, the alloy consists of a single β phase. Heat treatment between 450-750°C results in the precipitation of α laths, while exposure to temperatures between 700-800°C results in the gradual transformation of the α phase back to β phase with larger grain sizes resulting from higher heat treatment temperatures