Effects of Si on Microstructures and High Temperature Properties of Beta Stabilized TiAl Alloy

Abstract

The effects of Si addition on microstructures, high temperature compressive properties and creep properties of the β-stabilized Ti-45Al-3Fe-2Mo alloy have been studied in this work. The results show that the Si addition decreases the volume fraction of β phase and precipitates particulate Ti₅Si₃ phase. At the same time, the Si addition improves the high temperature strength of the Ti-45Al-3Fe-2Mo alloy for about 200 MPa at 800°C and decreases the creep strain for about 35% at 800°C under an applied stress of 150 MPa. The decrease in volume fraction of β phase and precipitation of Ti₅Si₃ particles are believed to be the dominant mechanisms for the improvement of the high temperature properties of the Si-doped TiAl alloy.