Effect of Minor Additions of Boron on Microstructure and Mechanical Properties of As-Cast Near α Titanium Alloy

Abstract

This work investigates the effect of boron addition on the microstructure and mechanical properties of a near alpha Ti alloy, Timetal 685 in as-cast plus heat-treated condition. While significant refinement of the prior β grain size is seen with small additions of boron, the thickness of α lath (in transformed β structure) increases with increasing boron. At room temperature (RT), tensile yield strength increases marginally, but the ductility drops significantly possibly because of the cracking of TiB phase. At elevated temperature, significant strengthening is observed in the boron containing alloys especially at higher plastic strains. Additionally, the creep resistance shows significant enhancement with boron addition.