The effect of boron addition on the high-temperature properties and microstructure evolution of high Nb containing TiAl alloys

The effect of boron addition on the microstructure evolution and high-temperature properties of Ti-43Al-6Nb-1Mo-1Cr alloys has been studied in this paper. With the boron content increasing from 0 at% to 1.0 at%, the ultimate tensile strength(UTS) at high temperature increase dramatically while the alloys with 1.0at%B exhibit UTS as 656.12 ± 20.54 MPa at 800 °C, 642.43 ± 14.44 MPa at 850 °C and 508.44 ± 16.12 MPa at 900 °C, respectively. Meanwhile, boron addition could stabilize the high-temperature UTS of the alloys in 500-700 MPa with the temperature incresasing. Three types of strengthening mechanism in high-temperature strength caused by boron addition are also discussed and concluded.