Effect of boron microalloying on microstructure, tensile properties and creep behavior of Ti–22Al–20Nb–2W alloy

The effect of 0.2 at.% boron addition on the microstructure, tensile properties, and creep behavior of Ti–22Al–20Nb–2W were investigated. A TiB phase was observed in the B-doped alloy, which shows that the solubility of boron in this alloy is very low. The addition of 0.2 at.% boron was very effective in reducing the prior β-grain size of the Ti–22Al–20Nb–2W alloy, which is thought to be due to a strong boron segregation at the grain boundaries. The decrease in grain size due to the addition of boron is effective in improving the alloyʹs room temperature ductility. The addition of a small amount of boron was beneficial in lowering the steady-state creep rate at 650°C/310 MPa, but did not improve the creep behavior at 750°C/310 MPa.