X‐ray diffraction study on phase transformation of Ti‐22Al‐23Nb‐1Mo‐1Zr alloy during high‐pressure torsion

Titanium aluminum niobium‐based alloy is one of the most promising high‐temperature structural materials in aerospace field, whose phase transformation mechanism has been extensively studied. In this paper, the lamellar O‐phase of Ti‐22Al‐23Nb‐1Mo‐1Zr alloy is found being transformed to B2‐phase at ambient temperature by high‐pressure torsion. Further x‐ray diffraction investigation shows that such transformation is related to the accumulation of lattice strain in the O‐phase. When the lattice strain in the O‐phase accumulates to an upper limit, the O‐phase will be transformed into the B2‐phase by shear transformation. Finally, the mechanism of phase transformation is discussed.