Grain refinement and excellent mechanical properties of a Ti-based alloy via laser melting and subsequent low temperature annealing

Compared with arc melting, ultrahigh strength and good elongation of Ti-25Zr-10Al alloy via laser melting and subsequent low temperature annealing are investigated. The results show a strong dependency of the microstructure on the methods of melting and subsequent low temperature annealing process. Compared with orthorhombic α'' martensitic phase after arc melting, at the condition of relatively high cooling rate by laser melting, hexagonal close-packed α' martensitic phase with {101̅1} twinning is observed, and recrystallization with the average grain size of 0.3 µm occurs after subsequent low temperature annealing. In addition, ultrahigh strength of 1352 MPa and good elongation of 10.9% are obtained.