Effect of annealing temperatures on microstructure and mechanical properties of laser melting deposited TA15 titanium alloy

TA15 bars and plates were fabricated by laser melting deposition manufacturing. The effect of annealing temperature on microstructure and mechanical properties of laser melting deposited TA15 alloy has been studied. The experimental results show β grains of the alloy has excellent high temperature stability. The microstructure of the as-deposited alloy is the typical lamellar transformed β. A special bi-modal structure with regular stripe-shaped primary α is produced by annealing in the upper α+β field, and volume fraction of the primary α decreases with the increasing annealing temperature. The microstructure of β annealing is fine lamellar transformed β. The ultimate tensile strength of the plates declines because of the coarsening of primary α in α+β field. The ultimate tensile strength and elongation are improved after annealing at 940°C. The ultimate tensile strength is unchanged but the elongation is a bit worse after β annealing.