Research on the microstructure and mechanical properties of doubled annealed laser melting deposition TC11 titanium alloy

•TC11 titanium alloy was prepared by laser melting deposition and subjected to double annealing heat treatment, so as to study the effects of different annealing temperatures and time on the microstructure and mechanical properties.•Affected by two competitive mechanisms of solidification nucleation, TC11 alloy microstructure exhibits columnar/ equiaxial alternate growth along the deposition direction.•As the annealing temperature increases in the dual-phase zone, the aspect ratio of the intragranular α phase decreases, and the grain boundary α phase appears discontinuous, spheroidized, and partial disappeared.. With the extension of the annealing time, the size of αs phase in the structure gradually increases and the intragranular α phase is coarsened significantly.•The microhardness of TC11 titanium alloy increases firstly and then decreases with the increase of annealing temperature. Double annealing can significantly improve the deposited mechanical properties.