The effect of heat treatment on microstructure evolution and tensile properties of selective laser melted Ti6Al4V alloy

The phase transition, microstructure, detailed structures and tensile properties of selective laser melted Ti6Al4V alloy were been examined and analyzed. The results reveal that the as-fabricated Ti6Al4V samples consist of lamellar α' and acicular α'. Much twins in the lamellar α' and small α2 precipitation in the acicular α' were found. The effects of different heat treatment methods on the as-fabricated samples were also investigated. As a result of the microstructure evolution, samples heat-treated at 800 °C and 850 °C for 4 hours and cooled in air contain the most β and the finest lamellar α, exhibiting good comprehensive properties. •The as-fabricated Ti6Al4V samples consist of lamellar α' and acicular α'.•Twins and small α2 precipitation were found in the as-fabricated α'.•α' transforms to α+β rapidly when the temperature higher than 750 °C.•Lamellar α and acicular α' dominate after the quenching-aging treatment.•The 800 °C/850 °C annealing-treated samples exhibit good comprehensive properties.