Effect of Solution Temperature on Microstructure and Mechanical Properties of Selected Laser Melting Formed TB6

TB6 titanium alloy specimens were fabricated by means of selective laser melting technology, and the solution treatment at different temperatures and aging at 540 ℃ ×8 h was carried out for the specimens. The influence of the solid solution temperature on the microstructure and mechanical properties of the alloy was investigated. The results indicate that after solid solution and aging, the microstructure of the alloy is refined from columnar β grains to equiaxed grains, and a large number of granular or lamellar α phases and grain boundary α_GBphases are generated. With the increase of solid solution temperature, the size of β grains grows rapidly, increasing from an average grain size of 53 μm at 760 ℃ to 693 μm at 840 ℃,and the volume fraction of lamellar α_L gradually decreases, the continuity degree of α_GB phase is reduced. The tensile test results reveal that with the increase of solid solution temperature, the tensile strength of the material decreases, it decreases from 1227 MPa at 760 ℃ to 1186 MPa at 840 ℃, and the elongation after fracture first rises and then drops, which reaches a peak of 10.3% after 780 ℃ solid solution and aging. It is discovered that the morphology of the α phase and the change of βgrain size affect the strength and plasticity of the alloy. The increase of grain size and the decrease of α phase seriously affect the mechanical properties of the material.