不同热处理对激光定向能量沉积制造 TC4 钛合金组织和拉伸性能的影响

Laser directed energy deposition (DED) is a manufacturing technology for producing high performance fully dense near-net metallic components, which is melting metal powders point by point and stacking them layer by layer. Since the microstructure of DEDed TC4 titanium alloy is different from that made by traditional forging, selecting appropriate heat treatment process can improve its mechanical properties significantly. The effects of three different heat treatment on microstructure morphologies and tensile properties of DEDed TC4 alloy were investigated. The results show that after 600 ℃ and 800 ℃ annealing treatment, the α lamellae coarsens to different degrees, and the volume fraction of α phase increases slightly. The double annealing heat treatment at 975 ℃ results in the appearance of equiaxed α phase, improving room-temperature plasticity with about 26.1% higher in average transverse reduction of area than that after 800 ℃ annealing treatment. After double annealing heat treatment at 975 ℃, TC4 alloy has the highest transverse average elongation at high temperature tensile test at 400°C, showing excellent high temperature strength-plastic balance.