The Laser Power Effect on the Microstructure and Properties of TC21 Titanium Alloy Formed by Laser Selective Melting

The effects of laser power on the roughness, relative density, microstructure, hardness, and electrochemical corrosion properties of TC21 titanium alloy were studied by SLM, and the optimum process parameters were determined. The results show that the microstructure of the sample is mainly composed of lamellar α′ grains, and the roughness during sample forming shows a decreasing trend with the increase of laser power. When the laser power of the sample is 170 W, the relative density reaches the highest value of 98.65%, the roughness reaches the lowest value of 9.16 μm, and the hardness reaches 543 HV. The current density and corrosion potential are \(i{\text{corr}}\)  = 4.470 × 10–2 A·cm−2 and \(E{\text{corr}}\)  = −0.207 V, respectively. In this case, the oxide film of the sample is the most stable and has the strongest corrosion resistance. The optimal parameters obtained in this experiment are as follows: laser power is 170 W, scanning speed is 400 mm·s−1, scanning spacing is 0.07 mm, and powder layer thickness is 0.02 mm.