Turbine blades in modern aircraft are gamma-TiAl, which is a single crystal. These are not 3d printed and the process for making them is similar but more advanced than making silicon wafers.
This is a decent documentary on Rolls Royce that discusses the single crystal blade. I think each one has 18 tons of centrifugal force, and uses a few micron layer of air to cool it, so running an engine too slow will melt them. Fascinating stuff.
