3D printing and coating of heat-resistant objects, such as a turbine blisks or blades
This depends primarily on economics and on desired lifetime.  Rather obviously you need a material whose strengths and melting points exceed the operational specs.  Determining the various break strengths (shear, bending, etc) is an engineering problem, not a manufacturing problem per se.
Next, consider the production time and cost of 3D-printing vs. some typical assembly line process.  Nearly always the 3D approach loses for large quantity builds.
Designing and operating devices like this can be extremely dangerous. Very tight tolerances are required.  This site describes the difficulties, starting with material choice, moving on to tolerances, and so on.  I don't think you want to go at this in your basement.