From 3Ders.org:
World's hardest Christmas trees
With 3D printing processes, shapes can be produced that would be impossible using any other production process. Experienced material researcher Olaf Rehme of Siemens Corporate Technology (CT) has used a 3D printer to create Christmas trees from gas turbine steel. The special steel that Rehme uses for printing the Christmas trees is a nickel alloy.
During the process, commonly known as direct metal laser sintering, the laser beam moves across the bed of metal powder, releasing high energy in the form of heat and melting the metal, and generates an initial layer of the three-dimensional object. Parts are built up additively layer by layer. At the end of the process, a large amount of powder is left over that can be reused for the next printing cycle. This process allows for highly complex geometries to be created directly from the 3D CAD data, fully automatically, in hours and without any tooling.
If you look closely, you'll see the printed tree's fine structure.
Siemens has been using 3D printing processes to speed up gas turbine repair. For certain types of turbines, defective burner parts are simply reprinted on a 3D printer, reducing repair times by as much as 90 percent. Researchers at Siemens CT are now working on processing techniques that would be able to printing objects with extremely high ductility. To generate electricity, turbines have to turn and turn fast. It means that materials of turbine blades need to have high ductability against the massive centrifugal forces. 3D printing with metals can't yet meet these demands. For the little steel-hard trees, however, the technology is sufficient....MORE
