Office of Technology Transfer – University of Michigan

Direct metal deposition of single crystal superalloys and metals

Technology #6352

Gas and steam turbine blades made from single crystal structures offer significantly improved creep strength, thermal fatigue resistance, and corrosion resistance compared to equiaxed crystal structures. However, current methods of single crystal airfoil manufacturing require custom manufacturing of expensive, heat-resistant molds in order to cast the blades. In high performance applications where components are finely customized, these methods can be extremely costly and slow. A new single crystal manufacturing method using direct metal deposition (DMD) can overcome these challenges, bringing highly customized rapid production to turbine airfoil production.

Melt pool temperature control enables direct digital manufacturing

Adapting techniques from rapid 3D prototyping, the new process uses temperature feedback control on the melt pool during DMD fabrication. This control finely tunes the temperature gradient to force single crystal growth upon a seeding substrate, while moveable stage allows customized designs to be produced directly from digital design tools. A small prototype system has already demonstrated fabrication of a 22mm single crystal, and larger systems are in development.

Applications

  • Customized production of turbine blades
  • Single crystal design manufacturing

Advantages

  • Bypasses the need for expensive and time-consuming mold manufacturing before casting
  • Allows for direct prototyping and production from digital design tools