Consolidation of Nickel Base Superalloys Powder by Low Pressure Plasma Deposition

The low pressure plasma deposition process has been evaluated as an improved plasma deposition and powder consolidation process. The microstructures and properties presented for these selected nickel-base superalloys demonstrate that this new development in plasma deposition can produce consolidated superalloy P/M structures equivalent to other consolidation processes. The plasma deposition parameters, alloy deposited and powder size can all affect the consolidation mechanics by affecting the amount of liquid present during particle impaction. In addition, it has been shown that the alloy can significantly affect both as-deposited and final consolidated (heat treated) microstructure and properties. Alloys which are less stabilized by interstitial elements (i.e. carbon, zirconium, and boron) seem to show more grain growth both during deposition and after final heat treatment. Alloys similar to U-700LC can be expected to show better ductilities and rupture strengths due to the increased grain size.