Mechanical Properties and Corrosion Resistance of MIM Ni-Base Superalloys

Johnson, J. L., Tan, L. K., Suri, P., & German, R. (2004). Mechanical Properties and Corrosion Resistance of MIM Ni-Base Superalloys. Advances in Powder Metallurgy and Particulate Materials - 2004, Part 4. Princeton, NJ: Metal Powder Industries Federation. 89-101.

Abstract

Superalloys based on nickel exhibit a combination of strength and resistance to surface degradation that make them useful for many applications. Metal injection molding (MIM) of HX, 718, and 625 is evaluated. Sintering conditions for these alloys are optimized to achieve maximum density and their microstructures are characterized. 718 and 625 achieve high sintered densities via supersolidus liquid phase sintering, but pore-grain boundary break-away occurs for HX before liquid forms so lower sintered densities are achieved. The mechanical properties of MIM 718 and 625 are compared to cast, wrought, and previously reported MIM properties. The corrosion resistance of these materials is tested in various media and compared to 316L stainless steel and commercially pure Ni. While these two materials perform well under oxidizing and reducing conditions respectively, the superalloys, especially 625, perform well in both types of corrosive environments.