Metal Injection Moulding: A Near Net Shape Fabrication Method for the Manufacture of Turbine Engine Component

摘要

Metal Injection Moulding (MIM) is an attractive technology for the net shape fabrication of small complex shape parts made of exotic materials such as stainless steels, nickel alloys, titanium alloys and ceramics. A novel process based on Low Pressure Injection Moulding (LPIM), has been developed in order to render the process more economically feasible for typically smaller batch sizes found in aeronautic applications. In this work, results on the processing and characterization of Inconel 625 LPIM material are presented. In depth microstructural characterization was performed on the starting powder and on thermally debound samples in order to properly understand the debinding process in relation with phases present in the microstructure of debound and sintered parts. Results indicate that a Nb and Mo rich phase found in the starting powder led to the formation of second phase particles such as M23C6, M6C and MC carbides as well as Laves phase in the debound and sintered samples. The sintering process indicated that the dissolution of second phase particles in the microstructure can be achieved and needs to be optimized with secondary heat treatment such as solution annealing.