Microstructure and mechanical properties of injection moulded Nimonic-90 superalloy parts

Abstract

This study aims to determine optimum sintering and heat treatment parameters of powder injection moulded Nimonic-90 powder parts. Determination of optimum heat treatment conditions for sintered parts aimed to achieve maximum densities, and the microstructure and mechanical properties of the produced parts were characterised in sintered and heat treated conditions. Injection moulding feedstock was prepared by mixing Nimonic-90 powder with a multicomponent binder system. After moulding, the samples were subjected to a debinding process that consists of solvent and thermal steps. To determine the sintering temperatures, the debinded samples were subjected to differential scanning calorimetry analysis, and then they were sintered at various temperatures under high level vacuum. After sintering, density measurements and optical microscope examinations were performed. The highest density values were determined for the samples that were sintered at 1330uC for 3 h. Different aging treatments were performed on the samples that achieved the highest sintered density, and the microstructures and mechanical properties were then characterised. It was determined that heat treatments had a beneficial effect on the mechanical properties of the material. Though the mechanical properties of the injection moulded materials produced were lower than the wrought Nimonic-90 materials, they have superior mechanical properties compared with cast Nimonic-90 alloys.

Powder bed binder jet printed alloy 625: Densification, microstructure and mechanical properties

“…Thus, varying contributions to the hardness are dominant at different sintering conditions and are visible in the density measurements, OM and SEM/EDS observations. Similar results were reported by Ozgun et al for traditionally-manufactured Nibased superalloys [12,18,24,25].…”

“…It is reported that a relative density of 96% with an average particle size of 12.5 μm as a result of sintering performed for 2 h in 5% hydrogen and argon at 1235 °C [26]. A difference in the obtained results in this study is due to the larger particle size used, since the driving force of sintering is a decrease in surface energy [18,25]. Ozgun et al reported that powder injection molded alloy 625 powders with the average particle size of 11.1 μm sintered at 1300 °C for 3 h resulted in 98% density.…”

Enhancing Mechanical Properties of the Spark Plasma Sintered Inconel 718 Alloy by Controlling the Nano-Scale Precipitations

“…The lattice misfit is used to evaluate the strain state at the interfaces of phases, which greatly influences the high-temperature properties of superalloys. It is generally believed that in the high-temperature creep tests, a higher microstructure stability is expected when the misfit between phases is smaller [33,34]. Due to the expanding of γ lattice, the misfits between γ’’ and γ became larger with increasing solution temperatures.…”

The effect of aging treatment on the fracture toughness and impact strength of injection molded Ni-625 superalloy parts

“…Recently, PIM of superalloys has attracted great attention for a variety of gas turbine engine parts [3][4][5][6][7][8][9][10].…”