Investigation on compaction pressure and sintering temperature suitable for Nimonic 90 superalloy

Abstract

Fabrication of high strength, high temperature and corrosion resistant materials provide much assistance in aerospace, automotive, chemical and oil industries, as they have to withstand severe operating conditions. Traditionally, superalloys are widely used under these conditions that are prepared by casting method. Nowadays, powder metallurgy technique is gaining importance for preparing superalloys because of its capability of making homogeneous microstructure with near-net-shape. In this significant context, the processing of Nimonic 90 superalloy sample using conventional powder metallurgy route is discussed. Desired amount of metallic powders by weight percent are blended, uni-axially pressed and sintered in tubular vacuum furnace at different sintering temperatures. The influence of compaction pressure and sintering temperature on density, hardness, surface roughness and electrical resistivity is determined. Surface porosity and the effect of sintering temperature on the microstructural features are analyzed noticeably. It is found that the compaction pressure of 700 MPa and the sintering temperature of 1365℃ are the most desirable process parameters, essentially required for synthesizing the Nimonic 90 superalloy. Sample prepared under these conditions has achieved the desired density and hardness, as that of the standard Nimonic 90 alloy. Thus, the study paves the way for future researchers to appropriately identify the conditions suitable for preparing the superalloys as per the application needed.