The Effect of Aging Heat Treatments on Room and High-Temperature Wear Performance of the Inconel 718™ Manufactured by Laser Powder Bed Fusion

This paper presents the results of a detailed experimental investigation into the wear properties of laser powder bed fusion samples of Inconel 718 after various aging conditions. There is a gap in the literature on the high-temperature wear properties of Inconel 718. The aging process determines the service life and working conditions of the alloy. This study aims to reveal the effects of various aging heat treatments on the room and high-temperature wear properties of Inconel 718. The aging conditions were selected as non-aged, solution aged (SA), conventionally aged (CA), overaged (OA) and furnace-controlled aged (FCA). Cylindrical samples were machined for 500 m, using a Si₃N₄ ball at room temperature and 400 °C. The surfaces of the samples were smoothed by turning. FCA was performed in a controlled atmosphere furnace. The heating and cooling rates of FCA were 10 min/°C. Ar was selected as the shielding gas. The rapid cooling stages of SA, CA and OA were performed by quenching in water. FCA refined the microstructure and enhanced the wear resistance. SA resulted in a rigid microstructure, abrasive wear was dominant. EA led to an increase in the Laves phase ratio, which was identified by X-ray diffraction analyses. Optical microscope and scanning electron microscope (SEM) images of the microstructures and worn surfaces were correlated with the microhardness scores to accurately define the wear properties. The precipitations were identified by energy-dispersive X-ray spectrum application that is combined to SEM. The experimental evidence from this work clarified the predominant wear mechanisms due to microstructure and phase evolution. This work provides remarkable information on determining the appropriate aging condition for various applications of Inconel 718 alloy.