Additive manufacturing (AM) is a new manufacturing method that allows engineers to design complex parts that are difficult to manufacture by conventional methods. Nickel based superalloy Inconel 718 is one of the most used alloys in metal AM because of its wide range of applications seen in aerospace and energy industries due to its excellent resistance to creep and oxidation.
Recently, some of the critical components in aerospace engines such as fuel nozzles and other structural components manufactured through conventional techniques are replaced with the AM processed components. Mechanical damage due to fretting wear seen on these high value components are very severe as they are subjected to simultaneous cyclic load and slip at the contact at elevated temperatures.
Though the Laser-based powder bed fusion (L-PBF) technology is an effective way to manufacture Inconel 718 components, the mechanical, tribological and metallurgical performance are not reported comprehensively. As Inconel 718 is a precipitation strengthened alloy that is generally heat-treated before being put into use, it is also very important to determine the interrelationship in between heat treatment conditions and tribological characteristics of this material processed by L-PBF technique.
In this present study, various heat treatment cycles will be applied to AM processed Inconel 718 specimens. Thermal treatments such as homogenizing and solutionizing are planned at 1080°C and 980°C respectively with two holding times (1 hr. and 0.5 hr.) each and followed by double ageing treatments. As a result of heat treatment, microstructure, tensile strength and hardness will be examined and compared with conventional wrought specimens. Furthermore, the effect of heat treatment on fretting wear behavior, which is a very crucial required property for Inconel 718 will be extensively studied under various testing temperature and stress levels.
Keywords: Fretting wear; additive manufacturing; Inconel 718; heat treatment.