Metal Additive Manufacturing Conference 2019

Laser Metal Deposition (LMD) as a repair technology has been established in recent times. A commonly used material for repairs of turbines are nickel-base alloys, such as Inconel 718 (IN718), which presents good mechanical properties at temperatures up to 650 °C and good corrosive resistance. Inclined or curves surfaces pose a challenge in repairing parts with LMD due to the dependence of height and width of deposited tracks on the local inclination angle. An extensive preparation on path planning is needed to ensure high densities and good properties of the deposited material. This paper is a systematic study of LMD of IN718 on inclined planes for a better understanding of changes in the geometry of deposited material tracks. In a first step, height and width of single tracks at various inclinations are evaluated by optical profilometry and metallographic cross sections. The deposition process is recorded with high speed videography and particle trajectories are evaluated. Then, heights of layers built with three different scanning strategies are analysed: a) horizontal single tracks starting from the top going down, b) horizontal single tracks starting from the bottom going up, c) single tracks going up and down. Furthermore, the influence of inclination on dilution of the base material and on defects such as pores and bonding defects is investigated. By studying the basis of LMD on inclined surfaces, this paper helps to improve and accelerate path planning for repairs by LMD on complex surfaces and to shorten preparation time for repairs of new geometries of parts to be repaired.