Development of a model for prediction of material properties of laser cladded inconel 718 as related to porosity in the bulk material Available to Purchase

High value jet engine components such as compressor blades or BLade Integrated DiSKS (BLISKS) are manufactured by time and cost-prohibitive conventional techniques, such as five-axis milling, linear friction welding and electro chemical machining. This project within the Fraunhofer Cluster of Innovation “TurPro” qualifies the Laser metal deposition process (LMD) as a new “green manufacturing” method for nickel and titanium alloy-based BLISKs. Thus, a significant increase of the deposition rate (factor 10 or higher) is of interest. Aiming for a process certification of additive manufacturing of BLISK blades, using conventionally manufactured disks as a substrate, quality assurance and predictable material properties remain a major concern. In this paper, the distribution of pore sizes of laser deposited Inconel 718 (IN 718) is investigated, using laser powers of up to 5.5 kW and deposition rates of up to 7000 mm³/min. Using quantitative image analysis, defining sub-sets and applying extreme value and logarithmic Gaussian distribution, the pore-size-distribution in the bulk material can be described with merely 4 statistical parameters. Based on these parameters, the ultimate tensile strength (UTS) of a cladded sample can be estimated with an accuracy of approx. 250-300 MPa.