Fabrication And Analysis Of Porous Superalloys For Turbine Components Using Laser Additive Manufacturing

This paper discusses the fabrication and manufacturing process of a simulated leading edge portion of a turbine blade with a porous superalloy structure constructed using Laser Additive Manufacturing (LAM) techniques. The LAM method was assessed based on its ability to successfully fabricate complex, porous structures within traditional turbine components. To simulate the manufacturing process, the leading edge was designed, fabricated, heat-treated and closely examined for manufacturing accuracy. Manufactured out of Inconel, the leading edge is a single piece which is capable of both internal and external cooling through the use of shower head cooling as well as with an internal cavity undergoing jet impingement cooling. The internal structure was designed as a lattice of intersecting holes in order to mimic that of a porous material. External hole geometry was measured to determine the accuracy and tolerances of the manufacturing process in order to analyze the hole uniformity over the leading edge portion of the blade. Flow testing was performed in order to characterize the effective flow area and uniformity at the exit of porous structures at multiple pressure ratios. The velocity field at the exit was measured and compared with the physical geometry in order to pinpoint manufacturing defects. The analysis outline yields quantitative data on the LAM process, providing insight as to whether or not it is a viable option for current turbine blade production