On Cracking and Microstructure of Ni-based Superalloy Inconel 738LC by Selective Laser Melting: The Influence of Processing Parameters

Additive Manufacturing (AM) of Ni-based superalloys can potentially further enhance the efficiency of gas turbine engines by enabling more efficient design geometries and reduction in the number of parts. Selective laser melting (SLM), as one of the AM techniques, is particularly attractive in this regard due to its relatively high dimensional resolution and better surface finish. However, common nickel alloys in the market for AM are in the lower-end of the high temperature performance spectrum, limiting the application in gas turbines. Most high-strength, gamma-prime strengthened Ni-based superalloys, such as Inconel 738LC, have been challenging to produce by SLM due to their high cracking susceptibility. In our research on Inconel 738LC by SLM, we observed substantial differences in cracking intensity from variations in different SLM parameters. Different SLM processing was also found to affect the microstructure and potentially the high temperature properties of the alloy.