Laser Additive Manufacturing of Nickel Superalloys for Aerospace Applications

Laser additive manufacturing (LAM), the most commonly used metal additive manufacturing process, uses high power lasers to melt feedstock materials for fabricating high-performance engineering components involving complex geometries and multi-materials with reduced lead time. The LAM process provides freedom for shape design, material design, post-processing and logistics and, therefore, the technology is being increasingly adopted by various industrial sectors such as the automotive, aerospace and medical. Among the various sectors, the applications of LAM in the aerospace sector are increasing at a brisk pace and the application domain ranges from cladding to repairing to the fabrication of near-net-shaped engineering components. The increasing popularity of LAM in the aerospace sector is due to its ability to fabricate components with low buy-to-fly ratio, provide unlimited customization and process difficult to machine materials. One of the commonly used class of materials in the aerospace sector are nickel superalloys due to their high performance at elevated temperatures, including high-temperature strength, oxidation resistance and corrosion resistance. Globally, researchers are working on the LAM processing, characterization and qualification of various nickel superalloys for aerospace applications. This chapter introduces the LAM process with a detailed description of the LAM system, processes and process parameters. The chapter will also describe the LAM of the most commonly used nickel superalloys, explaining the effect of LAM process parameters and process conditions on the quality of the build, microstructure of the LAM built samples and their mechanical properties. In addition, the microstructure and mechanical properties of LAM-built nickel superalloys will be compared with post-processed components and conventional counterparts. Further, various applications of LAM in the aerospace sector will be explained using case studies.