Enhancing Internal Cooling Channel Design in Inconel 718 Turbine Blades via Laser Powder Bed Fusion: A Comprehensive Review of Surface Topography Enhancements

Inconel 718, a widely utilized Ni-based superalloy in the aerospace industry, is renowned for its exceptional mechanical properties, high-temperature corrosion resistance, and thermal stability, making it an ideal material for turbine blades operating under extreme conditions of up to 2200 °C and high-pressure. Traditional single crystal casting, the prevalent manufacturing method for turbine blades, poses inflexibility challenges. Laser Powder Bed Fusion Additive Manufacturing (LPBF-AM) emerges as a disruptive alternative, providing flexibility and intricate design possibilities. However, LPBF-fabricated turbine blades face challenges, notably low thermal stability due to the polycrystalline microstructure. To address this, implementing an internal cooling channel to the turbine blade geometry can overcome this challenge. The flow of cooling fluid inside the cooling channel absorbs the heat of turbine, and maintains the turbine at low-temperature. The performance of internal cooling channel can be improved by implementing controllable surface texture to provide the heat sink mechanism. Nowadays, the LPBF has opportunity to fabricate the complex geometry of turbine blade with surface-textured internal cooling channel. This review delves into the specific requirements for the next generation of turbine blades featuring surface-textured internal cooling channels. It covers considerations such as geometric design, LPBF parameters, metallurgical aspects of processing Inconel 718, and quality testing encompassing material properties and geometric accuracy. Additionally, the review outlines existing challenges and research prospects in LPBF of Inconel 718 for advancing turbine blade components. In conclusion, the review inspires further development in high-performance Inconel 718 turbine blades, emphasizing advancements in surface textures and internal cooling channels via LPBF.