Mitigation of Cracks in High‐Performance Nickel‐Based Superalloys in Powder Bed Fusion Laser Beam of Metals Using a Metal Matrix Composite Approach

The efficiency of gas turbines plays an important role for a sustainable energy transition resulting in high requirements for turbine blade materials. Nickel‐based superalloys, such as CM247LC, are often used for this application. Using additive manufacturing (AM), the major subtractive processing steps after conventional casting of turbine blades can be avoided and complex lightweight structures achieved. However, the nickel‐based superalloys withstanding the highest temperatures are prone to cracking during the AM process. This study presents a method to mitigate the cracking tendency of the non‐processable nickel‐based superalloy CM247LC in powder bed fusion laser beam of metals (PBF–LB/M) by adding reinforcing TiC particles resulting in a metal matrix composite (MMC). The focus of the investigation is put on the influence of the incorporated particles on the selection of PBF–LB/M process parameters and the evolution of the microstructure. The results show a reduction in crack length and density in the new MMC by grain refinement and a homogeneous distribution of local strains. Heat‐treatment and hardness testing reveal a transformation of the TiC to (Hf,Ta,W)C and γ′ as well as excessive grain coarsening.