Recent research progress in the mechanism and suppression of fusion welding-induced liquation cracking of nickel based superalloys

Nickel-based superalloys are extensively used in the crucial hot-section components of industrial gas turbines, aeronautics, and astronautics because of their excellent mechanical properties and corrosion resistance at high temperatures. Fusion welding serves as an effective means for joining and repairing these alloys; however, fusion welding-induced liquation cracking has been a challenging issue. This paper comprehensively reviewed recent liquation cracking, discussing the formation mechanisms, cracking criteria, and remedies. In recent investigations, regulating material composition, changing the preweld heat treatment of the base metal, optimizing the welding process parameters, and applying auxiliary control methods are effective strategies for mitigating cracks. To promote the application of nickel-based superalloys, further research on the combination impact of multiple elements on cracking prevention and specific quantitative criteria for liquation cracking is necessary.