Crack Types, Mechanisms, and Suppression Methods during High-energy Beam Additive Manufacturing of Nickel-based Superalloys: A Review

Nickel-based superalloys have been widely used in aerospace fields, especially for engine hot-end parts, because of their excellent high-temperature resistance. However, they are difficult to machine and process because of their special properties. High-energy beam additive manufacturing (HEB-AM) of nickel-based superalloys has shown great application potential in aerospace and other fields. However, HEB-AM of nickel-based superalloys faces serious cracking problems because of the unique characteristics of superalloys, and this has become the most significant bottleneck restricting their application. In this review, the current research status related to the types, formation mechanisms, and suppression methods of cracks in nickel-based superalloys produced by HEB-AM is described. The initiation and propagation mechanisms of cracks and their multiple influencing factors are also analyzed and discussed. Then, several possible research directions to solve the cracking problems in nickel-based superalloys produced by HEB-AM are outlined. This review provides an in-depth and comprehensive understanding of the cracking problem in AM nickel-based superalloys. It also provides valuable references for AM crack-free nickel-based superalloy components.