1. State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, Xi’an 710049, China
2. National Key Lab of Aerospace Power System and Plasma Technology, Air Force Engineering University,Xi’an 710038, China
Additive manufacturing (3D printing) is a promising route to repair damaged Ni0based superalloy single crystal blades. This technology is featured by steep temperature gradient and high cooling rate. The characteristics favor the directional growth of dendrites and realise microstructure refinement. However, additive manufacturing process also produce high residual stress and high microstructural defect density, which will trigger disastrous recrystallization and cracking in the subsequent heat treatment and/or high temperature service process. Therefore, customized heat treatment is demanded for the 3Dprinting repaired Ni0based superalloy single crystals. The standard heat treatment of superalloy generally consists of the steps of super0solvus solution and aging. Considering the unique microstructure of as0printed single crystal superalloys, the strategies of rafting0enabled recovery and sub0solvus solutionizing are demonstrated in this work, which effectively prevent recrystallization and stray grain growth, reduce dislocation density, release stress, and optimize γ′ morphology and volume fraction. Our study paves the way for the 3D0printing repair of damaged Ni0based superalloy single crystal turbine blades.