Custom-designed heat treatment simultaneously resolves multiple challenges facing 3D-printed single-crystal superalloys

Single-crystal Ni-based superalloys are currently the material of choice for turbine blade applications, especially with emerging additive manufacturing (AM) that facilitates manufacture/repair these single crystals. This promising AM route, however, comes a dilemma: in fusion and heat affected zones after e-beam or laser induced melting, one needs solutionizing annealing to relieve residual stresses homogenize chemical/microstructure. The super-solvus temperature is usually adopted from protocol cast superalloys, which almost always causes recrystallization stray grain growth, resulting polycrystalline microstructure degrading high-temperature mechanical performance. Here we demonstrate custom-designed post-printing treatment replace conventional one. recovery relatively low diminish driving force movement boundaries, without suffocating chemical/microstructural homogenization thanks narrow dendrite width short element segregation distance. optimal duration proposed achieve atomic-diffusion mediated chemical while limiting γ′-particle coarsening interdendritic regions. Our strategy makes it practically feasible resolve several bottleneck problems processing/treatment, removing seemingly formidable obstacle effective superalloy crystal products.