Method of Suppressing Solidification Cracking by Laser Surface Melting and Epitaxial Growth Behavior for Directionally Solidified 247LC Superalloy

In this study, the relationship between solidification cracking and epitaxial growth behavior with high-speed laser surface melting of a directionally solidified 247LC superalloys was fundamentally metallurgically investigated, to develop successful welding procedure for next generation gas turbine blades. Under typical conditions (scan speed: 50 mm/s, heat input: 40 J/mm), severe phenomena occurs. The key metallurgical factors have been identified as segregation-assisted pipeline diffusion at grain boundary, in randomly formed polycrystalline zone microstructure. addition, under extremely low input beam scan 1000 2 an effective can be obtained within single relatively high-energy density (65 J/mm2) using characteristics single-mode fiber lasers. Results reveal that successfully shows 99.9% achievement ratio. Because superior ratio zone, rapid phenomena, formation boundary suppressed. Finally, crack-free thus achieved.