Temperature-dependence tensile behavior and deformation mechanism of GH4099 Ni-based superalloy manufactured by laser powder bed fusion (LPBF)

GH4099 nickel-based superalloy exhibits excellent LPBF compatibility and high-temperature strength-ductility balance, yet its mechanisms for strength and ductility loss at high-temperature remains unclear, hindering its applications. This work investigates the microstructural evolution and tensile behavior of LPBF-fabricated GH4099 at 25 °C, 600 °C, and 900 °C. Results show that high-temperature mechanical degradation is linked to the deformation mechanism transition: dislocation slip dominates at 25 °C and 600 °C, with dislocations shearing of γ’ phases strengthening the alloy. At 900 °C, annealing twinning prevails, which fraction enhanced by increased intragranular carbides, strengthen through dislocation interactions with their low energy boundaries, mitigating properties loss. The LPBFed GH4099 prepared in this work achieves ultimate tensile strength of 1222, 1091, 444 MPa and yield strength of 850, 767443 MPa, respectively at 25, 600 and 900 °C, with elongation of 24.4, 17.4 and 13.8 %. The superior mechanical properties, particularly at 900 °C, outperforming other GH4099 alloys.

Duke Scholars

Author Zhaohui Wang Pathology