Tensile properties and deformation characteristics of nickel-iron-based superalloys for steam turbine rotors
摘要
This study investigates the microstructural evolution and tensile properties of a new nickel-iron-based high-temperature alloy, HT700R, after solution treatment and ageing treatment. The results show that the yield strength of the aged alloy is higher, while the plasticity and toughness of the solid solution-treated alloy are better. Notably, solid solution alloy yield strength is lower at tensile temperatures lower than 600 °C. Still, when the temperature reaches 650 °C, solid solution alloy yield strength will increase rapidly due to the precipitation of γ′ phase. In addition, the tensile deformation mechanism at the critical temperature inflexion point (600 °C) of the HT700R alloy was investigated by tensile tests, SEM and EBSD, and TEM techniques, and the tensile properties, dislocation substructure and grain orientation evolution were analyzed.