Abstract:The microstructure and mechanical properties of a novel Nickel-based powder superalloy FGH4113A under two heat treatment conditions were studied by means of scanning electron microscope (SEM), optical microscope (OM), tensile, creep and fatigue testing, providing the basis for dual microstructure heat treatment (DMHT). The results show that the supsolvus and subsolvus microstructure and mechanical properties have obvious dual-mode. At room temperature, the yield strength of subsolvus sample is 10.6% higher than that of supsolvus samples, and at 800 ℃, the yield strength of supsolvus samples is 11.7% higher correspondingly; The tensile strength of FGH4113A is better than that of ME3 and equivalent to that of LSHR. The creep deformation of FGH4113A alloy at 750°C/450MPa is dominated by the dislocation slip mechanism, and the dispersed small-sized borides conducive to improve the creep performance; FGH4113A has excellent creep properties, which is better than ME3 and equivalent to LSHR; The coarse-grain structure in the supsolvus sample has a longer slip band in crack propagation, resulting in lower cumulative damage under cyclic loading, and the crack growth resistance is better than that of subsolvus sample; The crack propagation fracture of the supersolvus sample is characterized by transgranular fracture. The existence of primary γˊ on the fine grain boundary reduces the crack growth resistance, and the fracture is rough, showing mixed fracture characteristics of intergranular and transgranular.